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Led Zeppelin IV

The untitled fourth studio album by the English rock band Led Zeppelin, commonly known as Led Zeppelin IV, was released on 8 November 1971 by Atlantic Records. Produced by the band's guitarist, Jimmy Page, it was recorded between December 1970 and February 1971, mostly in the country house Headley Grange. The album contains the band's most well-known recording, the eight-minute-long "Stairway to Heaven".

The informal recording environment inspired the band, allowing them to try different arrangements of material and create songs in various styles. After the band's previous album Led Zeppelin III (1970) received lukewarm reviews from critics, they decided their fourth album would officially be untitled and represented instead by four symbols – one chosen by each band member –  without featuring the name or any other details on the cover. Unlike the prior two albums, the band was joined by guest musicians: the singer Sandy Denny on "The Battle of Evermore", and the pianist Ian Stewart on "Rock and Roll". As with prior albums, most of the material was written by the band, though there was one cover song, a hard rock re-interpretation of the Memphis Minnie blues song "When the Levee Breaks".

The album was a critical and commercial success and is Led Zeppelin's best-selling album, having shipped over 37 million copies worldwide. It is one of the best-selling albums in the United States and of all time, while critics have regularly placed it high on lists of the greatest albums of all time.

Writing and recording
Following the release of Led Zeppelin III in October 1970, the group took a break from live performances to concentrate on recording a follow-up. They turned down all touring offers, including a proposed New Year's Eve gig that would have been broadcast on television. They returned to Bron-Yr-Aur, a country house in Snowdonia, Wales, to write new material.

Recording sessions for the album began at Island Records' new studios on Basing Street in London on 5 December 1970, with the recording of "Black Dog". The group had considered Mick Jagger's home, Stargroves as a recording location, but decided it was too expensive. They subsequently moved the following month to Headley Grange, a country house in Hampshire, England, using the Rolling Stones Mobile Studio and the engineer Andy Johns, with the Stones' Ian Stewart assisting. Johns had just worked on engineering Sticky Fingers and recommended the mobile studio. The guitarist and producer Jimmy Page later recalled: "We needed the sort of facilities where we could have a cup of tea and wander around the garden and go in and do what we had to do." This relaxed, atmospheric environment at Headley Grange also provided other advantages for the band, as they were able to capture spontaneous performances immediately, with some tracks arising from the communal jamming. The bassist and keyboardist John Paul Jones remembered there was no bar or leisure facilities, but this helped focus the group on the music without being distracted.

Once the basic tracks had been recorded, the band added overdubs at Island Studios in February. The band spent five days at Island, before Page then took the multitrack tapes to Sunset Sound in Los Angeles for mixing on 9 February, on Johns' recommendation, with a plan for an April 1971 release. Mixing would take ten days, before Page travelled back to London with the newly mixed material. The band had a playback at Olympic Studios. The band disliked the results, and so after touring through the spring and early summer, Page remixed the whole album in July. The album was delayed again over the choice of cover and whether it should be a double album, with a possible suggestion it could be issued as a set of EPs.

Side one
"Black Dog" was named after a dog that hung around Headley Grange during recording. The riff was written by Page and Jones, while the a cappella section was influenced by Fleetwood Mac's "Oh Well". The singer Robert Plant wrote the lyrics, and later sang portions of the song during solo concerts. The guitar solos on the outro were recorded directly into the desk, without using an amplifier.

"Rock and Roll" was a collaboration with Stewart that came out of a jam early in the recording sessions at Headley Grange. The drummer John Bonham wrote the introduction, which came from jamming around the intro to Little Richard's "Keep A-Knockin'". The track became a live favourite in concert, being performed as the opening number or an encore. It was released as a promotional single in the US, with stereo and mono mixes on either side of the disc.

"The Battle of Evermore" was written by Page on the mandolin, borrowed from Jones. Plant added lyrics inspired by a book he was reading about the Scottish Independence Wars. The track features a duet between Plant and Fairport Convention's Sandy Denny, who provides the only female voice to be heard on a Led Zeppelin recording. Plant played the role of narrator in the song, describing events, while Denny sang the part of the town crier representing the people.

"Stairway to Heaven" was mostly written by Page, and the bulk of the chord sequence was already worked out when recording started at Basing Street Studios. The lyrics were written by Plant at Headley Grange, about a woman who "took everything without giving anything back". The final take of the song was recorded at Island Studios after the Headley Grange session. The basic backing track featured Bonham on drums, Jones on electric piano and Page on acoustic guitar. The whole group contributed to the arrangement, such as Jones playing recorders on the introduction and Bonham's distinctive drum entry halfway through the piece. Page played the guitar solo using a Fender Telecaster he had received from Jeff Beck and had been his main guitar on the group's first album and early live shows. He put down three different takes of the solo and picked the best to put on the album.

The song was considered the standout track on the album and was played on FM radio stations frequently, but the group resisted all suggestions to release it as a single. It became the centrepiece of the group's live set from 1971 onwards; in order to replicate the changes between acoustic, electric and twelve-string guitar on the studio recording, Page played a Gibson EDS-1275 double-neck guitar during the song.

Side two
"Misty Mountain Hop" was written at Headley Grange and featured Jones playing electric piano. Plant wrote the lyrics about dealing with the clash between students and police over drug possession. The title comes from J. R. R. Tolkien's The Hobbit. Plant later performed the track on solo tours.

"Four Sticks" took its title from Bonham playing the drum pattern that runs throughout the song with four drum sticks, and Jones played analog synth. The track was more difficult to record than the other material on the album, requiring numerous takes. It was played live occasionally in early 1971. The song was also re-recorded with the Bombay Symphony Orchestra in 1972. This version appears on the deluxe edition reissue of the group's 1982 album Coda. The song was also reworked for Page and Plant's 1994 album No Quarter: Jimmy Page and Robert Plant Unledded.

"Going to California" is a quiet acoustic number. It was written by Page and Plant about Californian earthquakes, and trying to find the perfect woman. The music was inspired by Joni Mitchell, of whom both Plant and Page were fans. The track was originally titled "Guide To California"; the final title comes from the trip to Los Angeles to mix the album.

"When the Levee Breaks" comes from a blues song recorded by Memphis Minnie and Kansas Joe McCoy in 1929. The track opens with Bonham's heavy unaccompanied drumming, which was recorded in the lobby of Headley Grange using two Beyerdynamic M 160 microphones which were hung up a flight of stairs; output from these were passed to a limiter. A Binson Echorec, a delay effects unit, was also used. Page recalled he had tried to record the track at early sessions, but it had sounded flat. The unusual locations around the lobby gave the ideal ambience for the drum sound. This introduction was later extensively sampled for hip hop music in the 1980s. Page and Plant played the song on their 1995 tour promoting No Quarter: Jimmy Page and Robert Plant Unledded.

Other songs
Three other songs from the sessions, "Down by the Seaside", "Night Flight" and "Boogie with Stu" (featuring Stewart on piano), were included four years later on the double album Physical Graffiti. An early version of "No Quarter" was also recorded at the sessions.

Title
After the lukewarm, if not confused and sometimes dismissive, critical reaction Led Zeppelin III had received in late 1970, Page decided that the next Led Zeppelin album would not have a title, but would instead feature four hand-drawn symbols on the inner sleeve and record label, each one chosen by the band member it represents. The record company were strongly against the idea, but the group stood their ground and refused to hand over the master tapes until their decision had been agreed to.

Page has also stated that the decision to release the album without any written information on the album sleeve was contrary to strong advice given to him by a press agent, who said that after a year's absence from both records and touring, the move would be akin to "professional suicide". Page thought, "We just happened to have a lot of faith in what we were doing." He recalled the record company were insisting that a title had to be on the album, but held his ground, as he felt it would be an answer to critics who could not review one Led Zeppelin album without a point of reference to earlier ones.

Releasing the album without an official title has made it difficult to consistently identify. While most commonly called Led Zeppelin IV, Atlantic Records catalogues have used the names Four Symbols and The Fourth Album. It has also been referred to as ZoSo (which Page's symbol appears to spell), Untitled and Runes. Page frequently refers to the album in interviews as "the fourth album" and "Led Zeppelin IV", and Plant thinks of it as "the fourth album, that's it". The original LP also has no text on the front or back cover, and lacks a catalogue number on the spine.

Cover
In place of a title, Page decided each member could choose a personal emblem for the cover. Initially thinking of a single symbol, he then decided there could be four, with each member of the band choosing his own. He designed his own symbol and has never publicly disclosed any reasoning behind it. It has been argued that his symbol appeared as early as 1557 to represent Saturn. The symbol is sometimes referred to as "ZoSo", though Page has explained that it was not in fact intended to be a word at all. Jones' symbol, which he chose from Rudolf Koch's Book of Signs, is a single circle intersecting three vesica pisces (a triquetra). It is intended to symbolise a person who possesses both confidence and competence. Bonham's symbol, the three interlocking (Borromean) rings, was picked by the drummer from the same book. It represents the triad of mother, father and child, but, also happens to be the logo for the steel and armament producer Krupp and, turned upside down, Ballantine beer. Plant's symbol of a feather within a circle was his own design, being based on the sign of the supposed Mu civilisation. A fifth, smaller symbol chosen by guest vocalist Sandy Denny represents her contribution to "The Battle of Evermore"; the figure, composed of three equilateral triangles, appears on the inner sleeve of the LP, serving as an asterisk.

