Unexpected Low-Frequency attenuation in measurements

[tcoor8325]

I have a measurement discrepancy between two audio measurement software systems, REW and Audiomatica's CLIO12. Below are screenshots of the exact same measurement of the transfer function of a headphone cup. REW (Blue Line) looks very similar to CLIO (Red line) except for <150 Hz. The issue now, ofc, is that Idk which one is correct. My gut says that REW is wrong and CLIO is right, because I don't think I hear this high-passed feature. For both, the source is a 16k log sweep, with 1/12Oct smoothing. The only DSP difference is the source level, and acoustically these are different seatings on the same HATS. I'm frankly just worried that I missed a setting somewhere. Feel free to ask me more questions about my setup for debugging.

Thanks!

 

[tcoor8325]

Note: When output is routed back to input, both CLIO and REW show perfectly flat lines.

 

[tcoor8325]

Another Note: My REW Audio insterface is a Focusrite2i2. CLIO is its own audio interface and software.

 

[John Mulcahy]

Probably best attaching the mdat for the REW measurement, easier to check settings that way.

 

[tcoor8325]

Sure!

 

[John Mulcahy]

Settings look fine, there's nothing you could set that would roll off the low end in any case. An air leak from the seating seems the most likely culprit.