I have an old SRS stereo imager plugged into my Focusrite Scarlett 18i20 interface. Every time I open a session, I have to manually re-measure the latency to the device. Some sessions it’s in the 0.10ms range, other sessions it’s in the 0.18ms range. Sometimes it’s even as high as 0.30ms. If I don’t remember to set it manually on startup, the inconsistency will cause just enough phase issues in my mix to drive me nuts.
I’ve noticed that the longer it’s been since my last system reboot, the more likely it is I’ll measure a higher latency. I speculate it may have something to do with sleep/wake cycles, but that’s just a shot in the dark.
Also, and I don’t know if this is a related issue or not, but sometimes I lose the ability to measure latency through the little Cubase outboard device insert. I click the button, it sends the ping, I can see it on the send/return busses on my interface, but Cubase measures it as 0ms. When this happens, eventually Cubase will simply stop sending the ping when I click the “measure delay” button. I don’t know what’s going on there.
Edit: Prior to writing this post, I rebooted my system, opened my session in Cubase, and measured the latency to my SRS 6-8 times. It was a very consistent 0.10ms. Then, I wrote the above post, minimized Chrome, and measured 6-8 more times. The latency is now a very consistent 0.28ms. In my experience, this is enough of a difference to cause strong phase coherence issues. Anyone know what’s going on here?