Talk:Unusual types of gramophone records

Unrec01 ubt


Thanks for the nice illustration! -- Infrogmation 00:13, 24 Aug 2004 (UTC)

Triple Inchophone
Now that the article has been deleted, shouldn't it be incorporated here? Pellucidity 07:25, 7 July 2007 (UTC)

Shaped picture discs
Should also include mention of these. --Daniel C. Boyer 18:16, 27 Sep 2004 (UTC)

I have a scan of the shape picture version of Poland by Tangerine Dream if that would add anything here. --Gadget850 ( Ed) 17:14, 1 August 2006 (UTC)

Actually, it is Warsaw in the Sun, a remix of Poland. The record is in the shape of Poland, the bottom center images are of Lech Wałęsa and Pope John Paul II. --Gadget850 ( Ed) 02:53, 22 December 2006 (UTC)

I just edited the image as it was not properley oriented. --Gadget850 ( Ed) 16:10, 22 December 2006 (UTC)

Multi-grooved records
Could the same trick be tried on CD? Has anyone ever tried a CD with two or more intelaced spiral tracks of pits and lands?

No i don't think so, because with a record the needle follows the track around the record, ie. the record determines where to needle moves. For a cd, the lazer does not follow the tracks, it just moves in the standard way, independent of the way the information is written on the cd as there is no physical connection. --LeakeyJee 12:14, 28 April 2006 (UTC)


 * That's not actually true. The laser follows the track as impressed on the disc using a couple of side beams designed to detect when the track is moving off the centre line.  Recording a disc with interlaced tracks would be entirely feasible.  There may be a problem when selecting individual tracks if the laser picked up the alternate track before finding the correct one.

Locked grooves
A locked track on the edge of a CD (the track spirals outward from the centre) would not achieve the same effect because the turning speed of CDs is much higher than that of an LP. But could the same effect be emulated by digital technology?
 * CDs can skip in much the same way as records, especially when dropped down the side of a car seat! Spenny 15:27, 19 March 2006 (UTC)
 * I don't think you could rely on every CD player to skip in the same way - some read ahead, some might give up. The CD format doesn't accomodate for any kind of loop function. In other words, not really. Chris 22:28, 24 December 2006 (UTC)

How about a mention of Pierre Schaeffer as an earlier use of locked-groove records than The Beatles? He was using these as loops on plastic discs (before tape was available) to produce Musique Concreté works in the late-40s.

"Bones Records"
A very interesting phenomenon worth considering here are so-called "bones records" (roentgenizdat). In the mid 50's Russia was heavily censoring any Western influences, including music. In order to gain aceess to the music, a copies of records were cut on used, discarded x-ray film, which was plentiful and not likely to be suspected. The quality was poor and degraded quickly. They traveled through musical circles not unlike peer-to-peer file sharing. Musical material ranged from swing and bebop to early rock/R &B. Reportedly the most popular title was "Rock Around the Clock."

Kraftwerk Neon
According to rumours, the single's production ended prematurely when the plastic was discovered to be toxic, adding to the records rarity. Whilst this comment is noted as a rumour, I don't think it is substatiated. The single (c/w Trans Europe Express and The Model) is made of a form that is luminous because of sun light. People get confused over the fact that up until the 1970s, many watches had luminous dials made with radiactive material (which worked throughout the day and night and did not need to be recharged). As proud owner of the 12", I can confirm it did/does not glow without being charged in daylight. Mind you it might explain the 15 foot long spider in my attic! I suspect it was withdrawn simply because it was a special edition, or simply did not sell. Spenny 15:51, 19 March 2006 (UTC)

Froot Loops record
I once had square record that came with a box of Froot Loops. Wish I still had it. PrometheusX303 01:52, 4 June 2006 (UTC)

You mean the cardboard record you cut out of the back of the box? I seem to recall one by the Archies. --Gadget850 ( Ed) 17:12, 1 August 2006 (UTC)

Yup. I can't remember what was on it, though. Prome theus  -X303-  17:15, 21 December 2006 (UTC)

Inside-to-outside recording
Mid-20th-century broadcasting-style record cutters could record in either direction. I believe starting from the inside and then spiraling out mitigated the problem of the sudden increase in drag when the cutter is lowered onto the platter. I have some 1952 recordings made at a radio station from the outside-in and the beginning of each has a very noticeable speed variation. If the cutter was lowered at the inside, there would be less torque produced and hence the speed would not be affected as much. (My particular recordings were intended for use on a commercial-grade phonograph, hence they were recorded in the conventional direction.) Does anybody else agree with this view?

