RetroTech: Extended Play - The 2 hour LP & 2.5 hour CD

A look at two different approaches at squeezing more music onto one disc. Featuring Trimicron the longest 33 1/3rd Stereo Vinyl Records that held two hours of music and a CD that contained two and a half hours of audio.

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I should really learn when to keep my thoughts to myself as my brief passing comment about the phrase "Without Forgetting to Switch on” has become the most commented upon thing.
Here's why I mentioned it - it just sounded weird to me. I was taught English a long time ago from some very old ladies who had a very particular old fashioned way of speaking. Whilst probably 99% of people wouldn’t even notice anything unusual - to me it’s a strange way to phrase a simple message . A much cleaner and more elegant way to say the same thing would be "Remember to switch on” - - it just flows better. Its like saying 'Don’t forget to remember to feed the dog'. It’s just a really messy and complicated way to get a simple message across. Almost everyone on the planet would be happy with the way the chap said it - but it grated against the way I was taught English - to write and speak in the most efficient way possible. I really shouldn’t have said anything about it - so my apologies for causing all this consternation. In future I'll have to remember to not forget to not bite my tongue.

[drdemento]

This was also used for awhile for audio books. A special cassette player with a left and right switch allows the four tracks to be used for four mono channels.

[TracyMarkGorgas]

Nice touch with the extra facts during the credits/Patreon call-outs, I like it. Fills out the video nicely.

[HomieJeans]

Wow that CD was a really dumb idea lol

[RichardCraig]

I remember having a Compton's Interactive Encyclopedia back in the dawn of CD-ROM that used the redbook audio in the same way, with the left channel being recordings of word pronunciations and the right channel being music, sounds, etc.

[alptigin]

Yeah, well if Snopes calls something "unconfirmed", it means "100% true with no ambiguity whatsoever, we just don't like it."

[tomcarlson]

A few thoughts:
The method used in the LP CD was nothing new. Back in the early days of consumer stereophonic RTR tape (late 50's-early 60's) some makers encouraged this practice for mono recordings. I have a VM RTR with manual stashed away that was able to do both 2 track and 4 track stereo. It's mode switch also allowed recording mono to whichever of the 4 tracks you wanted without disturbing the others. It was touted as a way to economize on tape when recording monophonic material.

That Trigram (hope I remembered the spelling) logo appears to be based on a phosphor dot triad/electron gun orientation from a delta-gun color CRT...Which was the predominant color CRT tech here in the United States until the mid 70's when inline gun color CRTs began to take over. Up to that time, that pattern and variations thereof were very common in tech marketing and literature especially if TV was involved.

The grooves look straight because of the lower recording volume which also contributes to the accentuated crackle. That technique was not new either. A well-known example is K-tel's popular music compilation albums going back to the 60's (other earlier examples existed) which often fit 10+ songs on a side. If you have a K-tel compilation album and another album by one of the same artists with a song in common between the two, and you compare the song in common when you play the K-tel record you can hear the reduction in recording volume, reduction in dynamic range, and the reduction of SNR (manifested in increased crackle and background noise). Disco Singles/Club Singles (relatively short duration song taking up an entire side of a 12" LP usually at 33RPM, but sometimes at 45RPM) tended to do the opposite increasing groove spacing and recording volume beyond standard/average settings to improve dynamic range and increase SNR via boosting the signal. The examples Disco Single I have do seem to accomplish that goal when compared to the same songs on their consumer album releases. The reduction in crackle must have been well-liked by club DJs back in the day.
Modern mastering machines try to strike a compromise by monitoring the audio a groove or twos worth of time in advance of the cutting styli, predicting the audio modulated groove width and actively adjusting the groove spacing throughout the recording process to minimize the islands between grooves.

[Nezuji]

Near the beginning, when you introduced the two formats and then started with the CD, I thought, "What? Getting around CD Redbook is going to take way more ingenuity and be more interesting than the record, which is just going to be more tightly-packed grooves. You should start with the records!" Of course, I should've had more faith in your presentation abilities; the CD did turn out to be quite a simple "trick" (can we even call it that?), while the record involved overcoming a lot more technical challenges than I had imagined. Great job as usual!

