MATRIXSYNTH: Vintage Bell Labs Digital Synthesizer 1977 Demo Video by Creator Hal Alles

Monday, June 15, 2015

Vintage Bell Labs Digital Synthesizer 1977 Demo Video by Creator Hal Alles

Vintage Digital Synthisizer 1977 Published on Jun 15, 2015 urcich

Roger Powell at 5:22. Further below is a video of Laurie Spiegel playing the synth. See the Bell Labs channel label at the bottom of this post for more.

It's fascinating to hear what the initial intent of this synthesizer was.

via Hal Alles on the Synergy list:

"Since a few people have expressed interest, I posted a video on youtube of a demo using the synthesizer I developed at Bell Labs.

This demo was made as a backup for a live demo for the celebration of the 50th Anniversary of Talking Motion Pictures.

Hence the references to the movie industry.

The live demo was done on the stage at the Palladium in Hollywood in 1977, so the backup was never shown.
It started life as studio video tape made a few days before the show, converted to 16 mm film, then later to VHS tape, then to DVD, and finally the digital version posted.

Very few people have seen this – I did not have a copy until 1995.

Hal Alles"

Laurie Spiegel plays Alles synth - temporary replacement

Uploaded on Apr 27, 2009 Laurie Spiegel

"This 1977 tape is one of the earliest examples of purely digital realtime audio synthesis. It manages to achieve an analog synth sounding quality, but it is entirely digital synthesis and signal processing.

The interactive software I wrote and am playing in this video recycles my keyboard input into an accompaniment to my continued playing, which is why I called it a "concerto generator". I use part of one of the keyboards for control data entry, and the small switches upper right to access pre-entered numerical patterns. The sliders are mainly pre-Yamaha FM synthesis parameter controls, for the number of harmonics and amplitude and frequency of the FM modulator and carrier that constituted each musical voice.

Until they restore the copy suffering from data corruption please look at this copy instead.

Comments can continue to be left on the original's page where there have been many views and comments views, here:

Thanks for watching,

- Laurie"

Update via Spiegel's Reflections in the comments: "I've posted some additional info about the synth Hal Alles built that's featured here along with a link to more technical info. See my extended comment near the bottom of this page":

"I never heard this called "Alice" till the last couple years. Don't know when that name first surfaced.
A correction: This was at the time considered the world's first ***realtime*** digital (not "additive") synthesizer. Yes, it could do additive synthesis but was quite flexible as to how the oscillator could be used. I used them as FM pairs, with both the modulator and carrier of each FM pair being additive, with the number and amplitude of their harmonics controlled by the slide pots. (This video of me playing it shows is a rare example of pre-Yamaha DX-series FM synthesis.) The breakthrough was to do digital synthesis in realtime so it could be interactive. Prior to this technology, digital computers were not fast enough to produce audio in real time and it was not possible to do digital audio interactively.
There were 72 slide pots. (72 oscillators were mentioned above instead). The number of oscillators depending on how the components were programmed to interconnect. For the specifics of its synthesis architecture, please see Hal Alles's paper describing the system in Computer Music Journal, Vol. 1 #4, which you can find on my website at
The system was not dismantled as it says here, but donated to the Oberlin College Music Dept. For all I know it is still there. I'm not sure why Gary Nelson and the group there were not able to get it running. I had heard that it was dropped during the move, but alternatively, we programmed it remotely from (if I remember right) an LSI 11/45 computer in another part of the Labs. I don't know to what extent it could be programmed independently of an external computer with a compiler etc. installed, so that might have been a major hurdle for them. This was 1977 at Bell Telephone Labs, so the purpose of the system was never to make a marketable music system but to develop and test the new designs of its components, and I was under the impression a bunch of new patents resulted, The ideas built into this instrument were not lost to music though. Crumar created various synthsizers based on its internal architecture. I think (but am not sure because I never had direct experience with them) that those included the Crumar GDS and Synergy.
From the liner notes of my 'Obsolete System' cd:
This composition was commissioned by Bell Labs and the Motion Picture Academy for the 50th anniversary of talking pictures. Working with the Alles synthesizer, with its extensive array of input and output channels for control, was a real pleasure after years of GROOVE's extreme restrictions. The interactive software I wrote for this composition recycles the player's keyboard input into an ongoing accompaniment. However, writing the software from a remote DEC PDP-11 computer [..] in the new "C" computer language still undergoing frequent change, within a still-experimental UNIX operating system, without the control inputs or sonic output, under a tight deadline, while the Alles synthesizer hardware was still under construction, turned out to be quite an adventure.

It's also not necessarily true that only 1 composition survives from this instrument. Roger Powell also composed something on it I believe, though I don't know if he finished or recorded it. And I have a couple of reel-to-reel tapes I recorded on it that I haven't listened to since then (1977). It is possible that something on one of those open reels might be worthy of being considered additional music. At some point I will work up to transferring them to digital and find out."

1 comment:

  1. I've posted some additional info about the synth Hal Alles built that's featured here along with a link to more technical info. See my extended comment near the bottom of this page:



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