Jmatxx 23:19, 11 November 2006 (UTC)

Flexis & cardboard records
Given that these two articles probably aren't going to get an awful lot bigger, I think they should be merged here. Thoughts? Tzaquiel 17:07, 21 December 2006 (UTC)


 * Merge. They fit the subject matter of this article.  Prome  theus  -X303-  17:15, 21 December 2006 (UTC)


 * Nope. The term flexidisc is used frequently, and it's not self-explanatory in the same way that the other odd varieties on this page are. Chris 21:16, 24 December 2006 (UTC)


 * Nope. No way! flexi-disc is a specific format, historically widely used. Why not have it's own page? If it was a type of Pokemon it would have it's own page for sure, so why not a type of record?! :) And "unusual" isn't a very 'encyclopedic' catagory anyway really, I think it's worthwhile to make specific pages for the more notable unusual formats. :-S 85.8.189.11 13:55, 28 June 2007 (UTC)

Polish postcards
This might be interesting: --Gadget850 ( Ed) 02:29, 9 January 2007 (UTC)

Large holes on 45s
I initially requested a citation regarding 45s having larger holes to accomodate jukeboxes. I have a citation to the contrary and will simply change the text.Squad51 21:33, 25 January 2007 (UTC)


 * There's no denying that the application to jukeboxes exists, whether it was the reason the larger hole size was invented or not. A quick Google search produces a number of references for this use.  And I've seen at least one jukebox of this kind in my life.  So AISI, it wasn't right to remove the mention of it completely. -- Smjg 14:18, 17 October 2007 (UTC)

I can confirm that some jukebox versions of 45's were manufactured but most had the push out centers allowing them to be used on both platforms or were "dinked" (large hole punched with a "dinking machine"). Plastic inserts were sold to the public that allowed jukebox records to be played on regular equipment (as many jukebox records were recycled after use and sold at a discount).

REFS: -

"Heartbreak Hotel / Hound Dog Jukebox 45 RPM 7" Elvis Presley Vinyl Single Elvis Presley Heartbreak Hotel / Hound Dog 45 RPM Vinyl JUKEBOX single to promote the release of the The King Of Rock 'n' Roll box set. Limited availability. From RCA USA 1992 07863-62449-7 (Factory new - never played) Single included with the juke box strip and large hole (We will supply insert to play on standard player.)"

http://shop.elvis.com.au/category111_1.htm

"In addition, the RCA engineers designed the new 45 disc featuring the large center 'hole' to prevent the stress and damage common to the shellac 78 disc small center 'hole' by a combination of the records weight and mechanical auto changers. The new 45 RPM disc records would not suffer either surface or 'hole' damage,"

http://www.downstairsrecords.com/about/rpm.html —Preceding unsigned comment added by Aimulti (talk • contribs) 08:15, 7 April 2008 (UTC)

Aimulti (talk) 08:16, 7 April 2008 (UTC)

Binaural recordings
There was a short section here I removed earlier, containing the text italicized below:
 * An early binaural format — Before the development of the single-groove stereo system circa 1957, at least one company, Cook Laboratories, released a number of "binaural" recordings. Each side of one of these recordings consisted of two long, continuous tracks — one containing the left-ear signal, one containing the right-ear signal. It was intended that the buyer purchase an adapter from Cook Laboratories that allowed two cartridges to be mounted together, with the proper spacing, on a single tone arm. Only a very small number of recordings were ever released in this format. It is not known how many purchasers went to the effort and expense needed to play them binaurally. Binaural recordings resurfaced in the late 1970s, Pink Floyd used several binaural sound effects on The Final Cut, and the German group Can released several LPs recorded using the technique. However, these simply used the standard stereo system to encode the sound.

This article is about unusual types of gramophone records, the discs with spiral grooves. This section discusses an unusual kind of record groove layouts -- two parallel spirals, one for each channel. These are unusual because the industry settled on a single-groove system when it began to mass-produce binaural records.

There is no need to say that binaural recordings resurfaced. They of course rapidly became the standard format which ushered the record industry into maturity. This section is talking about an unusual kind of binaural (stereo) record.