During Led Zeppelin's tour of the United Kingdom in winter 1971 shortly after the album's release, the symbols could be seen on the group's stage equipment; Page's on one of his amplifiers, Bonham's on his bass drum head, Jones' on a covering for his Rhodes piano, and Plant's on the side of a PA cabinet. Only Page's and Bonham's symbols were retained for subsequent tours.

The picture on the front of the album of an old man carrying a bundle of sticks on his back was bought in an antique shop in Reading, Berkshire by Plant. The picture was then affixed to the internal, papered wall of a partly demolished suburban house for the cover photograph to be taken. Research in 2023 suggests that the image, which had previously been described as an oil painting, is a black and white photograph dating to 1892 which had been hand-coloured. The original photograph was taken by Ernest Howard Farmer (1856 – 1944), the first head of the school of photography at Regent Street Polytechnic. The research also suggests that the stooped figure is Lot Long (or Lot Longyear, 1823–1893), a thatcher from Mere, Wiltshire.

The block of flats seen on the album is Salisbury Tower in the Ladywood district of Birmingham. Page has explained that the cover of the fourth album was intended to bring out a city/country dichotomy that had initially surfaced on Led Zeppelin III, and a reminder that people should look after the Earth. He later said the cover was supposed to be for "other people to savour" rather than a direct statement. The album cover was among the 10 chosen by the Royal Mail for a set of "Classic Album Cover" postage stamps issued in January 2010.

The inside illustration, entitled "The Hermit", painted by Barrington Coleby (credited to Barrington Colby MOM on the album sleeve), was influenced by the design of the card of the same name in the Rider–Waite tarot deck. This character was later portrayed by Page himself in Led Zeppelin's concert film, The Song Remains the Same (1976). The inner painting is also referred to as View in Half or Varying Light. The typeface for the lyrics to "Stairway to Heaven", printed on the inside sleeve of the album, was Page's contribution. He found it in an Arts and Crafts magazine called The Studio which dated from the late 19th century. He thought the lettering was interesting and arranged for someone to create a whole alphabet.

Release
The album was released by Atlantic on 8 November 1971. It was promoted via a series of teaser advertisements showing the individual symbols on the album artwork. It entered the UK chart at No. 10, rising to No.1 the following week and has spent a total of 90 weeks on the chart. In the US it was Led Zeppelin's best-selling album, but did not top the Billboard album chart, peaking at No. 2 behind There's a Riot Goin' On by Sly and the Family Stone and Music by Carole King. "Ultimately", writes Lewis, "the fourth Zeppelin album would be the most durable seller in their catalogue and the most impressive critical and commercial success of their career". At one point, it was ranked as one of the top five best-selling albums of all time. The album is one of the best-selling albums of all time with more than 37 million copies sold as of 2014. As of 2021, it is tied for fifth-highest-certified album in the US by the Recording Industry Association of America at 24× Platinum.

The album was reissued several times throughout the 1970s, including a lilac vinyl pressing in 1978, and a box set package in 1988. It was first issued on CD in the 1980s. Page remastered the album in 1990 with engineer George Marino in an attempt to update the catalogue, and several tracks were used for that year's compilation Led Zeppelin Remasters and the Led Zeppelin Boxed Set. All remastered tracks were reissued on The Complete Studio Recordings, while the album was individually reissued on CD in 1994.

A remastered version of Led Zeppelin IV was reissued on 27 October 2014, along with Houses of the Holy. The reissue comes in six formats: a standard CD edition, a deluxe two-CD edition, a standard LP version, a deluxe two-LP version, a super deluxe two-CD plus two-LP version with a hardback book, and as high-resolution 24-bit/96k digital downloads. The deluxe and super deluxe editions feature bonus material. The reissue was released with an inverted colour version of the original album's artwork as its bonus disc's cover. The album's remastered version received widespread acclaim from critics, including Rolling Stone, who found Page's remastering "illuminative".

Critical reception
Led Zeppelin IV received overwhelming praise from critics. In a contemporary review for Rolling Stone, Lenny Kaye called it the band's "most consistently good" album yet and praised the diversity of the songs: "out of eight cuts, there isn't one that steps on another's toes, that tries to do too much all at once." Billboard magazine called it a "powerhouse album" that has the commercial potential of the band's previous three albums. Robert Christgau originally gave Led Zeppelin IV a lukewarm review in The Village Voice, but later called it a masterpiece of "heavy rock". While still finding the band's medieval ideas limiting, he believed the album showed them at the pinnacle of their songwriting, and regarded it as "the definitive Led Zeppelin and hence heavy metal album".

In a retrospective review for AllMusic, Stephen Thomas Erlewine credited the album for "defining not only Led Zeppelin but the sound and style of '70s hard rock", while "encompassing heavy metal, folk, pure rock & roll, and blues". In his album guide to heavy metal, Spin magazine's Joe Gross cited Led Zeppelin IV as a "monolithic cornerstone" of the genre. BBC Music's Daryl Easlea said that the album made the band a global success and effectively combined their third album's folk ideas with their second album's hard rock style, while Katherine Flynn and Julian Ring of Consequence of Sound felt it featured their debut's blues rock, along with the other styles from their second and third albums. Led Zeppelin's Rock and Roll Hall of Fame biography described the album as "a fully realized hybrid of the folk and hard-rock directions". PopMatters journalist AJ Ramirez regarded it as one of the greatest heavy metal albums ever, while Chuck Eddy named it the number one metal album of all time in his 1991 book Stairway to Hell: The 500 Best Heavy Metal Albums in the Universe. According to rock scholar Mablen Jones, Led Zeppelin IV and particularly "Stairway to Heaven" reflected heavy metal's presence in countercultural trends of the early 1970s, as the album "blended post-hippie mysticism, mythological preoccupations, and hard rock".

Steven Hyden observed in 2018 that the album's popularity had given rise to a reflexive bias against it from both fans and critics. "There are two unwritten laws" about the album, he wrote. The first was that a listener must claim a track from side two, the "deep cuts with credibility" side, was his or her favourite, and the second was that one should never say it was their favourite among the band's albums. He blamed this later tendency for why "rock critics who try too hard always make a case for In Through the Out Door being Zeppelin's best." The band members themselves, he noted, also seemed to prefer performing the songs from side two in their solo shows.

Accolades
In 2000, Led Zeppelin IV was named the 26th-greatest British album in a list by Q magazine. In 2002, Spin magazine's Chuck Klosterman named it the second-greatest metal album of all time and said that it was "the most famous hard-rock album ever recorded" as well as an album that unintentionally created metal—"the origin of everything that sounds, feels, or even tastes vaguely metallic". In 2000 it was voted number 42 in Colin Larkin's All Time Top 1000 Albums. In 2003, the album was ranked number 66 on Rolling Stone magazine's list of "The 500 Greatest Albums of All Time", then re-ranked number 69 in a 2012 revised list, and re-ranked 58 in a 2020 revised list. It was also named the seventh-best album of the 1970s in a list by Pitchfork. In 2016, Classic Rock magazine ranked Led Zeppelin IV as the greatest of all Zeppelin albums.

 * designates unordered lists.

Personnel
Led Zeppelin
 * Robert Plant – vocals, harmonica
 * Jimmy Page – electric and acoustic guitars, mandolin on "The Battle of Evermore", production, mastering, digital remastering
 * John Paul Jones – bass, electric piano, mandolin, recorders, synthesiser
 * John Bonham – drums

Additional musicians
 * Sandy Denny – duet vocals on "The Battle of Evermore"
 * Ian Stewart – piano on "Rock and Roll"

Production
 * George Chkiantz – mixing
 * Andy Johns – engineering, mixing
 * Peter Grant – executive production
 * Barrington Colby M.O.M. – The Hermit illustration
 * Keith Morris – photography
 * Graphreaks – design coordination

title: Led Zeppelin IV


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Houses of the Holy

Houses of the Holy is the fifth studio album by the English rock band Led Zeppelin, released on 28 March 1973 in the United States and on 30 March 1973 in the United Kingdom by Atlantic Records. The album benefited from two band members installing studios at home, which allowed them to develop more sophisticated songs and arrangements and expand their musical style. Several songs subsequently became fixtures in the group's live set, including "The Song Remains the Same", "The Rain Song" and "No Quarter". Other material recorded at the sessions, including the title track, was shelved and released on the later albums Physical Graffiti (1975) and Coda (1982). All instruments and vocals were provided by the band members Robert Plant (vocals), Jimmy Page (guitar), John Paul Jones (bass, keyboards), and John Bonham (drums). The album was produced by Page and mixed by Eddie Kramer. The cover was the first for the band to be designed by Hipgnosis and was based on a photograph taken at Giant's Causeway in Northern Ireland.

Although critical response was mixed, Houses of the Holy became a commercial success, later receiving a Diamond certification by the Recording Industry Association of America (RIAA) in 1999 for at least 10 million copies sold in the US. In 2020, the album was ranked at number 278 on Rolling Stone's 2020 list of the "500 Greatest Albums of All Time".

Recording
By 1972, Led Zeppelin had achieved sustained commercial and critical success from both their studio albums and live shows. They were keen to record on location using the Rolling Stones Mobile Studio as it had been an enjoyable experience for their untitled fourth album, released the previous year. After touring Australia, in April 1972 the group decided to take the mobile studio to Mick Jagger's home, Stargroves, a manor house and country estate in Hampshire. Eddie Kramer returned as recording engineer.

