Latency bug - recorded audio 1ms early

[RuLemer]

Hi there,

I'm totally stumped.

I'm trying to accurately measure the latency of my system for research reasons. I send a signal from MacBook Pro (10.12.6) running Pro Tools 12.8.2 out of my Scarlett 18i20, then using a cable I plug the signal back into an input. When I record this input, the recorded signal is 1ms earlier than the waveform of the original signal being sent out

This doesn't change when I relaunch PT, when I try at a different sample rate, with delay compensation on or off, with a different signal, or when I change the hardware buffer size

There are no plugins being used, and no h/w insert delay

My rig is prophetic!!

I can only presume there's some sort of automatic latency compensation going on that is malfunctioning. Anyone know anything about this or how to turn it off?

Thank you kindly for your time!

~ Ru

[Bob Olhsson]

Recordings are always moved to compensate for whatever latency that the interface reports. You should contact Focusrite about this.

[RuLemer]

I've talked to several people about this now and they've reported this issue amongst several other USB interfaces. Although it doesn't occur in my firewire Fireface 800

I spoke to Focusrite about it - they say it's out of their control and to do with Pro Tools' interaction with the playback device. DAW's like Logic have included a manual control for compensating for the RTL time, apparently Pro Tools have chosen not to to encourage users to use Avid hardware, which of course works perfectly

If this is the case that it's a real bummer! Especially as I can't find any RTL figures available to the user at all. Even in my session settings window the overall latency shows as 0 when using my USB interface

[Bob Olhsson]

That would be a good suggestion to make on http://protools.ideascale.com/.

[DIRX]

On the Input tab of I/O setup, there is a checkbox "Compensate for input delays after record pass"....
that should turn it off.

Cheers,
Dirk