I think the text I removed is trying to refer to QSound, which is a kind of binaural sound effect. It really isn't relevant at all in this article, as the recordings that used it and other similar systems have all been standard stereo records.

Let's please try to keep this article on its topic. &mdash;ptk✰fgs 11:48, 28 May 2007 (UTC)


 * I object to the continued removal of the information. Each time I have justified its inclusion and each time you have arbitrarily deleted. Your justification in this case is wrong: QSound is not binaural - follow the link to binaural and you will see that there is more to it. Your interpretation is that it is unusual physical attributes, it is not my interpretation - we would delete unusual speeds on that basis.


 * QSound absolutely is binaural. Follow the link and read the article. It presents "3D sound" using two channels. The meaning of the word "binaural" is "two-channel audio".


 * On the more general point, it is quite appropriate to give a context to the topics discussed. You didn't like that under grooving, so I created a different section which noted some other relevant unusual types: short notes referring to the explicit articles. To me, the point of a Wiki is to be able to create explorable information. If you are too strict on topic then you lose that. Is colouring vinyl unusual - arguably not, they were very common in the 1970s, and there was nothing technical about them, but it is of interest. Binaural and quadraphonic are interesting variations - a lot less common than picture discs and coloured vinyl.


 * Binaural (stereo) records are as common as dirt. We should discuss quadrophonic recordings here, but then again I've never had an objection to that.


 * So I think guiding the readers onto other topics of interest is appropriate. Backwards recording - more interesting than other speeds; quadraphonic recording, of interest for people who find that Dolby 5.1 of today came out of earlier failed experiments in the 1970s. Binaural is of interest if you didn't know of this rare recording format (and if you heard one of Can's LPs you would find it has an interesting sonic quality that is worth seeking out). Spenny 20:23, 28 May 2007 (UTC)


 * Binaural is a synonym for "stereo". That's all. &mdash;ptk✰fgs 21:20, 28 May 2007 (UTC)


 * I am sorry, but you misunderstand the difference between binaural and stereo. Binaural is more than just a two channel stero system, it is a use of the acoustic properties of the head to create a realistic sound field, it is not synonymous. Arguably the error is in describing the original system as binaural in the context of the modern understanding of the word. Here is the quote from that very article:


 * Binaural recording is a method of recording audio which uses a special microphone arrangement. Dummy head recording refers to a specific method of capturing the audio, generally using a bust.


 * The term "binaural" has often been confused as a synonym for the word "stereo", and this is partially due to a large amount of misuse in the mid-1950s by the recording industry, as a marketing buzzword. Conventional stereo recordings do not factor in natural crossfeed or sonic shaping of the head and ear, since these things happen naturally as a person listens, generating their own ITDs (interaural time differences) and ILDs (interaural level differences).


 * Binaural is understood to mean this enhancement. Stereo recording is simply two channels - listen to early Beatles recordings and you will find that there are several mono tracks assigned left right and centre. Binaural is a process of capturing the actual sounds from within the ear to allow the subtleties of placement to be captured. QSound is not precisely the same thing (it was a 1990s innovation) and that relies on the artificial generation of some of the signals, but it is related. If you want a disambiguation to make the difference clear then we can add that, to emphasise that the meaning of binaural in the context of 1970s and 1980s records is the use of a head stereo recording technique. I feel it is important because it is fundamentally about the determination to go beyond the apparent limitations of a two channel system which in the modern world has been abandoned and technology allows recordings to be produced in multiple discrete channels.


 * Seriously, I tried to address your valid criticism of the confusion of the physical traits - however, I do believe it is important to be aware of context. As is clear, you have misunderstood the issue, which is entirely understandable as the binaural topic makes clear, so I think that the linking in to the topic is appropriate. So I insist that you stop reverting my edits which you also acknowledge have other items of relevance in them. Spenny 09:09, 29 May 2007 (UTC)

Request for Comment: Binaural Recordings
This is a dispute about whether binaural recordings are appropriate to this article 09:41, 29 May 2007 (UTC)


