Calibrate the soundcard (not applicable when using a USB microphone)

[RuneW]

Why is this? Isn't the soundcard calibration needed to make the output linear? I don't get it.

I'm going to use a miniDSP UMIK-1 (which is a USB microphone).

 

[John Mulcahy]

Soundcard calibration serves two purposes:

• It checks for monitoring being active when input and output are on the same device, monitoring needs to be disabled
• It allows the low and high frequency roll-offs of the soundcard to be compensated for. That tends to be more of a problem on the input than the output, and at low frequencies than high, due to coupling capacitors on the inputs. It is very rare nowadays to find soundcards that aren't flat over the 20 Hz to 20 kHz span, however.

When a USB mic is being used its response characteristics are already compensated for in its calibration file. The soundcard's contribution only affects the output, and it is rare to have response issues there unless the output is driving a very low impedance input which would be very unusual. There is no way to distinguish the input and output contributions of a loopback measurement so the effect of the output can't be determined anyway, making it meaningless to perform any kind of loopback measurement.

 

[RuneW]

Soundcard calibration serves two purposes:

• It checks for monitoring being active when input and output are on the same device, monitoring needs to be disabled
• It allows the low and high frequency roll-offs of the soundcard to be compensated for. That tends to be more of a problem on the input than the output, and at low frequencies than high, due to coupling capacitors on the inputs. It is very rare nowadays to find soundcards that aren't flat over the 20 Hz to 20 kHz span, however.

Thanks for the explanation!