For plenty of media center PCs, home theaters, and people with a simple TV and a decent audio system, the standard speaker setup now is 5.1 surround sound. Left and right speakers in the front and back, with a center speaker and a subwoofer. But the 5.1 setup wasn’t always the standard (and still isn’t the only standard); after stereo was adopted mid-century, audio engineers wanted more than just two channels and briefly attempted a four-channel system called quadrophonic sound. There’s still some media from the 70s that can be found that is built for this system, such as [Alan]’s collection of 8-track tapes. These tapes are getting along in years, so he built a quadrophonic 8-track replica to keep the experience alive.
The first thing needed for a replica system like this is digital quadrophonic audio files themselves. Since the format died in the late 70s, there’s not a lot available in modern times so [Alan] has a dedicated 8-track player connected to a four-channel audio-to-USB device to digitize his own collection of quadrophonic 8-track tapes. This process is destructive for the decades-old tapes so it is very much necessary.
With the audio files captured, he now needs something to play them back with. A Raspberry Pi is put to the task, but it needs a special sound card in order to play back the four channels simultaneously. To preserve the feel of an antique 8-track player he’s cannibalized parts from three broken players to keep the cassette loading mechanism and track indicator display along with four VU meters for each of the channels. A QR code reader inside the device reads a QR code on the replica 8-track cassettes when they are inserted which prompts the Pi to play the correct audio file, and a series of buttons along with a screen on the front can be used to fast forward, rewind and pause. A solenoid inside the device preserves the “clunk” sound typical of real 8-track players.
As a replica, this player goes to great lengths to preserve the essence of not only the 8-track era, but the brief quadrophonic frenzy of the early and mid 70s. There’s not a lot of activity around quadrophonic sound anymore, but 8-tracks are popular targets for builds and restorations, and a few that go beyond audio including this project that uses one for computer memory instead.
Shouldn’t 5.1 be sorta backwards compatible with quadraphonic? I mean, there’s the front and rear speakers, you don’t have to use the center…
In fact, if you connect just 4 speakers to a surround receiver it’ll down mix the channels with a faux center channel and sub mixed into the signal. That’s what I’ve been using with 4x DIY full range tower speakers playing stereo over quad speakers which already sounds really good. Some movies have surround music tracks, ie the title roll etc.
But I love to hear what the OP has captured from quadrophonic sources on my own system. It’s copyrighted material of course so I don’t expect that’s possible.
“This process is destructive for the decades-old tapes so it is very much necessary.”
Playback by itself shouldn’t be destructive. Maybe playback is destructive to deteriorated tapes, which would make recording on playback necessary to preserve the old content.
8-track tapes were pretty much self destructive when they were new. I saw more of the along the roadside than I ever saw being played.
There is still quite a bit of activity around quad these days- niche though it is. But many of those old quads recordings from the 70s have been or are still being released in digital formats (discs). Surround music has a hardcore following and has grown from quad to 5.1, 7.1 all the way to Atmos (5.1.2, 5.1.4, 7.1.4 even 11.4.6 and beyond since Atmos is object-oriented not channel-based).
I suggest you go over to quadraphonicquad.com and check out the forums filled with some of the nicest folks who know tons about surround sound- both vintage and modern- and music in general. We’re a small but fanatical niche in music appreciation. You’ll be surprised to see how much music has been and is being released in surround- despite many poor industry decisions that have often derailed the technology and market for surround.
Are the coins or other “shims” we used to jam under the 8 track cartridges digitized too?
You needed them to get the sound just right.
Matchbooks were the shim of choice where I grew up.
I read that as “Macbooks were the shim of choice”, and honestly a Macbook Air would make quite a good shim, abit an expensive one.
> A solenoid inside the device preserves the “clunk” sound typical of real 8-track players.
Love it. :-)
Am I the last living dinosaur that remembers building Dynaco kits? Best four channel stuff ever.
