non-linear measurements

[grignacarbo]

hi, I recently bought the motu 828x audio interface to make measurements with rew but the frequency response is not linear, it seems that the high frequencies are cut off and I assure you it is not the fault of the room, with my old audio interface not this was happening. I made the measurements with multiple microphones, but the problem persists. Could it be the audio interface's fault? if so, does it mean that the motu audio interface is defective?

 

[John Mulcahy]

Looks fairly typical for a listening position measurement, can have a closer look if you attach the mdat file. You could make a close mic measurement on the tweeter axis if you are concerned about the HF output. If you want to check the interface make a measurement with a cable connected from output to input.

 

[grignacarbo]

I have attached the measurement file, consider that I tried to make the measurement by positioning the microphone both near and far, I tried to make the measurements both in the control room which is not acoustically treated, and in the vocal booth which is treated.

 

[grignacarbo]

it seems that the problem depends on the audio interface, as you advised me, I connected the output directly to the input (without microphone) attached you can see the mdat file. So what does it mean? is my audio interface faulty?

 

[John Mulcahy]

That dip is centred at 8 kHz, so it looks more like the action of a tone control or some EQ. Make sure all the EQ is turned off and check that there is no monitoring, none of the mic signal should be routed to the output.