CV Overhaul

Ok, I tried to demonstrate the Force's CV output 4+ ms jitter behavior with an oscilloscope.



There's a steady stream of notes, note-ons spaced at 32nd notes, and the length of each note is a 64th note. The tempo is 520 bpm. If the CV output was ideally accurate, the width of each CV curve pulse should be 7.2 milliseconds, and the space between rising edges i.e. note-onsets should be 14.4 milliseconds. But if we look at the cyan CV curve, we can see that the pulse edges are quantized to about 4 ms time quantums. Sometimes the pulse is about 8 milliseconds, sometimes it is 4 milliseconds. The note spacing is always either 12 or 16 milliseconds.

On the second channel, shown in yellow, there's the Force's audio output, coming from a drum track, to which the CV track sends its MIDI notes. The drum track is playing a very short loud snap sample. There is no jitter in the audio, the note spacing is about the 14 milliseconds it should be.

I wonder what CLOCK DIVIDER means in the new UI graphics. Is it for macro-scale sequencer control, or could it allow specifying a custom rate for what currently seems to be a 240 Hz timer updating the CV outputs? Maybe something completely different.

running samples thru vintage analog (Moog, Korg, Roland) filters and layering it with analog osc'S opens a new universe and jus sounds awesome

had to come to the forum to see if there was any talk of improved CV implementation and was glad to find this thread. the new workflow alone is already making this more attractive than my Octatrack + CV OCD setup i've been trying to use

I think it would be really cool if MPC offered some CV plugins. What i'd really want to see would be Akai partnering with VCV rack to add that to the MPC. Maybe a charge to integrate the two, and the VCV sub to use the paid modules. I got the MPC one for live use, I think this would make this thing incredibly powerful for modular while decreasing the amount of gear you'd have to bring out to a show. 4ms just did something similar with the new "meta module" and it seems like it would integrate perfectly with the MPC

Yo you're the one I talked today with on FB are you ?

diabolik! wrote:had to come to the forum to see if there was any talk of improved CV implementation and was glad to find this thread. the new workflow alone is already making this more attractive than my Octatrack + CV OCD setup i've been trying to use

I think it would be really cool if MPC offered some CV plugins. What i'd really want to see would be Akai partnering with VCV rack to add that to the MPC. Maybe a charge to integrate the two, and the VCV sub to use the paid modules. I got the MPC one for live use, I think this would make this thing incredibly powerful for modular while decreasing the amount of gear you'd have to bring out to a show. 4ms just did something similar with the new "meta module" and it seems like it would integrate perfectly with the MPC

dustyslices wrote:Yo you're the one I talked today with on FB are you ?

diabolik! wrote:had to come to the forum to see if there was any talk of improved CV implementation and was glad to find this thread. the new workflow alone is already making this more attractive than my Octatrack + CV OCD setup i've been trying to use

I think it would be really cool if MPC offered some CV plugins. What i'd really want to see would be Akai partnering with VCV rack to add that to the MPC. Maybe a charge to integrate the two, and the VCV sub to use the paid modules. I got the MPC one for live use, I think this would make this thing incredibly powerful for modular while decreasing the amount of gear you'd have to bring out to a show. 4ms just did something similar with the new "meta module" and it seems like it would integrate perfectly with the MPC

Oh nah that wasn’t me, has someone else been talking about wanting the same features? I hope so, maybe someone at Akai might notice

I'd be down for VCV Rack on the Akai or other custom CV Plugins

MPC 3.0 has a feature request form ..... we should probably send it to them.... will definitely use the CV pages that were uncovered in this thread.

@HouseWithoutMouse was this filed as bug with Akai? We might want to put it it their radar, maybe they can tighten up the code around cv, unless it's hardware based that is causing the delay.

it's not a bug, it's just a way the code is structured, besides CV is at the far end of MPC ecosystem priorities, way behind new plugins, audio, midi and other stuff

If it's really driven by a timer interrupt, maybe the rate could be set to, say, 1000 Hz, reducing the jitter to at least the same level as USB MIDI. Supporting DC coupled USB audio interfaces as alternative or additional CV outputs could be good too.

Is the constant non-musical 4 ms jitter bad? I think it's not good for rhythmic things. What would you think if the MPC random-quantized the timings in all your drum tracks by 4 milliseconds as a non-optional service? For comparison, here's Korg Volca Nubass's sync out jitter measurements viewtopic.php?p=1853476#p1853476

HouseWithoutMouse wrote:If it's really driven by a timer interrupt, maybe the rate could be set to, say, 1000 Hz, reducing the jitter to at least the same level as USB MIDI. Supporting DC coupled USB audio interfaces as alternative or additional CV outputs could be good too.

I believe this works with teh MPC

https://www.expert-sleepers.co.uk/es9.html

Yes something like that, but I think you can't currently specify a USB audio interface's output port for a CV track, it's limited to the MPC's CV outs.

Hopefully if they are going to add Envelopes and LFOs, they'll expand the options on outputting CV through hardware.

Neodymium wrote:Hopefully if they are going to add Envelopes and LFOs, they'll expand the options on outputting CV through hardware.

AKAI is testing to expand cv options for a while already - as there was a non public "alpha or beta" version for interested beta testers. Originally it was for the force (iirc), but since the force and mpc are getting closer to each other OS wise, I feel very optimistic that we will see more CV options sooner or later.

Thanks for sharing!!
This is amazing really - hope they fix my “dealbreakers” with 3 by the time they implement this. As someone who uses MPC’s CV/Gates all the time, I hope they fix the issue where changing a track impacts all sequences in a project, and the missing “beats per track” option first.