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Confused with setting gain level on mic ECM8000

3K views 2 replies 2 participants last post by  donktard 
#1 ·
Hello.
I have ECM8000 Behringer microphone which is connected to USB soundcard. So, when trying to measure a room, I am stuck at a point where I need to calibrate microphone.
REW guide says that if I have a calibration file with sensitivity parameters I can skip this step. However, although I do have calibration file, the issue is that my soundcard has a gain knob on each of its inputs. Therefore I assume I still need to calibrate.
So, I turn on my handheld SPL meter.
I open SPL meter in REW.
I click Calibrate and use speaker signal.
I increase volume until my handheld SPL meter says 90db.
Then I type in 90 in SPL Reading Calibration message box.
So here is the confusing part...
below big db(C) S red numbers on top of SPL meter is a dB FS gauge that measures microphone level.
And on my usb soundcard i can use knob to increase gain, there is also LED lights that tell me if gain is too much and signal is clipping.
So, should I simply increase gain somewhat below clipping and ignore whatever is going on on that dB FS gauge? Or is there something else I should do?

Thank you.
 
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#2 ·
Hello.
I have ECM8000 Behringer microphone which is connected to USB soundcard. So, when trying to measure a room, I am stuck at a point where I need to calibrate microphone.
REW guide says that if I have a calibration file with sensitivity parameters I can skip this step. However, although I do have calibration file...
Perhaps a bit of confusion here, the mic calibration that includes sensitivity parameters only comes with USB mics, not the type you have.

...the issue is that my soundcard has a gain knob on each of its inputs. Therefore I assume I still need to calibrate.
The gain knobs on the sound card have nothing to do with the mic calibration file. Calibrating the mic is not something the user does himself. If you have a calibration file, all you need to do is load it into REW, via Preferences -> Mic/Meter tab.

The gain knobs on the sound card are for setting input levels for the sound card.


So, I turn on my handheld SPL meter.
I open SPL meter in REW.
I click Calibrate and use speaker signal.
I increase volume until my handheld SPL meter says 90db.
Then I type in 90 in SPL Reading Calibration message box.
Unless you have a particular reason for doing so, there is no reason to calibrate the SPL meter at 90 dB. The 75 dB level typically recommended is perfectly fine. The SPL meter calibration is merely to give REW a point of reference. IOW, you’re “telling” REW (and by default the meter itself) where 75 dB “is.” At that point it can track and accurately display any sound pressure level.


So here is the confusing part...
below big db(C) S red numbers on top of SPL meter is a dB FS gauge that measures microphone level.
And on my usb soundcard i can use knob to increase gain, there is also LED lights that tell me if gain is too much and signal is clipping.
So, should I simply increase gain somewhat below clipping and ignore whatever is going on on that dB FS gauge? Or is there something else I should do?
I haven’t used REW since the FS gauge was added as a feature, but according to the Help Files it mirrors the same Input level that’s shown in the Preferences -> Soundcard window. So, it’s nothing to worry about. Just go ahead and calibrate your input levels as directed in the Soundcard widow, and keep both the soundcard itself and the REW meters below clipping. :T

Regards,
Wayne
 
#3 ·
Perhaps a bit of confusion here, the mic calibration that includes sensitivity parameters only comes with USB mics, not the type you have.

The gain knobs on the sound card have nothing to do with the mic calibration file. Calibrating the mic is not something the user does himself. If you have a calibration file, all you need to do is load it into REW, via Preferences -> Mic/Meter tab.

The gain knobs on the sound card are for setting input levels for the sound card.
Yes, I understand that SPL meter calibration is used only to calibrate SPL level, not the actual response of the microphone. I just expressed myself poorly :D

Unless you have a particular reason for doing so, there is no reason to calibrate the SPL meter at 90 dB. The 75 dB level typically recommended is perfectly fine. The SPL meter calibration is merely to give REW a point of reference. IOW, you’re “telling” REW (and by default the meter itself) where 75 dB “is.” At that point it can track and accurately display any sound pressure level.

I haven’t used REW since the FS gauge was added as a feature, but according to the Help Files it mirrors the same Input level that’s shown in the Preferences -> Soundcard window. So, it’s nothing to worry about. Just go ahead and calibrate your input levels as directed in the Soundcard widow, and keep both the soundcard itself and the REW meters below clipping. :T

Regards,
Wayne
I calibrated at 90 (or 85, 80, doesnt matter) because I didn't really understand how all of it worked. But I think I figured it out today and that basically while I calibrate SPL meter I should also adjust gain on microphone properly and once that is done I shouldn't adjust mic gain afterwards because it will mess with my results (like it did).

Thanks for the response.
 
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