# Using Timing Reference with USB devices



## Primare Knob (Dec 4, 2014)

Does any one know how to setup Time Reference in REW when you are not using a physical audio card. Is there a software driver or mixer where I can set this up?

I am using the Dayton UMM-6 mic and a USB DAC as my audio devices.


----------



## Wayne A. Pflughaupt (Apr 13, 2006)

Maybe John or someone better qualified will chime in, but my understanding is it requires a loopback in order to have a timing reference, and it can’t be done with USB devices.

Regards, 
Wayne


----------



## Phillips (Aug 12, 2011)

As far as I know Wayne you are correct.

Think John might be working on something though?


----------



## AudiocRaver (Jun 6, 2012)

That is the correct answer. An audio interface with one channel dedicated to the loopback function is required.


----------



## AudiocRaver (Jun 6, 2012)

It should be possible to create a pseudo-loopback using a PC's headphone output and mic or line input with the right cable and settings, should allow accurate RELATIVE timing measurements but no ABSOLUTE timing reference. This could be useful for matching reflection path lengths, etc, where the absolute accuracy does not matter. Have not tried it yet, might take a special cable/adapter combo.


----------

