Two simultaneous inputs - one compresses the other

I setup an audio track for vocals (or sometimes I have an audio input from my iPad to play along with music from my iPad).

I setup an instrument track for a virtual instrument.

 

With both armed, when I play the virtual instrument the volume output of the audio track drops. As the virtual instrument fades out or stops the audio track starts rising in volume. This is driving me crazy and I never noticed it before.

 

I tried removing all third party plugins and only used Logic built in and it still does it. I also tried changing audio interfaces-still there.

 

I can't reproduce this in any other DAW - both tracks maintain a consistent volume. Any clues as to what could be causing this?

What happens if you try with no plugins at all?

What happens if you try with no plugins at all?

 

Same thing. Had iPad output setup on one audio track, a mic on a second audio track. I started the iPad playing music at a good volume. I would say a word and the iPad volume dropped dramatically and then slowly started to rise until it returned to the original volume.

If you're recording and playing at same time on the iPad it's never gonna work because the iPad is automatically ducking the other track.

If you're recording and playing at same time on the iPad it's never gonna work because the iPad is automatically ducking the other track.

 

I wish that was it.

 

It doesn't do that in Reaper (I tested Reaper to see if it was Logic specific) and it used to not happen in Logic. Note "ducking" also happens in Logic with a Vocal mic and a virtual piano. If I sing and play it ducks in and out. Again, it just started doing that. I'm puzzled.

Ya got me. If there are no plugins doing the ducking, my only other thought is that audio is going back to your interface and causing some ducking. Seems kind of far-fetched though. With no plugins and routing straight to the output, Logic shouldn't be able to affect the relative levels of its channels like this.