Some songs from the album had initially been tried out in earlier sessions, such as "No Quarter", which was first attempted during a session at Headley Grange Estate, in East Hampshire. Both guitarist and producer Jimmy Page and bassist / keyboardist John Paul Jones had installed home studios, which allowed them to arrive at Stargroves with complete compositions and arrangements.

Page's home studio used some of the equipment from Pye Mobile Studios, which had been used to record the Who's 1970 live album Live at Leeds. Because of his home studio, he was able to present a complete arrangement of "The Rain Song", including non-standard guitar tunings and a variety of dynamics, and "Over the Hills and Far Away", featuring multiple guitar parts. Meanwhile, Jones had developed a new arrangement of "No Quarter". Once the group were settled in Stargroves, they composed the other songs through jam sessions together. Further recording took place at Olympic Studios in May, and during the band's 1972 North American tour additional recording sessions were conducted at Electric Lady Studios in New York. Some songs recorded during these various sessions did not make it onto Houses of the Holy, though several were released on later albums. A series of rock 'n' roll covers, including songs that appeared on Elvis Presley's Elvis' Golden Records, were recorded at Electric Lady Studios, which remain unreleased.

Composition
The album was a stylistic turning point for the band. The composition and production laid foundations for subsequent releases. According to the band's biographer Dave Lewis, "while the barnstorming effect of the early era was now levelling off, and though devoid of the electricity of Zeppelin I and II, the sheer diversity of the third album, and lacking the classic status of the fourth, Houses of the Holy nevertheless found its rightful niche." The album largely abandoned their previous music's weighty, dark blues rock distortion in favor of a clean, expansive rock sound—as evinced by Page's sharper, brighter guitar tone. It was also likely the most eclectic musically of their albums, in the opinion of Consequence of Sound writer Kristofer Lenz, who observed swing rhythms on "Dancing Days", and experiments with reggae and psychedelic music on "D'Yer Mak'er" and "No Quarter", respectively. Pete Prown and HP Newquist have called it "a diverse collection of rockers, ballads, reggae, funk, and fifties-style rock 'n' roll".

Side one
The album's opening track, "The Song Remains The Same", was originally a Page-composed instrumental called "The Overture". Plant added lyrics that referred to the group's experiences on tour, and it was given a working title of "The Campaign". His lead vocal was sped up slightly in the final mix, while Page played an electric twelve string guitar and a six-string electric. For live performances, he used the Gibson EDS-1275 double-neck guitar that was also used for playing "Stairway to Heaven" in concert.

"The Rain Song" was composed at Page's home studio, including the entire arrangement and the vocal melody. He was inspired to write the song after George Harrison complained that Led Zeppelin "never did any ballads". The opening chords are the same as Harrison's song “Something” from The Beatles' Abbey Road. The backing track was recorded at Olympic, with a working title of "Slush". Plant added some sensitive lyrics which matched the music, Jones added a string section played on the Mellotron, while Page played acoustic and Danelectro electric guitars in various different tunings. The song was regularly performed live, with Page using the Gibson EDS-1275. Page and Plant revived the track for their 1994–95 tour.

"Over the Hills and Far Away" was written about the hippie lifestyle, including references to the "open road". The song was developed in two halves, with a quiet acoustic section leading into a livelier electric one. The song was one of the first to be introduced into Led Zeppelin's live set, being first played in mid-1972.

"The Crunge" was written by Bonham and developed out of a jam at Stargroves. He decided to create a funk beat that stepped on and off the beat, making it impossible to dance to. Plant improvised a set of lyrics in the manner of James Brown over the music, parodying Brown's "Take it to the Bridge" vocal style towards the end of the track. To further show that the song was a tongue-in-cheek joke, the group considered putting "dance steps" to the song on the cover at one stage. The track was occasionally performed as an impromptu piece in concert, usually in the middle of another song such as the fast guitar solo section in "Dazed and Confused".

Side two
"Dancing Days" was inspired by the enjoyable sessions at Stargroves, and the lyrics show a general optimism to life. Kramer recalled the group dancing around in the garden at Stargroves, listening to the playback of the final mix. A promotional copy of the track was sent out by Atlantic for radio play in March 1973, as a preview for the album.

"D'yer Mak'er" originated with Bonham trying to combine reggae with 1950s doo-wop by leaving a short off-beat. Jones later disapproved of the track, saying it was treated as a joke and not thought out well, but Plant thought it could be a hit and suggested it should be released as a single. Led Zeppelin's general policy was to not release singles in the UK, and though test and promotional pressings were produced there, the rest of the group vetoed the idea. In the United States, it became a top 20 hit.

"No Quarter" was composed by Jones. An early arrangement of the song was attempted for their fourth album, but abandoned. Jones reworked the track to add acoustic and electric piano, and various synthesizers. The track quickly became a live favourite, and was featured at every show from 1973 through 1979, providing Jones with an extended solo showcase in the middle, and a jam session with a variety of different styles. Plant revived the song for his 1990 tour, and it was performed by Page and Plant in 1994. Jones performed a solo instrumental performance on tour in 1999, and Plant performed it solo again in 2005. It was part of the set at the Ahmet Ertegun Tribute Concert in 2007.

"The Ocean" began with Bonham shouting "We've done four already but now we're steady and then they went, one, two, three, four," referring to the number of takes already recorded. The title and lyrics refer to the group's fans and their devotion to the band. The middle of the track features an a cappella vocal break sung by Plant, Bonham and Jones, while the ending was another pastiche of the doo-wop style.

Unreleased material
The album's title track was recorded at Olympic and mixed at Electric Lady. It was ultimately left off the album, as there were enough tracks to fill two sides of an LP, and was released on the follow-up, Physical Graffiti in 1975. That album also included two songs from Houses of the Holy's Stargroves sessions, "The Rover" and "Black Country Woman" (the latter recorded in the outdoor garden).

Another track from the Stargroves sessions, "Walter's Walk", was eventually released on Coda in 1982.

Packaging

Houses of the Holy was the first album by the group to have an explicit title that was not eponymous, but like the previous one, neither the band's name nor the album title was printed on the sleeve. However, manager Peter Grant did allow Atlantic Records to add a wrap-around paper title band to US copies of the sleeve that had to be broken or slid off to access the record. The first CD release of the album in the 1980s had the title logos printed on the cover itself.

The cover art for Houses of the Holy was inspired by Arthur C. Clarke's novel Childhood's End. The cover is a collage of several photographs which were taken at the Giant's Causeway, Northern Ireland, by Aubrey Powell of Hipgnosis. This location was chosen ahead of an alternative one in Peru which had also been considered.

The photo shoot featured two naked child models, Stefan and Samantha Gates. It was a frustrating affair over the course of 10 days. Shooting was done first thing in the morning and at sunset in order to capture the light at dawn and dusk, but the desired effect was never achieved due to constant rain and clouds. The photos of the two children were taken in black and white and were multi-printed to create the effect of 11 individuals that can be seen on the album cover. The results were unsatisfactory, but some accidental tinting effects in post-production created a suitable cover. The inner gatefold photograph was taken at Dunluce Castle nearby the Causeway. In February 2010, Stefan Gates was featured on a BBC Radio 4 documentary about the cover. He said there was something sinister about the image, though his sister disagreed. He also admitted never having heard the album. The programme ended with Gates returning to Giant's Causeway and listening to the album on a portable player, after which he said that a great weight had been lifted from him. Samantha also appeared on the back cover of the band's 1976 album Presence.

Page has stated that the album cover was the second version submitted by Hipgnosis. The first, by artist Storm Thorgerson, featured an electric green tennis court with a tennis racket on it. Furious that Thorgerson was implying, by means of a visual pun, that their music sounded like a "racket", the band fired him and hired Powell in his place.

In 1974, the album was nominated for a Grammy Award in the category of Best Album Package. The cover was rated number 6 on VH1's 50 Greatest Album Covers in 2003.

Release and reception
This was Led Zeppelin's final studio release on Atlantic Records before forming their own label, Swan Song Records, in 1974, which would be distributed by Atlantic. It was also the only Led Zeppelin album that contained complete printed lyrics for each song.

Although intended for release in January 1973, delays in producing the album cover meant that it was not released until March, when the band was on its 1973 European tour. The album was promoted heavily before the commencement of Led Zeppelin's subsequent North American Tour, ensuring that it had ascended the top of the American chart by the beginning of the tour. Because much of the album had been recorded almost a year previously, many of the songs which are featured on the album had already been played live by Led Zeppelin on their concert tours of North America, Japan, Europe and the UK in 1972–73.

Houses of the Holy originally received mixed reviews, with much criticism from the music press being directed at the off-beat nature of tracks such as "The Crunge" and "D'yer Mak'er". Gordon Fletcher from Rolling Stone called the album "one of the dullest and most confusing albums I've heard this year", believing the band had digressed from "the epitome of everything good about rock" to a watered down heavy metal act. However, the album was a commercial success and topped the UK charts and spent 39 weeks on the Billboard 200 albums chart including two weeks at number one (their longest stint since Led Zeppelin III). The album was number four on Billboard magazine's top albums of 1973 year end chart.