 * Statements by editors previously involved in dispute

Binaural recordings were introduced into the article some time ago due to the use of two grooves to represent the two channels of recording. Again some time ago, by way of clarification, an edit was added to note that binaural recordings also existed. Ptkfgs recently deleted the comment as he felt that it was an irrelevance, however, I reinstated the edit with a short explanation as to why. This clearly did not satisfy the editor and he reverted the edit. I therefore considered the specific issue he raised and determined that there was some merit in his concerns and therefore created a section which attempted to keep what I felt was an important clarification and concept in the article and introduce summary links into other related information, yet resolve the concerns on the ambiguity. I provided the justification in the talk (above). For the understandable reason of the ambiguity of the term binaural (which is addressed in that article) the edits were again disputed and entirely reverted, even though some other information introduced was acknowledged to be relevant. Rather than continue the tennis match, I think it would be appropriate for a neutral view to be given on the appropriateness of the links of other information. Spenny 09:41, 29 May 2007 (UTC)


 * Comments

The insertion of the irrelevant content appears to derive from a misunderstanding of the meaning of the word "binaural" when discussing the manufacture of gramophone records. Binaural, in general audio discussion, is merely a synonym for "stereo" or "two channel audio". This is why the unusual two-groove/two-pickup system is mentioned here. The new section "Unusual recording techniques" discusses a second esoteric meaning of "binaural", referring to binaural sound effects that attempt to reproduce three-dimensional sound spatialization using a standard stereo signal.

The Oxford English Dictionary confirms this more general application of the term:
 * ''1. Of or pertaining to one's two ears; used with both ears, as the binaural stethoscope.
 * ''1861 [see STETHOSCOPE n.]. 1878 Engineering XXIV. 151/3 Mr. S. P. Thompson..read his paper ‘On Binaural Audition’. 1881 LE CONTE Light 265 A kind of binaural audition, by means of which we judge imperfectly of direction of sound. 1881 Nature XXV. 208.
 * ''2. Applied to a system of sound reproduction that uses two separated microphones and two transmission channels to achieve a stereophonic effect; esp. one in which the sound is delivered to each ear separately by earphones.
 * ''1933 Electronics July 196/2 Ready-made equipment for an experiment with binaural transmission. 1952 N.Y. Times 26 Oct. II. 11/6 In binaural transmission, the sound is broadcast on both the standard radio wave length and on FM. In the home two receivers are necessary to achieve the effect of ‘three dimensional’ sound. 1958 N.Z. Listener 10 Oct. 21/3 In a binaural recording of an orchestral performance, two microphones would be placed some distance apart among the players and the output from each microphone recorded separately. Both sound tracks would then go onto a single tape or onto a single record.

There are millions of unusual recording techniques, and discussing them here is not on the topic of the article. The binaural sound effects used by Can and Pink Floyd do not affect the physical attributes of the record; the rest of this article is about physically unusual records. If we include discussion of unusual sound effects inside the signal of a standard LP, we are going to be left with a directionless mess of an article. This is not "unusual music recordings"; it is about unusual variations to the discs themselves.

Surely this material is encyclopedic if it can be sourced, but this is not the place for it. This article is about unusual types of gramophone records, not unusual types of sound effects. &mdash;ptk✰fgs 20:05, 29 May 2007 (UTC)

A couple of things for you to think about: on your rationale, how would you fix the binaural recording and Stereophonic soundpages? Secondly, my point was exactly to create direction, rather than leaving a sterile (and arguably unencyclopaedic) listing page, here is a small link to topics, not of etymological but of encyclopaedic knowledge.


 * I don't think there's anything to fix. Binaural is, as it should be, a stub page defining the word, and pointing the reader to articles about different senses of the word.

To go back to the comment on "does it fit?": if I go back through my beloved but unused records in the attic, showing them to a young person who did not know about such things, which ones would I pull out? I'd pull out my Kraftwerk 12" Neon Lights (which still glows now), I'd pull out my coloured vinyl, but I would pull out my Renaissance with its Aphex Aural Exciter, my ELO (sticking it on the turntable and playing it), my Hi-Fi Answers Test Record. These are things of interest which tell the story of the heyday of the technology - they have a "wow! what about this!" to me. Thelma Houston's direct to disc recording also tells a story of a direction disc technology took: just a record, but the back-story of the technology (and audiophile fixation technology over content) makes it unusual. Beach Boys Holland - a "double album" where the second record was a 7" fairy tale story. I hope it explains my POV as to why it is an appropriate direction in which to take the article. Where to put this information - the main topics are busy, and should be focused on the mainstream - here we have a nice little article from which to leap off into wider research - it seems right to me.


