Unable to calibrate Impedance

[derhelle]

Hello everyone

I am new to REW and I'm trying to calibrate my impedance measurements.
But I got stuck at the open circuit measurement already.

My setup: MacBook Pro, Behringer UCA202 Soundcard, the t.amp PM40C, and a DIY Arta board.

The error I am getting is: There is a timing offset between the channels of 1.01 sample periods, this should not occur, check the sound card connections

Does someone know what the issue could be or where to beginn to debug it?
Would switching to Windows help?

 

[John Mulcahy]

Pretty unusual to have a 1 sample delay between input and output. What interface are you using?

 

[derhelle]

I am using the Behringer UCA202
Maybe the arta switch box i built is the problem? I dont have any soldering experience, could it be that a mistake on that board has an effect on the delay?

 

[John Mulcahy]

Make sure the monitor switch on the interface is off. The UCA202 has issues with low frequency crosstalk that give poor impedance results at low frequencies.

 

[derhelle]

Thanks for the reply.
The monitor switch was off. Should I use another audio interface?

 

[derhelle]

I installed REW on Windows as well to test it with the same setup and got the same error.
Does it make sense if i get a Y-splitter cable to test the audio interface only (L-Out to L & R-In directly)?

 

[John Mulcahy]

Probably better using a different interface. If either of the computers have headphone output and line input on their built-in audio you could try that.