In Christgau's Record Guide: Rock Albums of the Seventies (1981), Robert Christgau appraised Houses of the Holy favourably. While mocking the solemnity of "No Quarter" and finding some tracks derivative of previous albums, he found side one "solid led" with "sprung rhythm" and a "James Brown tribute/parody/ripoff" in "The Crunge" that complements the second side's "two amazing, well, dance tracks" in "Dancing Dayss "transmogrified shuffle" and the reggae of "D'yer Mak'er". "Throughout the record, the band's playing is excellent," wrote AllMusic's Stephen Thomas Erlewine, "making the eclecticism of Page and Robert Plant's songwriting sound coherent and natural."

In 2003, Rolling Stone ranked it at number 149 on the magazine's list of the "500 Greatest Albums of All Time." It was re-ranked at number 148 in a 2012 revised list, and re-ranked at number 278 in 2020.

(*) designates unordered lists.

2014 reissue
A remastered version of Houses of the Holy was reissued on 27 October 2014, along with Led Zeppelin IV. The reissue comes in six formats: a standard CD edition, a deluxe two-CD edition, a standard LP version, a deluxe two-LP version, a super deluxe two-CD plus two-LP version with a hardback book, and as high resolution 24-bit/96k digital downloads. The deluxe and super deluxe editions feature bonus material. The reissue was released with an altered-colour version of the original album's artwork as its bonus disc's cover.

At Metacritic, which assigns a normalised rating out of 100 to reviews from mainstream publications, the reissue received an average score of 98, based on nine reviews, indicating "universal acclaim". Consequence of Sound writer Kristofer Lenz said, "The remastering of this album is a blessing to the careful compositions and mannered performances throughout the record." "Houses of the Holy might be Zeppelin's most impressive album on a purely sonic level," wrote Pitchfork's Mark Richardson, "and this particular remaster reinforces that notion." He was disappointed, however, by the bonus disc of alternate mixes, which merely provide "a chance to hear familiar performances in familiar songs in a way that sounds slightly unfamiliar".

Track listing
All tracks composed by Jimmy Page and Robert Plant, except where noted.

Personnel

 * Led Zeppelin
 * Robert Plant – vocals
 * Jimmy Page – guitars, production
 * John Paul Jones – bass guitar, piano, Mellotron, organ, synthesiser, backing vocals on "The Ocean"
 * John Bonham – drums, backing vocals on "The Ocean"

 * Production
 * Eddie Kramer – engineering, mixing
 * George Chkiantz – engineering
 * Keith Harwood – engineering
 * George Marino – mastering (remastered CD)

 * Design and cover
 * Hipgnosis – sleeve design
 * Aubrey Powell – cover photography

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Houses of the Holy


text:
Talk:Piezoelectricity

Electron microscopes
There is no reference to the use of Piezoelectrics in Scanning Tunneling Microscopes and similar instruments although the article mentions its use in Optical Instruments. - Torris 10/18/2006

US vs Japan research methods
I'm confused by the philosophical discussion about U.S. research methods v.s. Japanese research methods. Isn't this an article about piezoelectricity?

This paragraph is not about philosophy or research methods, but possibly an example of how legislation like patent laws, military secrecy, and other regulations on the free flow of information may interfere with a society’s ability to derive technology from a physical fact. If this is verifiable the paragraph should be rewritten with stronger focus on this aspect and carry references to other existing articles discussing the same problem. --EugenNJ 13:40, 14 February 2007 (UTC)

Voltage or current?
Shouldn't the definition be about stress-induced voltage rather than current? I would assume that most crystals don't have many free electrons, so it's not clear how they could generate much of a current. Voltage however is clear: you take a crystal with symmetrical charge distribution, the stress creates an asymmetrical charge distribution which is the same as a voltage. AxelBoldt, Wednesday, April 24, 2002

 * Is this why it happens? If so, it would be good to put that in the article explained in a bit more detail.  As it is, there is no explanation of why the piezoelectric effect happens, only a description of it.  128.118.68.50 20:41, 7 July 2006 (UTC)

One more question connected with this is whether a "constant stress" leads to "constant voltage" from a peizoelectric material? There are lot of examples of vibrations, ultrasound etc which convey the meaning that a constant voltage from a battery applied to a peizo will result in a "vibration". This seems contrary to the definition of peizoelectric effect as stated. Could you kindly correct this. (144.189.5.201 12:39, 27 December 2006 (UTC))
 * Constant stress, T, leads to constant electric displacement, D, as in: Di=dij Tj + epislonij Ej.  Electric displacement is related to the charge induced on the surface of the material.  A battery applied to a piezo will not result in a vibration, unless the battery's output is converted into an A.C. signal.  Ultrasonic output can be generated if this A.C. signal has a frequency in the ultrasound range.  --Nathaniel 02:47, 17 January 2007 (UTC)

Name and redirects
Piezoelectric effect redirects to piezoelectricity, and pyroelectric effect redirects to pyroelectricity, but ferroelectricity redirects to ferroelectric effect. These should all be consistent. The "-ity" sounds rather odd to me, and I think " effect" is better. Any opinions? –radiojon 15:02, 2004 Apr 16 (UTC)

 * I agree that we should be consistent. There is probably a subtle difference between the "x effect" and "x-electricity", so we need to record both forms somehow.  I would say that the "x effect" is an abstract concept meaning "the process by which e.g. squeezing a crystal creates electricity", while "x-electricity" is a concrete thing, the electricity that you get as the result of the effect.  I think this means that the title of the article should be the "x effect", as you said above, but let's acknowledge the existence of the "x-electricity" form somewhere in each article. -- Heron 15:29, 5 Jul 2004 (UTC)

 * Well, actually it is not that straightforward, because for the case of ferromagnetism, we would need to have ferromagnetic effect (for which the page does not exist) redirecting to magnetism. Incidentally, ferroelectricity (electric dipoles) is the analogue of ferromagnetism (magnetic dipoles). --Nathaniel 02:27, 17 January 2007 (UTC)

pronunciation
everyone pronounces it differently. there are two "proper" ways:

 * pie ee zoe
 * pee ay zoe

http://www.bartleby.com/61/59/P0295900.html

and it is not named after someone, as i heard somewhere:

From Greek piezein, to press tight, squeeze. See sed- in Indo-European Roots.

- Omegatron 15:23, Oct 15, 2004 (UTC)

- THIS SHOULD BE IN THE MAIN WIKIPEDIA ENTRY AS IT IS SO OFTEN MISPRONOUNCED!!! I tried putting in there but someone took it out :(

I agree. I mostly hear pee-zoe and sometimes pee-ay-zoe or pee-etzoe. Never heard pie-ee-zoe. 93.97.48.217 (talk) 20:14, 24 April 2009 (UTC)

piezoelectricity on a small scale
Can someone who knows include information on how small the materials can be made and still create a voltage differential under pressure? For instance, can piezoelectric sensors be made small enough and sensitive enough to record the impact of a single gas molecule on the surface of the sensor? --Flatline 12:39, August 4, 2005 (UTC)

I think this issue is at the forefront of research in ferroelectric (and presumably piezoelectric) crystals. Here is an interesting article: Unusual phase transitions in ferroelectric nanodisks and nanorods, Ivan I. Naumov, L. Bellaiche, and Huaxiang Fu, Nature (London) 432, 737 (2004). --User:huckit

Piezoelasticity?
I just searched Wikipedia and found no reference yet to the related subject of piezoelasticity. It would be useful to add a section to the main article. Likewise, no reference yet to another related term electroelastic. DFH 15:18:55, 2005-09-06 (UTC)

I could not find both the terms piezoelastic/piezoelasticity and electroelastic/electroelasticity in the dictionary. Are you sure these terms exist? Perhaps the term "electroactive" should be used for electroelastic? EAP is the abbreviation for electroactive polymers, of which PVDF is an example. See and. Nathaniel 09:09, 23 September 2005 (UTC)

I don't know if it helps, but the correct term might be ferroelasticity. The piezoelectric effect couples the mechanical and electrical domains- so the terms 'piezoelasticity' and 'electroelasticity' (which I don't believe exist), might be referring to the direct and converse piezoelectric effect. Of course there is electrostriction, which is exhibited by all ferroelectric materials... this is

 * Hi! All the words you have written can be used: "electroelasticity" is quite used in mechanics. It simply means the coupling of electric and mechanical effects, so we don't need another article. Ceccorossi 16:37, 25 April 2007 (UTC)

 * As a person with no electrical/physical knowledge, I have the same problem as the original poster. I got here from "piezoelasticity" and I still don't know what it means. The article should at least mention the word, even if it only says "this is a synonym for (some other word)". 86.130.40.127 (talk) 23:11, 27 December 2013 (UTC)
 * I've not heard of "piezoelasticity" before but it sounds like a near synonym of "elasticity". Judging from its name, a piezoelastic material would be one that responds elastically (presumably as opposed to plastically) to pressure.  Nothing to do with piezoelectricity in other words, which means it should not redirect here. Dondervogel 2 (talk) 00:24, 28 December 2013 (UTC)

"PZT"
PZT is mentioned in the first paragraph of this article. What is it?

