Oscillating SPL curve on soundcard calibtation

[Matt Carlisle]

Does anyone know why I am getting this kind of a curve form calibrating the sound card? I using a Presonus Firewirestudio 2626 with Windows 10 pro 64 bit (Presonus drivers installed in Win 7 legacy mode)

 

[John Mulcahy]

The input is being mixed back to the output. The only thing that gets to the output should be the signal from REW.

 

[Matt Carlisle]

Thank you, When I do not raise input and output levels at soundcard I am unable to get signal on IN meter above -35db

 

[John Mulcahy]

The issue is with the mixer settings (monitoring) rather than the level. Your mixer is set up to direct some of the input signal back to the output. You have to disable that. There must be no input signal getting to the output.

 

[Matt Carlisle]

Thanks again, I found the problem, there is a checkbox in the interface mixer software that was checked to allow direct monitoring. I unchecked it and now I get this

 

[John Mulcahy]

Looks good.