MATRIXSYNTH: L-1 Discrete 16-channel Vocoder. Distorted waves.

Wednesday, June 12, 2024

L-1 Discrete 16-channel Vocoder. Distorted waves.

video upload by Aleksei Laman

"I used two distorted saw waves as carrier."

You can find additional demos in previous posts here.

Pic and details via

"The module is 28HP. 3 stacked boards deep. Control board, odd channels filterbank board, even channels filterbank board.

I used my Discrete Blacksea VCAs everywhere - in channels, input compressor, output mixers. So 23 VCAs total. Microphone preamp is THAT1512 based.

Modulator has two inputs. First from a microphone with Gain knob. Second for other sources with level attenuator knob. There is an output after mic preamp to send a voice to external processing then return into MOD input.

Then modulator signal goes to compressor. Attack, release and ratio setting are fixed. Threshold sets with a knob.

After the compressor it goes to 16-channel filterbank.

Carrier has two inputs with attenuator knobs. Also it has Gain knob which can add up to x6 gain to both inputs together. It's for using quiet line level signals.

LEDs show when compression applied, when modulator and carrier inputs overloaded, when Noise Gate closed and open.

Filterbank has separate outputs for odd and even channels. Filterbank VCAs have semi-exponential response. This easy to trim but I think semi-expo is ok. Every filterbank channel has level trimpot. Normally trimming is not needed. But if someone wants to make some channels quieter or louder - it's possible.

Two switches set normal or alternate order for odd and even channels. Normal order when 1st madulator channel drives 1st carrier channel, 2nd-2nd, etc. Alternate order sets with jumpers at the board. Every channel at the board has a jumper which sets which carrier channel drives this modulator channel. So possible to make unusual combinations. It what was realized with patchcables at Moog Vocoder.

Noise Gate mutes filterbank output when no signal. Because 16 channels mixed can create noticeable background noise.

At the output 3 stereo mixers are installed. First for clean voice coming from mic amp and MOD input. Second for odd channels, third for even channels. All mixers with VC level and panorama.

Also there stereo send-return in/outs for adding effects. The idea was to make some spatial effects. For example - clean voice at the center, odd channels at the left, even channels at the right. And vocoder channels rotate modulated from external LFO. Even channels panorama CV input is normalled to odd pan CV input through an invertor. So this rotating effect is possible to make with single LFO."

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