 * PZT could be lead zirconium titanate, a ceramic. --Yyy 15:20, 17 November 2005 (UTC)

 * Yes, that's correct. I have updated the link.  PZT is a ceramic made from a combination of powders of PbO2, ZrO2, and TiO2 (hence PZT) in a certain ratio of about 0.52:0.48 of Zr:Ti to obtain the optimum piezoelectric effect.  The powders have to be mixed & heated to a certain temperature to get them to form the new structure (the perovskite structure) of PZT--calcination & sintering. Nathaniel 07:46, 18 November 2005 (UTC)

The deformation for PZT is given as "of the order of nanometers." This is often true in MEMS (MicroElectroMechanical Systems). However, if the change is really 0.1% of the original dimension, then there is not a "typical" value for the deformation. If a deformation is to be given, the original dimension should be included as well.

 * It really needs to state the relevant conditions. When is it 0.1%?  How can a thin piezo buzzer generate very loud sound if only moving that much? — Omegatron 14:53, 24 October 2006 (UTC)

If particle displacement is found according to:

\xi = \frac{p}{Z \cdot \omega} $$

And Z for air is 410 Pa·s/m = 410 N·s/m3, and a buzzer on this page can generate 85 dB SPL at 2.3 kHz, the particle displacement should be:

85=20\, \log_{10}\left(\frac{p}{20 \mu Pa}\right)\mbox{ dB} $$

so p = 0.4 Pa

\omega = 2\pi 2300 = 14450 $$

so ω = 14450 rad/s

displacement is 67.5 nanometers. Huh. 120 dB SPL or 100 Hz would be more like a few microns, though. — Omegatron 15:23, 24 October 2006 (UTC)

Mathematical description
The tensorial description seems to have a typo (But an important one). Without being an expert, all the literature that I have checked so far gives the following expression for the coupled equations: $$ \begin{align} \boldsymbol{S} &= \mathsf{s}\,\boldsymbol{T} \color{red}{-} \mathfrak{d}^t\,\mathbf{E} \\ \mathbf{D} &= \mathfrak{d}\,\boldsymbol{T} + \boldsymbol{\varepsilon}\,\mathbf{E}. \end{align} $$ With a negative sign for the second term of the first equation, as opposed to having only positive signs as it shows currently on the entry. Am I missing something? (See, for instance: Kögl, M. and Gaul,L. Piezoelectric analysis with FEM and BEM 2001, in Smart Structures V. 429, Springer Vienna.) Belbojacopo (talk) 04:58, 23 August 2015 (UTC)
 * The negative sign occurs in the stress-charge form of the equations. The version in the article is the strain-charge form. Bbanerje (talk) 09:34, 24 August 2015 (UTC)

Matrices
While I have not studied this effect, looking at the matrices, it looks like there are several typos. For example, there is a s_{44}^E term where one would expect s_{55}^E. Likewise, there is a d_{31) term where one would expect there to be d_{32). Is this correct?
 * It is correct for only the 4mm and 6mm point groups. A more generalized matrix equation is probably better. Polaron | Talk 03:23, 1 July 2006 (UTC)
 * most commercial PZT materials fall into these point groups. So s_{12}^E=s_{21}^E, s_{44}^E=s_{55}^E, etc.  The generalized matrix equation can easily be created by removing all the zeros and putting back the constants 11, 12, 13, ... 21, 22, 23, ... 31, 32, 33...  However, the average person who is using such materials may want to know which constants are equal, which constants are equal to zero, etc.  I have made the change on the wikipedia site to indicate that the equations in this simplified form applies to the 6mm crystal class.  --Nathaniel 10:57, 29 July 2006 (UTC)

 * This section and the Crystal classes section need a little background info for the rest of us. — Omegatron 14:52, 24 October 2006 (UTC)

Confusion with Reverse Piezoelectric effect and Converse
In this article it states that the piezoelectric effect works in reverse (apply voltage and the crystal grows in size slightly). Then later on it states that "Piezoelectric materials also show the opposite effect, called converse piezoelectricity, where the application of an electrical field creates mechanical deformation in the crystal." Now, it is just me or do these two things sound extremely the same? Is there a difference between applying a volatage and applying an electrical field? I have heard about the Piezoelectric effect working in reverse, it is in fact published in the the book tittled "Crystals and Crystal Growing" a book published by the M.I.T. Press. Does anyone have any more information? If not, I am going to look into converse piezoelectric effect and if I do not find sufficient source then I may remove that bit of the article.
 * in the converse piezoelectric effect, you apply a voltage/electric field to create a deformation in the crystal. in the piezoelectric effect, you apply a deformation to the crystal and charge is generated on the surface of the crystal.  applying an electric field is carried out by applying a voltage to the surface of the piezoelectric crystal.  all piezoelectric materials exhibit both the piezoelectric effect and the converse piezoelectric effect.  --Nathaniel 11:01, 29 July 2006 (UTC)
 * I think the anon is asking if there's a difference between the "reverse" and "converse" effects. — Omegatron 13:53, 29 July 2006 (UTC)

 * Nowhere does this article refer to a 'reverse piezoelectric effect', which is a shame because that's what the OUP's A Dictionary of Physics calls it. However, there are lots of websites that, like ours, call it the 'converse piezoelectric effect'. I am sure that the two terms refer to the same thing. I don't see any confusion within our article, though - it consistently calls it the latter. --Heron 16:47, 29 July 2006 (UTC)
 * Difference between "reverse" and "converse". — Omegatron 14:50, 24 October 2006 (UTC)

"Piezoelectric materials also show the opposite effect, called inverse piezoelectricity, where the application of an electrical field creates mechanical deformation in the crystal." Is this the same as converse piezoelectricity or just a typographic mistake? Mingmasterz 00:21, 8 February 2007 (UTC)
 * Probably a typo, or at most a non-standard teminology. I have changed it to "converse." 134.67.6.11 12:22, 20 June 2007 (UTC)

Triboluminescence
How is this related to Triboluminescence? --Gbleem 09:05, 6 October 2006 (UTC)

 * I don't think they are very related. Triboluminescence involves breaking a crystal's asymmetrical bonds, creating an electric discharge due to the triboelectric effect?  Piezoelectricity involves a voltage generated by mechanically stressing a crystal without breaking any bonds. — Omegatron 14:48, 24 October 2006 (UTC)

Microphones
"Ceramic electret microphones could be made small and sensitive."

 * Electrets are not piezoelectric. Was piezoelectric microphone intended? — Omegatron 14:18, 24 October 2006 (UTC)

 * There's also a list of polymer electret materials. Why? — Omegatron 14:44, 24 October 2006 (UTC)

Flashing quartz Ute rattles
Is the flashing caused by triboluminescence (cracks in the crystal structure causing electrical discharges from the triboelectric effect) or from piezoelectricity (deformation of the crystal creating voltages and causing electrical discharges, like piezo ignition)? See Talk:Ute tribe for discussion. — Omegatron 04:03, 26 November 2006 (UTC)

Suggestions
I'm writing as a simple user, not in any way an expert. After reading this article I am still left with the following two questions:

- Could we get any simple conversion factors for the most common piezoelectric materials in usage to estimate the electric energy that could be harvested from a certain amount of applied force (for a given size - area or volume or both - of material)? And conversely, what amount of physical distortion can we expect from a given current applied?

- Does the piezoelectric effect - in this case electric energy from material stress - take place only while the material is being compressed, or also when it has been compressed and continues to lie in a stable state under continuous stress?

I will be grateful if someone could explain the above issues in the article.

-- Also, is there any relationship between crystal size/mass and electrical output? I assume the output of a large mass w/ small stress would be silimar to a small mass w/ large stress; is this correct? The math was over my head, but it seemed to me that mass wasn't part of any equation in the article. Could someone explain this(or the equations) in lay-terms please. Mingmasterz 01:14, 8 February 2007 (UTC)

"Ultrasonic transducers" section:
"When several elements are stacked upon each other and to the end a blade is placed we can drive the crystal and with the displacement achieved we will have an ultrasonic cutter. This kind of tool is useful when cutting plastic materials or similars as soft material doesn't get affected by the ultrasonic vibration; in fact the cut happens to a local melting of the material due to friction and no application of heat." I assume this is written by someone whose first language isn't english and knows nothing of grammar, punctuation or chosing the right words... could someone who knows what the heck they're trying to say rewrite this into decent english.--KX36 17:45, 17 March 2007 (UTC)

 * Plus, that's not a transducer; it's an actuator. I'm inclined to just delete it since it's not very informative and the statement about soft materials is factually questionable, in addition to being almost unintelligible. The gist is "stick a knife on a vibrating piezo and it chops". Tarchon 17:24, 25 April 2007 (UTC)

Factual Accuracy Dispute
What is the source of this dispute? Is there actually a dispute? Or is it merely the requirement of a citation...because honestly, I think that whole section should go and be redone. The whole reference to electrets seems foolish. Electrets have nothing to do with piezoelectricity and this section is misleading. I would prefer for someone to discuss more (I could...but would need some research first...I'll look back in my solid state physics books) the symmetry issue, as a long list of materials is somewhat foolish. Its such a wide range of materials. --Lagrangian 23:23, 23 April 2007 (PST)
 * Looking over the edit history, the "dispute" tag was added at the same time that the citation request was added. That whole materials section needs to be edited -- it's kind of a random collection. 75.45.75.65 22:43, 10 June 2007 (UTC)

Don't have time to discuss at the moment but J. Chem Ed. 2007 p. 12 has some useful info.

