Impedance calibration level imbalance issues

[roger2]

I am using REW v5.19 which is installed on two PC's: one Win XP, the other W7 64bit.

Have tried several times and keep getting error messages as shown in the attached image (percentage of level difference varies). My impedance rig is new, is comprised of quality new (clean) Monoprice RCA cables with gold plated connectors. I have verified that resistance = 0 for the jumper I am using to short the sense resistor.

What might be the problem?

 

[John Mulcahy]

If the input channels have individual gain controls they might be set differently. The 5.20 beta versions are a bit more tolerant, allowing 5% difference, but that still wouldn't pass with your system.

 

[roger2]

Thank for your reply. I found some level controls, but was not able to make a fine enough adjustment with those to improve the input balance.

Is this a common problem with older computers? On both of my computers the sound card is integrated into the mother board. Or could this possibly be caused by an issue with my impedance jig?

Could I use some type of USB sound card or pre-amp? If I connect a USB sound card would REW recognize it automatically, or could I select it within Windows or REW?

 

[John Mulcahy]

Audio interfaces are recognised automatically, though if you connect them while REW is running it may take a minute or so to show up. If this is an integrated soundcard and the balance control isn't off centre there may well be an issue with the jig and its connections. For impedance measurements it is helpful for the audio output to have reasonable drive capability, so headphone outputs can be better than line outputs, for example. Output and input need to be on the same device.

 

[roger2]

I am using headphone out and line in, as per REW Help. And those connections are both on the same device, the integrated sound interface.

I will re-do my impedance jig. Perhaps one of my solder joints is less than perfect. If that doesn't solve the issue I will get some type of USB sound card or pre-amp.

Thanks again