 * We cannot let this turn into an article about "unusual music recordings." That topic is far too broad. Every musician tries to make a unique recording. Selecting the two "binaural recording" examples is an arbitrary and unrepresentative approach, and drags the article away from its focus.
 * This article is about the physical records. A discussion of unusual recording techniques belongs in its own article, not tacked on here where it's not relevant.

Finally, I note the citation tag added. I think that is an inappropriate tactic to try and assert your POV. The reference material is in the actual articles, which are of sound quality. This is simply a summary paragraph referencing other main articles, the citation is there by dint of the reference so there is no need to litter text with further references. Let this play out please. Spenny 09:11, 30 May 2007 (UTC)


 * The claims are unreferenced. If we must include off-topic material in this article, then it must comply with Wikipedia policy. A reference to another Wikipedia article is not appropriate. &mdash;ptk✰fgs 15:37, 30 May 2007 (UTC)


 * I'll reserve my comments to avoid inflaming you further. I note that you are not acting in good faith to resolve this amicably. Spenny 16:15, 30 May 2007 (UTC)


 * The articles for the recordings named in the disputed section don't mention anything about having been recorded using binaural dummy heads. We definitely need a source for those claims somewhere.
 * One solution which might make sense is to clarify that the two-groove binaural records were standard stereo recordings, noting that this is different from binaural dummy recording. I'll try this out in the unusual grooving section and add a short blurb about quadrophonic records. &mdash;ptk✰fgs 22:20, 30 May 2007 (UTC)


 * Thanks, that is an excellent solution. I am pleased that you have come up with a good resolution which shows that you understand my original concern about the ambiguity of the article. Spenny 08:27, 31 May 2007 (UTC)

Fair use rationale for Image:Warsaw in the Sun shape (TD).jpg
Image:Warsaw in the Sun shape (TD).jpg is being used on this article. I notice the image page specifies that the image is being used under fair use but there is no explanation or rationale as to why its use in this Wikipedia article constitutes fair use. In addition to the boilerplate fair use template, you must also write out on the image description page a specific explanation or rationale for why using this image in each article is consistent with fair use.

Please go to the image description page and edit it to include a fair use rationale. Using one of the templates at Fair use rationale guideline is an easy way to insure that your image is in compliance with Wikipedia policy, but remember that you must complete the template. Do not simply insert a blank template on an image page.

If there is other fair use media, consider checking that you have specified the fair use rationale on the other images used on this page. Note that any fair use images lacking such an explanation can be deleted one week after being tagged, as described on criteria for speedy deletion. If you have any questions please ask them at the Media copyright questions page. Thank you.

BetacommandBot (talk) 03:19, 12 February 2008 (UTC)

Typo?: 1/3 bpm and are replayed at 33 1/3 rpm
Locked grooves: "would play seamlessly to a locked groove at the end of a side. There are also many techno records featuring loops as locked grooves, which, when recorded at 133 1/3 bpm and are replayed at 33 1/3 rpm, will continuously repeat the beats and musical phrases, which can then be utilised creatively by a DJ."

Is this a typo? Should it be 33 1/3 at both places?

Is it necessary to write that it is recorded in one speed and that it should be played back in that same speed?--Bjornwireen (talk) 08:03, 15 June 2008 (UTC)

some stuff has been overlooked
Arcade fire's neon bible: on the locked groove at the end of side four there is some electronic bubbling noises

Lou reed's metal machine music: the noise on side D runs into the locked groove

Lee ranaldo's (I don't remember the name) is entirely based on locked grooves

Fucked up's year of the dog has double grooves but that's probably not relevant. 79.72.249.28 (talk) 14:18, 1 October 2009 (UTC)

There is nothing about the 1970's and 80's 33.33 rpm Golden Hour LP's which played for at least 60 minutes.

There is at least one 33.33 rpm 1970's LP of Beethoven's 9th Symphony which plays for almost 65 minutes.

There is no mention of several 78 rpm jazz records which were made out of glass in the 1940's.