first Discovery of piezoelectricity ?
The french wiki says: The dicoverer of piezoelectricity is the monk René Just Haüy (1743-1822) in 1817, while studying spath of islande. True ? 20 may 2007
 * Damned good question. For what it's worth, I've always heard that the Curies discovered piezoelectricity.  After poking around some, I infer from a few places (Antoine César Becquerel and René Just Haüy, among others) that Haüy did some basic work in crystal effects related to piezoelectricity (pyroelectricity, for example), but may not have dealt with piezoelectricity per se.  However, I also find some places (like Britannica here that baldly state that Haüy did indeed discover piezoelectricity. 75.45.75.65 22:43, 10 June 2007 (UTC)
 * Here we go: : "...Hauy and Becquerel tried to find a relationship also between mechanical stress and electric polarization but the findings they reported were far from conclusive. The experimental setups at the time were always prone to be perturbed by the omnipresent triboelectricity (electric charge due to fristion) on the insulators, such as amber."
 * Ok thanks, I recently deleted that bit on French Wiki considering I could not find any relevant source. Reading this, I guess it would be worth trying to have a look at the original work by Haüy though. I might be interested in doing this, but somewhat later Tizeff 12:49, 31 August 2007 (UTC)
 * It is not easy to have access to the original work of Haüy in 1817. However I could find some more information in a recent book (Leçons de physique, de chimie et d'histoire naturelle - l'Ecole normale de l'an III, which can be considered as pretty reliable. This book notably cites the 1817 paper as well as a later book by the same author. I updated the article of French wiki accordingly . Tizeff 10:06, 8 November 2007 (UTC)
 * By the way, what's the source for the bit on David Brewster? 75.45.75.65 22:43, 10 June 2007 (UTC)

Force comment
I delected the following sentence: "The bending forces generated by converse piezoelectricity are extremely high, of the order of tens of millions of pounds (tens of meganewtons), and usually cannot be constrained. The only reason the force is usually not noticed is because it causes a displacement of the order of a few nanometers (billionth of an inch)." First of all the placement was rather odd; second (and more importantly) it's a bit misleading because scale is not discussed (and neither is macroscopic construction, although I suspect this refers to a single crystal). I have no particular objection to the thought being rewritten ans reinserted if anyone cares to. 134.67.6.11 12:17, 20 June 2007 (UTC)

Mechanism
I added a section called "Mechanism." I came to this page looking for why this effect happens, and found nothing until I noticed an explanation hiding in the "Crystal classes" section. Since I obviously don't know how this effect works, I don't know if that is a complete or accurate description of how or why crystals produce potential. I don't even know if "Mechanism" is the right term. However, what I did doesn't look bad, so I decided to be bold--if I did something wrong, it'll at least bring attention to this section. Twilight Realm (talk) 21:29, 11 December 2007 (UTC)

Diagram
What do you think about adding this diagram to the article? http://de.wikipedia.org/wiki/Bild:Piezoeffekt350px.gif --91.43.74.141 (talk) 13:20, 30 July 2008 (UTC)

Most common piezoelectric ceramic
The article states that PZT is the most common piezoelectric ceramic in use today. I am under the impression that it would be more correct to say that PZT is the most common man-made in use. As quartz is probably more widely used and is a piezoelectric ceramic. This is just a picky argument though.The Lamb of God (talk) 16:44, 15 September 2009 (UTC)

I thought quartz, though sometimes manmade, is not a ceramic! It is a single-crystal material, while, I think, ceramics are poly-crystalline. No? — Preceding unsigned comment added by 134.139.237.168 (talk) 01:57, 27 April 2012 (UTC)

Flint & Steel?
Is it an example of the piezoelectric effect? --64.81.149.67 (talk) 19:11, 15 June 2011 (UTC)

Sensor/actuator
There was an error in the "applications" section: the crystal earpieces were placed under "sensors", but they clearly are actuators, so I changed it's place... For the second time. So, please, don't change it back if you don't know what you're doing. Frlara (talk) 05:28, 9 July 2012 (UTC)

Constant stress producing DC electricity?
I am interested in the possibility of using piezoelectric devices under constant applied stress (such as compression under weight) as replacements for batteries. All the scientific studies I can find seem to be about the generation of AC from vibratory stresses, not DC from constant stress. Furthermore, the standard experimental protocol examines the deflection stress of a cantilevered beam, not compression stress.

If anybody comes across research pertaining to constant stress applied to piezoelectric devices to produce DC electricity, please add them as sources to this article. Dlw20070716 (talk) 03:42, 16 September 2013 (UTC)

 * Sorry to burst your bubble, but your idea is based on a false premise. A piezoelectric medium is a dielectric, this precludes a steady flow of current. The only thing that happens under static pressure is that the medium will electrically polarize. At that point, the device is like a charged capacitor, when you short it, current will flow, but after that in essence it is empty. Why: The charge will distribute itself over the plates in a way that will counterbalance the dielectric polarisation, so no field is left to drive a current (until you remove the pressure). - Snaily (talk) 07:38, 16 September 2013 (UTC)

Top Image
The image at the top of the page is currently "A_piezoelectric_system_(Without_contact_tabs)_2013-06-21_10-02.jpg", a photograph of a CRT monitor with an image of a portable CD player and, presumably, a piezoelectric speaker, with the caption: "A piezoelectric system (without contact tabs)." Surly there is a more representative image available. tbhartman (talk) 21:09, 8 January 2014 (UTC)

I concur. This is a terrible and ambiguous image for such a lengthy and important article. Dev Gualtieri 23 January 2014 —Preceding undated comment added 23:24, 23 January 2014 (UTC)

It's the effect not the charge!
Piezoelectricity is the effect wherein a voltage difference or electricity is generated due to applied mechanical stress. It isn't the charge produced. Piezoelectricity is at best the phenomenon, or the electricity generated. That does not equate to the charge produced. All sources I look at are consistent with my interpretation. I don't thave access to the cited book though. Opinions? Chandra.sarthak (talk) 10:01, 10 January 2016 (UTC)

I would agree that the article's wording is not quite correct. It's not quite 'charge is generated,' but I don't know how to phrase it exactly. Maybe a potential gradient or the aggregate of dipoles formed in the crystal? (75.80.54.216 (talk) 22:40, 8 July 2016 (UTC))

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I really don't understand nabla u + u nabla / 2
Sorry, I just don't understand. no link, no "Where u is" nothing to help someone who doesn't already recognize what you are saying. I understand the rest of it, but can't get that. — Preceding unsigned comment added by 173.252.8.222 (talk) 20:11, 3 May 2017 (UTC)

Piezoelectric Ignition
Piezoelectric Ignition systems have been used on gas stoves, both domestic and camping. 60.242.247.177 (talk) 01:49, 29 May 2017 (UTC)

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Artificial muscles
https://ieeexplore.ieee.org/abstract/document/680638 Elias (talk) 10:19, 23 April 2021 (UTC)

Vector image available
I've made an SVG version of File:Piezo bending principle.jpg but I haven't added it to the article yet. The original image seems to suggest that a voltage of the same polarity is produced when the piezo element is flexed in either direction. Is this actually correct? Please compare the two images below and let me know if the SVG needs to be changed. You'll notice that I've reversed the polarity in the lower part of the image; I can change this back easily enough if necessary.

SVG (Piezo bending principle.svg)

If the SVG looks OK, then please go ahead and insert it into the article. 忍者猫 (talk) 15:28, 17 February 2022 (UTC)

 * Update: I'll go ahead and change the image. According to the illustrations at piezo.com, the polarity does change between compression and tension, so the JPEG illustration is incorrect. However, it looks like I got the plus and minus symbols the wrong way round. Now fixed. -- 忍者猫 (talk) 07:12, 2 August 2022 (UTC)

Current application details
So, up the page someone asked (Constant Stress DC...) about the current that results from a piezo device, and the question clearly results from a lack of discussion of the basic electric details of the application of the device. It would be useful to provide such a basic description: the device generates an electric potential when compressed. That can then be used to drive a current; as the responder above said, it is like charging and discharging a capacitor. This should be noted in the article. And further, what then happens when the crystal is compressed, but discharged? Does the discharge affect the degree of compression of the crystal? Is there a reverse voltage that happens then when pressure is then released? Will voltage not build up again while pressure is left applied? So many questions arise about practical application which this article doesn't address at all. A phys.org article on piezos says the standard unit for measure of merit for piezo materials is "picocoulombs/newton". The article says nothing about this. 2001:56A:F0E9:9B00:70C9:8143:900D:6088 (talk) 18:56, 18 May 2022 (UTC)JustSomeWikiReader

Japan Vs USA thing
A source could be cool because It feels someone pulled it out of their ass. What about talking about european developments too Mirad1000 (talk) 23:24, 11 February 2023 (UTC)

title: Talk:Piezoelectricity


text:
Sugar beet

A sugar beet is a plant whose root contains a high concentration of sucrose and which is grown commercially for sugar production. In plant breeding, it is known as the Altissima cultivar group of the common beet (Beta vulgaris). Together with other beet cultivars, such as beetroot and chard, it belongs to the subspecies Beta vulgaris subsp. vulgaris but classified as ''var. saccharifera ''. Its closest wild relative is the sea beet (Beta vulgaris subsp. maritima).

