L8.0.4 - Arming midi track adds phasing/flanging

[8O]

I have a midi clip which is looping. Audio is set to master. One send is activated at about 70% and on that return channel is the "Radio Gaga" effect preset.

When the clip is playing and I arm the track, the sound changes to add more high tones in a sort of flanging/phasing effect. This change only happens when the return is routed; if the send is at zero, arming the track on/off doesn't change the sound.

I cleaned up the set to remove all other devices and effects and it still happens.

This can't be right. What's going on? Why would arming a midi track change the sound quality?

(I would share the set for testing, but I got a "compressed file" warning with the share dialogue... )

L8.0.4 / OSX 10.5.7 / Motu Ultralite

[8O]

I have found the same effect with at least one other effect in the return track, e.g. with the Vinyl Distostat preset. Again, arming the midi track on/off causes phasing/flanging.

In both cases, I am using the stock Ableton effect presets at their default settings.

[8O]

I think the common denominator here is the Live 8 Saturator. I think this is creating the dependency on the arm state and also contributing to the clicking when arming on/off. Other devices e.g. overdrive, redux are working perfectly.

[8O]

More info... just seen (well, heard ) it happening on a drum track. Midi track containing drum rack is playing fine with audio going to master as well as a return track (with no devices at all on the return track). As soon as I hit arm on the drum track you can hear a couple of milliseconds delay between the midi track and the dry return track.

This is, as Depeche Mode said, "WRONG!"...

[[nis]]

This might be a playthrough optimization problem. As soon as you arm a track for recording or set the monitor switch to "IN", Live will disable the latency compensation for this track, so that you can play it with the lowest possible latency. As your return track is still compensated, you'll hear a flanging effect.

You can turn off the playthrough optimization with an Options.txt entry ("-StrictDelayCompensation"). This would avoid these problems, but then you will always get the latency of the entire set (i.e. of all other plugins etc.) when you play an instrument via MIDI. You could also turn off the latency compensation completely, but I'm not sure if you really want this.

Best,
Nico

[8O]

Cheers for the explanation, Nico, that helps a lot to understand what's going on.