Sound card calibration
Steps to calibrate your sound device
- Be sure to have configured DRC123.
- Disable all other filter plug-ins, especially equalizers.
- If you are an expert you might also have a look at the extended
calibration options page.
Method 1 - fast
- Connect line in of your sound
card to
line out.
- Select mode Stereo loopback (default).
- Press Run button.
- Adjust the volume to get a reasonable recording level.
Note that volume changes discard the result.
- Wait until the results are reasonable smooth.
- Press Abort/Stop button.
- Enter a description to identify your sound device
(optional).
- Enter a file name - without extension.
- Press Save button to save the result.
It is not required that the response is approximately at 0 dB as
long as the result is smooth.
Method 2 - slower, more accurate
- Connect left line in of your sound card to
left line out and right line in to ground.
- Select mode Left channel only.
- Press Run button.
- Adjust the volume to get a reasonable recording level.
Note that volume changes discard the result.
- Wait until the results are reasonable smooth.
- Press Abort/Stop button.
- Connect right line in of your
sound card to
right line out and left line in to ground.
- Select mode Right channel only.
- Press Run button.
- Do not change the volume after step 4. otherwise the results will
no longer match.
- Wait until the results are reasonable smooth.
- Press Abort/Stop button.
- Connect left and right line in
of your
sound card to
left line out.
- Select mode Left to both channels.
- Press Run button.
- Wait until the results are reasonable smooth.
- Press Abort/Stop button.
- Enter a description to identify your sound device
(optional).
- Enter a file name - without extension.
- Press Save button to save the result.
Troubleshooting
Input
overdrive
If you do not get
reasonable results in step 5, especially if the
green and pink graph in the frequency response are noisy and graphs on
the right show high and irregular values, then it is likely that
you overdrive your line input.
Reduce the volume and repeat from step 5.
Equalizer
enabled
If the frequency response is irregular but well reproducible (does
not
change with longer measurements) then most likely you have REALEQ or
some other equalizer plug-in still enabled.
Disable all equalizers and other sound enhancement plug-ins except
for DCR123 unless you want DRC123 to compensate for the
effect of them. ;-)
Different
Sound
device
If the response decreases at higher frequencies with measurement
time then you used another sound card for playback and recording. This
causes the the frequencies of the test signal to be slightly shifted
because of tolerances of the crystal oscillators of the sound devices.
DRC123 is not designed to work with frequency shifts because this
would significantly decrease the accuracy of the results. DRC123 relies
on several symmetries of the setup to get high precision results from
cheap, uncalibrated hardware. The exact frequency is one of them. So it
is essential to use the same device for recording and
playback. This also implies that USB measurement microphones
are
unusable (i.e. Behringer ECM 8000) because they cannot support a
synchronous playback
channel.