Sugar beets are grown in climates that are too cold for sugarcane. In 2020, Russia, the United States, Germany, France and Turkey were the world's five largest sugar beet producers. In 2010–2011, Europe, and North America except Arctic territories failed to supply the overall domestic demand for sugar and were all net importers of sugar. The US harvested 1,004,600 acre of sugar beets in 2008. In 2009, sugar beets accounted for 20% of the world's sugar production and nearly 30% by 2013. Sugarcane accounts for most of the rest of sugar produced globally. In February 2015, a USDA factsheet reported that sugar beets generally account for about 55 percent of domestically produced sugar, and sugar cane for about 45 percent.

Description
The sugar beet has a conical, white, fleshy root (a taproot) with a flat crown. The plant consists of the root and a rosette of leaves. Sugar is formed by photosynthesis in the leaves and is then stored in the root.

The root of the beet contains 75% water, about 20% sugar, and 5% pulp. The exact sugar content can vary between 12% and 21%, depending on the cultivar and growing conditions. Sugar is the primary value of sugar beet as a cash crop. The pulp, insoluble in water and mainly composed of cellulose, hemicellulose, lignin, and pectin, is used in animal feed. The byproducts of the sugar beet crop, such as pulp and molasses, add another 10% to the value of the harvest.

Sugar beets grow exclusively in the temperate zone, in contrast to sugarcane, which grows exclusively in the tropical and subtropical zones. The average weight of a sugar beet ranges between 0.5 and 1 kg. Sugar beet foliage has a rich, brilliant green color and grows to a height of about 35 cm. The leaves are numerous and broad and grow in a tuft from the crown of the beet, which is usually level with or just above the ground surface.

Discovery of beet sugar

The species beet consists of several cultivar groups. The 16th-century French scientist Olivier de Serres discovered a process for preparing sugar syrup from (red) beetroot. He wrote: "The beet-root, when being boiled, yields a juice similar to syrup of sugar, which is beautiful to look at on account of its vermilion colour" (1575). Because crystallized cane sugar was already available and had a better taste, this process did not become popular.

Modern sugar beets date to the mid-18th century Silesia where Frederick the Great, king of Prussia, subsidized experiments to develop processes for sugar extraction. In 1747, Andreas Sigismund Marggraf, professor of physics in the Academy of Science of Berlin, isolated sugar from beetroots and found them at concentrations of 1.3–1.6%. He also demonstrated that the sugar that could be extracted from beets was identical to that produced from cane. He found the best of these vegetable sources for sugar was the white beet. Despite Marggraf's success in isolating sugar from beets, it did not lead to commercial sugar production.

Development of the sugar beet
Marggraf's student and successor Franz Karl Achard began plant breeding sugar beet in Kaulsdorf near Berlin in 1786. Achard started his plant breeding by evaluating 23 varieties of beet for sugar content. In the end he selected a local strain from Halberstadt in modern-day Saxony-Anhalt, Germany. Moritz Baron von Koppy and his son further selected white, conical tubers from this strain. The selection was named weiße schlesische Zuckerrübe, meaning white Silesian sugar beet. In about 1800, this cultivar boasted about 5–6% sucrose by (dry) weight. It would go on to be the progenitor of all modern sugar beets. The plant breeding process has continued since then, leading to a sucrose content of around 18% in modern varieties.

History of the beet sugar industry
Franz Karl Achard opened the world's first beet sugar factory in 1801, at Kunern, Silesia (now Konary, Poland). The idea to produce sugar from beet was soon introduced to France, whence the European sugar beet industry rapidly expanded. By 1840, about 5% of the world's sugar was derived from sugar beets, and by 1880, this number had risen more than tenfold to over 50%. In North America, the first commercial production started in 1879 at a farm in Alvarado, California. The sugar beet was introduced to Chile by German settlers around 1850.

Culture

The sugar beet, like sugarcane, needs a particular soil and a proper climate for its successful cultivation. The most important requirements are that the soil must contain a large supply of nutrients, be rich in humus, and be able to contain a great deal of moisture. A certain amount of alkali is not necessarily detrimental, as sugar beets are not especially susceptible to injury by some alkali. The ground should be fairly level and well-drained, especially where irrigation is practiced.

Generous crops can be grown in both sandy soil and heavy loams, but the ideal soil is a sandy loam, i.e., a mixture of organic matter, clay and sand. A subsoil of gravel, or the presence of hardpan, is not desirable, as cultivation to a depth of from 12 to 15 in is necessary to produce the best results.

Climatic conditions, temperature, sunshine, rainfall and winds have an important bearing upon the success of sugar beet agriculture. A temperature ranging from 15 to 21 °C during the growing months is most favorable. In the absence of adequate irrigation, 460 mm of rainfall are necessary to raise an average crop. High winds are harmful, as they generally crust the land and prevent the young beets from coming through the ground. The best results are obtained along the coast of southern California, where warm, sunny days succeeded by cool, foggy nights seem to meet sugar beet's favored growth conditions. Sunshine of long duration but not of great intensity is the most important factor in the successful cultivation of sugar beets. Near the equator, the shorter days and the greater heat of the sun sharply reduce the sugar content in the beet.

In high elevation regions such as those of Idaho, Colorado and Utah, where the temperature is high during the daytime, but where the nights are cool, the quality of the sugar beet is excellent. In Michigan, the long summer days from the relatively high latitude (the Lower Peninsula, where production is concentrated, lies between the 41st and 46th parallels North) and the influence of the Great Lakes result in satisfactory climatic conditions for sugar beet culture. Sebewaing, Michigan, lies in the Thumb region of Michigan; both the region and state are major sugar beet producers. Sebewaing is home to one of four Michigan Sugar Company factories. The town sponsors an annual Michigan Sugar Festival.

To cultivate beets successfully, the land must be properly prepared. Deep ploughing is the first principle of beet culture. It allows the roots to penetrate the subsoil without much obstruction, thereby preventing the beet from growing out of the ground, besides enabling it to extract considerable nourishment and moisture from the lower soil. If the latter is too hard, the roots will not penetrate it readily and, as a result, the plant will be pushed up and out of the earth during the process of growth. A hard subsoil is impervious to water and prevents proper drainage. It should not be too loose, however, as this allows the water to pass through more freely than is desirable. Ideally, the soil should be deep, fairly fine and easily penetrable by the roots. It should also be capable of retaining moisture and at the same time admit of a free circulation of air and good drainage. Sugar beet crops exhaust the soil rapidly. Crop rotation is recommended and necessary. Normally, beets are grown in the same ground every third year, peas, beans or grain being raised the other two years.

In most temperate climates, beets are planted in the spring and harvested in the autumn. At the northern end of its range, growing seasons as short as 100 days can produce commercially viable sugar beet crops. In warmer climates, such as in California's Imperial Valley, sugar beets are a winter crop, planted in the autumn and harvested in the spring. In recent years, Syngenta has developed the so-called tropical sugar beet. It allows the plant to grow in tropical and subtropical regions. Beets are planted from a small seed; 1 kg of beet seed comprises 100,000 seeds and will plant over 1 ha of ground (1 lb will plant about 1 acre.

Until the latter half of the 20th century, sugar beet production was highly labor-intensive, as weed control was managed by densely planting the crop, which then had to be manually thinned two or three times with a hoe during the growing season. Harvesting also required many workers. Although the roots could be lifted by a plough-like device which could be pulled by a horse team, the rest of the preparation was by hand. One laborer grabbed the beets by their leaves, knocked them together to shake free loose soil, and then laid them in a row, root to one side, greens to the other. A second worker equipped with a beet hook (a short-handled tool between a billhook and a sickle) followed behind, and would lift the beet and swiftly chop the crown and leaves from the root with a single action. Working this way, he would leave a row of beets that could be forked into the back of a cart.

Today, mechanical sowing, herbicide application for weed control, and mechanical harvesting have displaced this reliance on manual farm work. A root beater uses a series of blades to chop the leaf and crown (which is high in nonsugar impurities) from the root. The beet harvester lifts the root, and removes excess soil from the root in a single pass over the field. A modern harvester is typically able to cover six rows at the same time. The beets are dumped into trucks as the harvester rolls down the field, and then delivered to the factory. The conveyor then removes more soil.

If the beets are to be left for later delivery, they are formed into clamps. Straw bales are used to shield the beets from the weather. Provided the clamp is well built with the right amount of ventilation, the beets do not significantly deteriorate. Beets that freeze and then defrost, produce complex carbohydrates that cause severe production problems in the factory. In the UK, loads may be hand examined at the factory gate before being accepted.

In the US, the fall harvest begins with the first hard frost, which arrests photosynthesis and the further growth of the root. Depending on the local climate, it may be carried out over the course of a few weeks or be prolonged throughout the winter months. The harvest and processing of the beet is referred to as "the campaign", reflecting the organization required to deliver the crop at a steady rate to processing factories that run 24 hours a day for the duration of the harvest and processing (for the UK, the campaign lasts about five months). In the Netherlands, this period is known as de bietencampagne, a time to be careful when driving on local roads in the area while the beets are being grown, because the naturally high clay content of the soil tends to cause slippery roads when soil falls from the trailers during transport.

Production statistics
The world harvested 260998614 t of sugar beets in 2022. The world's largest producer was Russia, with a 48907753 t harvest. The average yield of sugar beet crops worldwide was 60.8 tonnes per hectare.

The most productive sugar beet farms in the world, in 2022, were in Chile, with a nationwide average yield of 106.2 tonnes per hectare.

Imperial Valley (California) farmers have achieved yields of about 160 tonnes per hectare and over 26 tonnes sugar per hectare. Imperial Valley farms benefit from high intensities of incident sunlight and intensive use of irrigation and fertilizers.

