[Lifeboy]

I just bought a UMIK-1 from MiniDSP to measure my untreated, two channel listening room with REW. The end of the 10-20khz frequency sweep (about the last second) does not sound smooth. There is a wavering sound that sounds kind of like an ambulance siren that can be heard over top of the sweep. I tried stereo, just the left channel, and just the right channel and it's always there. Does anyone know what could cause this? Can it be some kind of weird room interaction?

Thanks in advance for your help!

 

[JohnM]

It might be that some part of the audio path is operating at a lower sample rate than REW is set to and the sample rate conversion is resulting in aliasing at the top end of the sweep. Check what sample rate the output device is set to in the OS.

 

[Lifeboy]

Wow, you're good! That's exactly what it was. I changed it from 44 to 48 and the problem is gone. Thank you very much! Now I can start measuring the room!