Audio-rate modulation using Tracktion LFOs?

[Lava]

I was playing around with the LFOs in Tracktion for the first time, and was a little disappointed to see that they only go up to 20Hz. It sure would be cool if they could go into the audio range. I'm imagining FM'ing the oscs on my Bass Station II via MIDI CC. I haven't done the calculation, but is there any inherent limitation of MIDI/CCs that would prevent audio-rate modulation? Is the bandwidth/resolution there to do such a thing?

[VariKusBrainZ]

Midi won't do audio rate, audio will though.

A simple Google will tell you all you need to know, I just checked for you

[fromwithin]

MIDI operates at 31,250 baud (bits per second). The data is formatted as 1 start bit, 8-bits of data and 1 stop bit, thus giving 3,125 bytes per second. You'd need two bytes for a Control Change, one for the CC# and one for the value. Thus, the highest frequency LFO you could send (as a square wave) is (31250 / (1 + 8 + 1)) / 2 = 1562.5Hz. And that's if you didn't send any other MIDI data out whatsoever.

[Lava]

Thanks! What about MIDI over USB? Obviously USB is much faster, but is there still a (non-USB) bandwidth limitation inherent to the MIDI protocol on a USB bus?

[fromwithin]

I've just been through the USB-MIDI spec and it's really designed to transfer MIDI packets over USB with a view to them eventually being treated as standard MIDI again. The spec includes the concept of virtual MIDI cables to be able to send multiple sets of 16 MIDI channels over a single USB connection, the idea being that USB's high speed can send data to multiple MIDI OUTs at simultaneously. There's nothing in there to preclude using the protocol to talk directly with a synth over USB, but MIDI is a real-time protocol. The MIDI messages don't include any timing information whatsoever. When a device receives a message, it executes it immediately and this makes it awkward to keep everything in sync if data is being sent at different rates to each device. This especially true when USB is involved:

https://vimeo.com/30913010