CPU spikes and buffer drops in Ableton Live via bridge

So I tried to set-up VCV rack with ableton Live via bridge and encountered this problem.

Everything seems to be working fine but as soon as I press the play button on a midi sequence or a piece of audio it causes a cpu spike, glitch and buffer drop when the loop ends.

Using the stand alone version works like a charm.

Any ideas?

VCV Bridge is deprecated and unsupported. You should wait for the upcoming Rack plugin for DAWs.


In FL Studio it works fine if you set the checkbox “fixed buffer size” in the plugin wrapper options… I assume the same might work in Live. With this option it runs quite nice, but still adds a bit of latency and needs 10% CPU (of one core, I assume).
If you’re lucky your soundcard can route outputs back to inputs, which let’s you use Rack with a DAW with 0% CPU, but this still adds the same amount of latency (4x the buffer size).

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If you’re on a Mac, use the Audio Unit. It loops properly but you can only use 2 channels at a time… or otherwise Soundflower seems to work.

Hi.I just found out that for some reason the Loop switch on Ableton Live was generating this issue. Every single time the loop re-started It would generate a buffer drop. Thanks for your replies.

yes thats correct, it is the loop point which causes the stutter on playback. i’ve not had time to test it across other DAW’s but i have read similar reports which suggest this is the case.

using the AU on the mac seems to be the current workaround but is limited to 2 channels, other than using soundflower (Mac) or Rearoute (PC with Reaper) which would enable more channels…

Is there an ETA on this Rack plugin for DAW’s? Will it allow CV to be sent to DAW’s?

CV sent within your computer is an audio signal. Rack can obviously send it; can your DAW receive it? I think Bitwig can (I don’t own it); of things I do use Live 10.1 with the new CV Tools package can, Plogue Bidule can, standalone Reaktor can. You need a tool to route it (you don’t want to risk sending DC to your speakers). On a Mac I use Soundflower or Loopback.

ETA for Rack for DAWs is shortly after Rack 2.0 is released, which is estimated for December 2019.

You’ll be able to send MIDI and audio to the DAW, so you can plugin CV signals into Audio’s inputs, or into CV-CC’s inputs. How your DAW handles these signals is dependent on the DAW, but I’ll assume that since you’re asking this question, you know how your DAW will handle it.