VCA automation and analog synths

[Unfiltered]

I work with a SSL 9000 analog console, and learned that the mechanical moving faders work by control voltage. The CVs are recorded as data onto a floppy disc. But when you play back the automation, the faders move and you get a smooth fade, because the data stored is only changes in CV, not the CV themselves. Its pretty simple when you think about it, but then why cant the manufacturers of analog synths produce a similar system? It seems like to me when using midi data to change parameters, its almost always unusable (unless youre going for that effect) because of stepping. I have not used the Volta program, so I dont know how smooth the sweeps are, but it seems like storing and playing back smooth sweeps are a large void in the analog domain, and maybe something like the SSL automation could be the answer. Has anyone used Volta, and can they attest to the smoothness of its sweeps?

[museslave]

Well, it could be because most analog synths already have VCA automation in the form of the envelope generator?

[theglyph]

There's the Modcan CV recorder module and the Flame Clockwork can record its CVs in a limited capacity (plus they have a knob recorder on the horizon). I haven't tried Volta but I hear it generates relatively smooth CVs.

[EMwhite]

It has to do with whether or not the synth (and recording mechanism aka sequencer) is 14-bit midi capable. Standard 7-bit midi will only store values of 0..127 and as you said, "stepping".

The latest Phatty-line code (3.03) supports 14 bit midi but that doesn't mean that every CC will map appropriately. You're DAW, hardware sequencer, or Midi controller kbd must also support it. See the Slim Phatty documentation and specifically the 3.03 release notes.

[Kevin Lightner]

Fwiw, volume (VCA) stepping is usually less noticeable than pitch or filter CV stepping.

[Unfiltered]

Yeah, something about the inability of the ear to differentiate close tones makes pitch bend more usable for digital. As for the EG, I understand what youre saying but is it possible to get automations on an analog EG that last several minutes? But my point and question is that why cant a hybrid synth like the phatty or something store changes in CV and play them back with variable glide time (like the SSL )? It seems like a feature that would have made its way to analog synths as far back as the 70s, when VCA automation on analog consoles was invented, especially by Oberheim, who was into the hybrid stuff early. Maybe they were all blinded by the MIDI storm. All of the SSL 9000:s automations for entire mixes can be stored on a small floppy. Would have been easy to implement on a synth.

[Kevin Lightner]

In the '70s, memory was very pricey.

[HowardJones]

You can to some extent overcome stepping by sending the offending CV via a slew limiter. I've resorted to that before.

[Kevin Lightner]

Another way might be to use the full CC range of the voltage, but then attenuate it before it reaches it's destination.
(A range of 5 octaves using 127 steps is quite noticeable, but 2 semitones using 127 steps might not be.)