REW Soundcard calibration – unexpected low frequency lift with Roland Rubix22

[herrturtur]

Dear forum members,

I was advised at Gearslutz to move my theard here:

I am using REW V5 with my Roland Rubix22 USB-Interface for the first time today. When calibrating the interface, there is no low frequency roll-off showing. There is actually a low-frequency rise starting from 10 Hz downwards (about 1.7dB peak at 2 Hz). (see pictures attached)

I am wondering what that means for measurements / what it says about the Rubix22 frequency response? This curve occurs at both line inputs of the R22, I also switched cables out of curiosity.

Here you can see my settings:

Level matching:

When I calibrated the UA Apollo 8 in our studio, it looked just like in the REW manual (low frequency roll-off below ca. 10 Hz).

Thanks for some advice, the manual only discusses feedback cases, but not a "missing low frequency roll-off". Also couldn't find anything on the web, yet.

Regards, Julian

 

[John Mulcahy]

Can you attach the mdat file, Julian? Doesn't look like anything untoward, an interface won't necessarily show a roll-off. If it is DC-coupled with servo offset control the roll-off could be at a very low frequency, below 0.1 Hz.

 

[herrturtur]

Thank you John for this quick reply! Here's the mdat file. Please note (if you looked at the measurement curves) that all the measurements fall off in the low frequency area rapidly - this is due to the limits of my home speakers (small Genelec 8010s). The missing roll-off from the R22 does not have anything to do with the measurement curves, but I'm sure you'd have figured this out yourself ;-) I only wanted to run some tests here.

Cheers, Julian

 

[John Mulcahy]

All fine, just a very good interface

 

[herrturtur]

Thanks, good to hear! Lately, I was disappointed from the interface, because the line outs are impedance balanced only - at least, the inputs seem fine