[project]

Absolutly fantastic video!! My congratulations for producing good hifi videos! Please do keep making these! And God bless

[desmof]

I heard a bit of a radio programme recently about 12 inch singles and it talked about how the extra space allowed more dynamic range. “The 12 Inch Single” on radio iPlayer.

[timothystockman]

CDs with mono material are actually more of a subject than most people think. The correct way to make a CD is to use only one channel of an 18 bit or more ADC. That digital data is duplicated bit-for-bit to the other channel. INDEPENDENT dither is applied to each channel before truncating to 16 bits. The Beatles in Mono box set is an example of proper technique. I would estimate that this is done on less than 10% of the CDs which are mastered.


Usually the mono master tape is played back on a stereo machine, through a stereo audio path to a stereo DAC. The resulting stereo data is used to master the CD. Try reading a CD into an audio editor and taking the difference of its channels. Quite often one can hear every flaw in the tape, creases, dirt, oxide shed, azimuth errors, etc., magnified in the difference signal.


When reading mono CDs to my hard drive, I make the best mono FLAC file I can, which would be a 24 bit mono file to retain the 17th bit that independent dither provides on correctly mastered CDs. On other CDs, I either pick the best sounding channel and make a 16 bit mono FLAC file, or I sum the channels to a 24 bit FLAC file, depending on what sounds best.

[jarryjayo]

there is a documentary about the history of K-tel music and if you look hard on youtube you can find it. and they would make these record albums with 20 greatest hits all on one album. the problem was after two maybe three playing's the album would not work ever again.

This dvd format would of been fine for classical music, opera, as most of it is record in mono anyway, well older music is. and I've got the discs to prove it.

[QuintinGellar]

those subtitles while he was explaining the mono thing in the beginning 😂😂😂😂😂😂 laughed my ass off. You're amazing man

[costa_marco]

Well played sir! Now I can't just skip directly to the puppets... ;)

[jimcogan]

Hello, really liked the video. Interested to hear about the chap who devised the Trimicron system and what he did before and after, and ultimately, what became of him. Possible idea for follow up video, maybe? Keep up the good work :)

[discodivo]

I have one CD in my collection that might interest you. It is an Italian bootleg of Duran Duran titled Return Return. I bought it when it came out in the 90s and was very surprised to discover that the total running time is slightly over 115 minutes. It is not a ''double mono'' recording on a single CD, the CD plays regularly on a standard CD player. Oh my! Did I just trigger another Techmoan episode? :)

[SuperHyperExtra]

I know, this video is two years old...
I have one of these Rodolphe CD boxset. Itʼs a recording of three Mozart opera (Don Giovanni; Le Nozze Di Figaro; Die Zauberflöte) by Furtwrangler (1951-53 performances on 4 discs). From what I read, I understand they released only three (!!!!) of these (Mozart, Beethoven, Wagner, and only this last one included a switch)...

[MrJmmy]

i used to have that same sony cd play man do i regret getting rid of it

this reminds me of some vcd movies i have left channel was English right channel was chinese

[joshuascholar]

The interesting thing about the length of the CD is the choice of sampling rate 44.5 khz and the claimed frequency response up to 20 khz was barely achievable when CDs came out. A brick wall filter that sharp can't really be done in analogue circuitry, and digital filters that could do it would be new chips that they had to design just for the purpose. The saving grace of it all is that it doesn't really matter. In fact 16 bit digital to analogue converters were also brand new and barely available when CD players first came out, so the first few CD players didn't have those either. So the point is that the some first few players wouldn't be able to quite live up to the standard in ways that almost no one could hear and that didn't matter. The technology would catch up with the standard.

[DaveSpagnol]

Playing "20 Greatest Hits" LPs, you notice that the volume is much reduced, they scratch easily, and even if they don't jump, the background noise is far greater in relation to the signal level. I don't think that the LPs would have lasted very long on the sort of equipment that most people had.

[ThomasPerl]

Well, MiniDisc had mono, and it was quite useful. Of course it was already built into the format, so every player would auto-switch.

Might have been really useful for e.g. CD Audiobooks. Of course, once MP3 CDs came around that players could handle, that made it even more flexible than just stereo vs mono (where MiniDisc went with MDLP for flexibility and later Hi-MD and MP3 support).