Reference to Godspeed You! Black Emperor
The phrase "The title's "infinity" refers to this phrase." in the article is misleading. F#A#(infinity) refers to a guitar tuning used on the album: F# A# F# A# F# A# etc. I can't find the source of this, so, I won't modify the contents of the article, but if someone could look into this, I'd appreciate it. —Preceding unsigned comment added by AnarchistWeasel (talk • contribs) 13:57, 5 November 2009 (UTC)

Curved Air's Airconditioning
Could someone familiar with this article please check the caption of the Curved Air's Airconditioning image? The original image had a caption in the image itself which I transcribed as accurately as possible. However, someone might wish to double check the spelling of Mark's last name and the quantity pressed. JBarta (talk) 14:19, 4 February 2010 (UTC)

McDonalds square record
I remember this square record from way back in the day, I think it was a promotional item, and it had a jingle on it. Maybe it could be mentioned here. -- blm07 06:21, 26 January 2011 (UTC)

Excessive examples
There are generally more examples of certain techniques than necessary. The Unusual grooving section should be trimmed to include illustrative or notable examples only. --Kvng (talk) 16:08, 8 February 2011 (UTC)

Slap-A-Ham 1 & 2 inch "records"
These were not really records. The bands "on" these "records" did not record music for them, and the actual records were plastic arts & craft items label owner Chris Dodge found in an arts & craft store, he made tiny sleeves for them with band names on them, and were meant to be a joke, they should probably be removed from the article, although it is amusing something so obsucre made it into this article. garyleejr@outlook.com — Preceding unsigned comment added by 74.78.154.65 (talk) 07:43, 20 December 2013 (UTC)

4 inch
There are also 4" records, both flexi and hard vinyl. Discogs shows 159 of these types of records if you do an advanced search and click on format  — Preceding unsigned comment added by 74.78.154.65 (talk) 07:51, 20 December 2013 (UTC)

Multi-speed record
I think mention should be made of Nash the Slash's "Decomposing", which was advertised as "playable at any speed" (although actually only 33, 45 and 78--it sounded pretty dire at 16) — Preceding unsigned comment added by 206.177.43.88 (talk) 23:42, 4 February 2014 (UTC)

External links modified
Hello fellow Wikipedians,

I have just added archive links to 1 one external link on Unusual types of gramophone records. Please take a moment to review my edit. If necessary, add after the link to keep me from modifying it. Alternatively, you can add to keep me off the page altogether. I made the following changes:
 * Added archive https://web.archive.org/20070706044440/http://exd.sohc.org:80/RE10.php?letter=n to http://exd.sohc.org/RE10.php?letter=n

When you have finished reviewing my changes, please set the checked parameter below to true to let others know.

Cheers.—cyberbot II  Talk to my owner :Online 05:33, 8 January 2016 (UTC)

Trying to find an image of the original sticker on Metallica's Black Album
Which was 63 minutes. If memory serves, it shipped with a sticker that said "We could have put this on a single LP, but it would have sounded like sh*t". Which I'm guessing was directed at Def Leppard, whose "Hysteria" was also 63 minutes and shipped on a single LP. The internet is failing me. - Immigrant laborer (talk) 20:21, 14 September 2017 (UTC)

Trimicron info source
Source of the information is unclear; appears to be taken from here, but it's not clear if that is the original source. There's this edit at fr.wikipedia in 2009, and someone has a middling-quality translation here at Discogs, but I haven't checked whether the other discogs source is an improved (later) translation or whether the other discogs source came first and was translated two ways(?)

(IIRC I had a Discogs account once, but I don't have the time right now to find it and log in to see when that edit was made, assuming that's possible).

If the fr.wikipedia is the original source, that's probably fine. If not, it's probably plagiarism.

Ubcule (talk) 23:21, 26 July 2018 (UTC)


 * I did a bit of editing on this section, as it was a very crude translation from the French text and could be improved a bit. In terms of original sources, I know the youtuber Techmoan covered the format in a video this year, at least. https://www.youtube.com/watch?v=5fG1crhGqI0 --Agamemnon2 (talk) 07:40, 24 December 2018 (UTC)
 * It would probably be a good idea to be certain that we are following WP:RS, though. Techmoan has been used on a handful of articles at Wikipedia, but it would probably be a good idea to run it by WP:RSN before we base the entire subsection on that source alone. And of course if there are no reliable sources then it should be removed until such sources can be located and properly cited. -Thibbs (talk) 20:59, 24 December 2018 (UTC)

3 inch record
The 8-ban record is three inches. It runs at 33 1/3 rpm like LPs. Reference: http://web.archive.org/web/20040612161316/http://8-ban.com/ — Preceding unsigned comment added by 210.185.105.160 (talk) 08:38, 9 July 2020 (UTC)

Pocket Discs
The Pocket Discs were 4 inch 33 RPM flexi discs released in the late 1960s. They were small and could fit in a pocket.