REW Beta Release Bass roll-off in measurements in new REW

[ElixBerd]

Hi! I'm new to the forum. After updating REW to the new beta 39 (I was using beta 19, I think) all my measurements are different in a particular way: there is a bass roll-off on all of my measurements. I am measuring in-ear monitors. Hardware hasn't changed, i.e. the IEM is the same, microphone is the same (I even replaced the battery) and my DAC/ADC is the same with the same parameters. I also used the same calibration file and same measurements settings. I made certain that there were no leaks between the silicon tip and the coupling chamber, I mean I tried different tips and IEMs, and the results are consistent - the bass roll-off persistst. You can see it in the attachment.

On the attached image, red graph corresponds to the old measurement of that particular earphone, green is the new one. Difference above 1kHz is due to different tip and insertion depth, but that's not relevant to my question.

So I'm out of ideas and I need your help. Thanks!

 

[John Mulcahy]

Can you attach an mdat file?

 

[ElixBerd]

Sure!

 

[John Mulcahy]

The latest measurement is inverted compared to the earlier ones, which suggests something might have changed electrically. Try a single sweep instead of 2 sweeps in case there are any synchronisation issues between the sweeps, but there don't look to be. The mic, its bias supply and its preamp are probably the most likely areas.

 

[ElixBerd]

The latest measurement is inverted compared to the earlier ones, which suggests something might have changed electrically. Try a single sweep instead of 2 sweeps in case there are any synchronisation issues between the sweeps, but there don't look to be. The mic, its bias supply and its preamp are probably the most likely areas.

Thank you for your insights! The only thing I remember that could've changed between those measurements is that I had a new electrical outlet made. So I just swapped the plug of my ADC, and measurements went normal.