I built and repaired quite a few Dynaco units over the years. I still have my silver face 400 power amp and 70 tube amp.
👍. I have always used the simple Dave Halfler circuit. Take the positives of the front spkrs to the two rear positives. Then just connect the negatives of the rear channels together. Poor man’s 4 channel!👍
Yes that can work very well with UHJ encoded records produced by Nimbus.
also live recorded music from BBC. try it on the Proms. it can sit you un the audience.
I have used the early ’70’s DynaQuad out-of-phase ambience extractors feeding, from naturally recorded stereo LPs, rear speakers. The system vastly improved warmth and fullness, the listener being IN the sound field rather than on the outside looking in.
I found Guns and Roses greatest hits in 5.1 surround, not a big fan but (Laff,In) homey. Having done my 3rd place 1971 science fair project on the up coming quad standards, this many years later I’m ready. Just how mainstream is everything at hand? I play the file on my 4 speaker built in sound card setup quad amp and 4 speakers, it seems to be stereo? In VLC , audio menu. There is a dropdown list of mono, stereo(on), quad, 5.1, click on quad. On Knocking on Heavens Door the choir is spread across the back! Hallelujah! Quad at last. More speakers in the middle? No they tried 40 channels at once once, stereo has an infinite number “channels”.
From Switched On Bach on quad was the next thing. Most selling titles were mixed down to discrete 4 channel for the future. CD4 records were the greatest hope but after many plays the 40kHz subcarrier tracks faded out. 8 tracks were always at the bottom of any respectable setup except the car. Since the early 80’s every car has 4 or more amplifier channels and speakers but 2 channel front end even a 4 channel head-preamp for auto reverse. I had surround matrix in my father’s Oldsmobile in the mid 70’s.
Looking back through the 70’s, midway the creative decade ended and the final hope for quad was a could have been. Philips CC pushed compatibility within it’s otherwise great system that led to, if we can’t cram 8 total tracks in the two sides it’s no go. It was, physics limit. Quad on a single sided cassette would have been great and only get better till the CD which had a quad standard which never happened, logic decks would rewind before playing for long life. NO! It wasn’t till 80’s home studio 4 track would Phillips allow quad but there had to be a switch for normal mode. Too late. Most of the 4 tracks I’ve seen record 2 at a time and the 4 total tracks get a stereo mixdown in the box. No quad out!
I just picked up an old Heathkit quad receiver and a Sony quad 8-track player (were there recorders?) recently. They need recapping most likely. I’m excited to tinker around with them as well as using some current AI isolation tools to mix-down some old mono and stereo stuff to quad. So far converting the mono to stereo has been phenomenal.
Wollensak (sp?) made an 8-track recorder. It was expensive (IIRC around $1k in the 1970s)
SQ encoded Albums on CD, Dark Side of the Moon, Wish you were here, Machine Head, Tubular Bells, all have the 4 channel information encoded on them.
if you recorded Dark Side of the Moon onto cassette tape (we all did), it was still 4 channel
You mean the DSOTM CD I have right now has SQ encoded information on it?
Didn’t the BBC transmit the proms in quad? I’ve not checked lately, it may just be 2.0 Dolby now on their iPlayer
The initial problem with 8 Track tapes was the poor quality of the magnetic tape itself. They would deteriorated quickly due to being left in the vehicle and being effected by extreme temperatures. Secondly the felt cushion would
also deteriorate, causing poor sound. No one ever was taught to clean the players tape transport system, especially the capstan roller. There would always be a build up of debris that would cause tapes to be chewed up. Also no one was taught about head demagnetization. There was the head cleaners that were the same as the 8 track shell.
This was suppose to loop back and forth in cleaning the tape transport system. Instead it would only pick up minimal amount of debris and wear out the tape heads. After the demise of 8 tracks came the DBX Surround Sound System.
Very impressive but costly and CD’s were slowly taking over.
All I have to say is the entry to ZZ Top …. La Grange
And yes I’m a teenager of the 70’s