Ableton Forum

When I enter midi controller data via USB or firewire I get dropouts in audio. If I assign that CC to a live parameter then there are no audio dropouts. The problem appears even at very low CPU usage e.g. 15%.

This makes it very hard to enter CC data such as pitch bend or mod wheel without cracks in the audio, unless I put the buffer up to 1024 or so, which is too high to be useful for me. I'm aiming for 256.

What could be causing the dropouts?

Looking at this further, if I have an empty set, and I move the mod wheel of my midi controller, the CPU jumps from 1% up to 8%, even though no tracks are receiving midi input. But if i assign the mod wheel to any ableton parameter with midi map, the CPU only rises to 2% when I move the mod wheel. my buffer is at 256 samples.

Why should streams of midi data that are not assigned to control parameters use so much more CPU? Its causing dropouts at all CPU levels, when the buffer is 256 or lower, on a dual core iMac...

surprised no one came across this.

Its a bug, fixed in the new beta 8.2.b3