From sugar beet to white sugar
Most sugar beet are used to create white sugar. This is done in a beet sugar factory, often abbreviated to sugar factory. Nowadays these most of the time also act as a sugar refinery, but historically the beet sugar factory produced raw sugar and the sugar refinery refined raw sugar to create white sugar.

Sugar factory
In the 1960s, beet sugar processing was described as consisting of these steps.

 * Harvesting and storage in a way that preserves the beet while they wait to be processed
 * Washing and scrubbing to remove soil and debris
 * Slicing the beet in small pieces called cossettes or chips
 * Removing the sugar from the beet in an osmosis process, resulting in raw juice and beet pulp.

Nowadays, most sugar factories then refine the raw juice themselves, without moving it to a sugar refinery. The beet pulp is processed on site to become cattle fodder.

Sugar refinery
The next steps to produce white sugar are not specific for producing sugar from sugar beet. They also apply to producing white sugar from sugar cane. As such, they belong to the sugar refining process, not to the beet sugar production process per se.

 * Purification, the raw juice undergoes a chemical process to remove impurities and create thin juice.
 * Evaporation, the thin juice is concentrated by evaporation to make a "thick juice", roughly 60% sucrose by weight.
 * Crystallization, by boiling under reduced pressure the sugar liquor is turned into crystals and remaining liquor.
 * Centrifugation, in a centrifuge the white sugar crystals are separated from the remaining sugar liquor.
 * The remaining liquor is then boiled and centrifuged, producing a lower grade of crystallised sugar (which is redissolved to feed the white sugar pans) and molasses.
 * Further sugar can be recovered from the molasses eg by the Steffen Process.

From molasses
There are two obvious methods to produce alcohol (ethanol) from sugar beet. The first method produces alcohol as a byproduct of manufacturing sugar. It is about fermenting the sugar beet molasses that are left after (the second) centrifugation. This strongly resembles the manufacture of rum from sugar cane molasses. In a number of countries, notably the Czech Republic and Slovakia, this analogy led to making a rum-like distilled spirit called Tuzemak. On the Åland Islands, a similar drink is made under the brand name Kobba Libre.

From sugar beet
The second method to produce alcohol from sugar beet is to ferment the sugar beet themselves. I.e. without attempting to produce sugar. The idea to distill sugar from the beet came up soon after the first beet sugar factory was established. Between 1852 and 1854 Champonnois devised a good system to distill alcohol from sugar beet. Within a few years a large sugar distilling industry was created in France. The current process to produce alcohol by fermenting and distilling sugar beet consists of these steps:

 * Adding Starch milk
 * Liquefaction and Saccharification
 * Fermentation in fermentation vats
 * Distillation
 * Dehydration, this results in Bioethanol
 * Rectification
 * Refining, the result is a highly pure alcohol

Large sugar beet distilleries remain limited to Europe. In 2023 Tereos had 8 beet sugar distilleries, located in France, Czechia and Romania.

In many European countries rectified spirit from sugar beet is used to make Liquor, e.g. vodka, Gin etc..

Sugary syrup
An unrefined sugary syrup can be produced directly from sugar beet. This thick, dark syrup is produced by cooking shredded sugar beet for several hours, then pressing the resulting mash and concentrating the juice produced until it has a consistency similar to that of honey. No other ingredients are used.

In Germany, particularly the Rhineland area, and in the Netherlands, this sugar beet syrup (called Zuckerrüben-Sirup or Zapp in German, or Suikerstroop in Dutch) is used as a spread for sandwiches, as well as for sweetening sauces, cakes and desserts. Dutch people generally top their pancakes with stroop.

Suikerstroop made according to the Dutch tradition is a Traditional Speciality Guaranteed under EU and UK law. Commercially, if the syrup has a dextrose equivalency (DE) above 30, the product has to be hydrolyzed and converted to a high-fructose syrup, much like high-fructose corn syrup, or isoglucose syrup in the EU.

Uridine
Uridine can be isolated from sugar beet.

Alternative fuel
BP and Associated British Foods plan to use agricultural surpluses of sugar beet to produce biobutanol in East Anglia in the United Kingdom.

The feedstock-to-yield ratio for sugarbeet is 56:9. Therefore, it takes 6.22 kg of sugar beet to produce 1 kg of ethanol (approximately 1.27 L at room temperature). In 2006 it was found that producing ethanol from sugar beet or cane became profitable when market prices for ethanol were close to $4 per gallon.

Cattle feed
In New Zealand, sugar beet is widely grown and harvested as feed for dairy cattle. It is regarded as superior to fodder beet, because it has a lower water content (resulting in better storage properties). Both the beet bulb and the leaves (with 25% protein) are fed to cattle. Although long considered toxic to cattle, harvested beet bulbs can be fed to cattle if they are appropriately transitioned to their new diet. Dairy cattle in New Zealand can thrive on just pasture and beets, without silage or other supplementary feed. The crop is also now grown in some parts of Australia as cattle feed.

Monosodium glutamate
Molasses can serve to produce monosodium glutamate (MSG).

Agriculture

Sugar beets are an important part of a crop rotation cycle.

Sugar beet plants are susceptible to Rhizomania ("root madness"), which turns the bulbous tap root into many small roots, making the crop economically unprocessable. Strict controls are enforced in European countries to prevent the spread, but it is already present in some areas. It is also susceptible to both the beet leaf curl virus, which causes crinkling and stunting of the leaves and beet yellows virus.

Continual research looks for varieties with resistance, as well as increased sugar yield. Sugar beet breeding research in the United States is most prominently conducted at various USDA Agricultural Research Stations, including one in Fort Collins, Colorado, headed by Linda Hanson and Leonard Panella; one in Fargo, North Dakota, headed by John Wieland; and one at Michigan State University in East Lansing, Michigan, headed by Rachel Naegele.

Other economically important members of the subfamily Chenopodioideae:
 * Beetroot
 * Chard
 * Mangelwurzel or fodder beet

Genetic modification
In the United States, genetically modified sugar beets, engineered for resistance to glyphosate, a herbicide marketed as Roundup, were developed by Monsanto as a genetically modified crop. In 2005, the US Department of Agriculture-Animal and Plant Health Inspection Service (USDA-APHIS) deregulated glyphosate-resistant sugar beets after it conducted an environmental assessment and determined glyphosate-resistant sugar beets were highly unlikely to become a plant pest. Sugar from glyphosate-resistant sugar beets has been approved for human and animal consumption in multiple countries, but commercial production of biotech beets has been approved only in the United States and Canada. Studies have concluded the sugar from glyphosate-resistant sugar beets has the same nutritional value as sugar from conventional sugar beets. After deregulation in 2005, glyphosate-resistant sugar beets were extensively adopted in the United States. About 95% of sugar beet acres in the US were planted with glyphosate-resistant seed in 2011.

Weeds may be chemically controlled using glyphosate without harming the crop. After planting sugar beet seed, weeds emerge in fields and growers apply glyphosate to control them. Glyphosate is commonly used in field crops because it controls a broad spectrum of weed species and has a low toxicity. A study from the UK suggests yields of genetically modified beet were greater than conventional, while another from the North Dakota State University extension service found lower yields. The introduction of glyphosate-resistant sugar beets may contribute to the growing number of glyphosate-resistant weeds, so Monsanto has developed a program to encourage growers to use different herbicide modes of action to control their weeds.

In 2008, the Center for Food Safety, the Sierra Club, the Organic Seed Alliance and High Mowing Seeds filed a lawsuit against USDA-APHIS regarding their decision to deregulate glyphosate-resistant sugar beets in 2005. The organizations expressed concerns regarding glyphosate-resistant sugar beets' ability to potentially cross-pollinate with conventional sugar beets. U.S. District Judge Jeffrey S. White, US District Court for the Northern District of California, revoked the deregulation of glyphosate-resistant sugar beets and declared it unlawful for growers to plant glyphosate-resistant sugar beets in the spring of 2011. Believing a sugar shortage would occur USDA-APHIS developed three options in the environmental assessment to address the concerns of environmentalists. In 2011, a federal appeals court for the Northern district of California in San Francisco overturned the ruling. In July 2012, after completing an environmental impact assessment and a plant pest risk assessment the USDA deregulated Monsanto's Roundup Ready sugar beets.

Genome and genetics
The sugar beet genome shares a triplication event somewhere super-Caryophyllales and at or sub-Eudicots. It has been sequenced and two reference genome sequences have already been generated. The genome size of the sugar beet is approximately 731 (714–758) Megabases, and sugar beet DNA is packaged in 18 metacentric chromosomes (2n=2x=18). All sugar beet centromeres are made up of a single satellite DNA family and centromere-specific LTR retrotransposons. More than 60% of sugar beet's DNA is repetitive, mostly distributed in a dispersed way along the chromosomes.

Crop wild beet populations (B. vulgaris ssp. maritima) have been sequenced as well, allowing for identification of the resistance gene Rz2 in the wild progenitor. Rz2 confers resistance to rhizomania, commonly known as the sugar beet root madness disease.

Breeding
Sugar beets have been bred for increased sugar content, from 8% to 18% in the 200 years, resistance to viral and fungal diseases, increased taproot size, monogermy, and less bolting. Breeding has been eased by discovery of a cytoplasmic male sterility line – this has especially been useful in yield breeding.

title: Sugar beet