Dream Analog Sounds: The Logan VocalSynth

Video timestamps

 

00:00 intro

00:25 voice - choir

01:49 polyphonic synth presets and free mode

03:09 musical interlude

04:16 monophonic synth presets

04:50 monophonic synth free mode

06:14 white and pink noise

06:35 monophonic synth freak out

08:52 musical interlude 2

11:06 string machine

11:25 assigning sounds

13:01 one final sonic exploration

We finally found a Logan Vocal Synth - it's kind of incredible. Very few artifacts were available online apart from a few Ebay auction photos from 10-15 years ago - shoutout to Matrix Synth for all the archiving through the years - and a brief demonstration video by our dear friends Marco and Andrea here on the Tube.

 

Since this unicorn doesn't get captured very often we thought we owed the internet some quality photos and a more in depth and technical video demonstration of its functions. There are a lot of features here so we actually missed a few, so stay tuned for a Part II maybe later this summer. This instrument is really inspiring so we also ended up making a couple of songs of which a few are included in this video but some were left out to keep things snappy. Most of the performance info and some technical details are in the video already as text but a quick introduction and recap would go something like this: Logan Vocal Synth

 

The upper panel is dedicated to : instrument selection buttons and Voice vowel sound selection, panning left and right, the monophonic and polyphonic synthesizers presets, volumes and modulation controls. The front of the panel is dedicated to the volumes, attack and decay controls of the instrument sections Strings, Piano and Voice and their distribution to each side of the keyboard split point. The architecture of this instrument is unique and might have been a bit of a gamble that sometimes worked out great and other times less so.

 

Our service technician had to slightly change the trigger circuitry to render the triggering of the notes more reliable and generally stable. We also decided to non-invasively modify the two octaves below the split point to continue down to the lowest note on the keyboard instead of starting over two octaves up - essentially repeating the range of the 2 octaves above it. This rather odd engineering choice might have been a remnant from a double manual, organ approach to the keyboard that perhaps was scrapped late in the engineering process.

 

You change to the modified "normalized" note distribution with the foot pedal switch, and it can be disengaged to return to the factory setting. Our service tech also had a "tester board" with an extension connector cable custom made to more easily test components without having to continuously pull out the boards one by one. This was a game changer during the long service and restoration. The Vocal Synth does have an empty card slot so it's likely it came equipped with a similar tester board from the factory. We also installed LEDs to each circuit board - that lights up when in operation - to see which card the master oscillator distribute commands to - just like you would to a Yamaha CS60 or CS80 - although they are quite a different animal the technical principle is the same.

 

Some of the engineering wonkiness was decided to be kept intact and you can hear the fluctuations, a slight tremble, on a lot of the sounds.

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