trouble getting started

Hi there, I decided to dip my toe into the world of REW. Scary stuff! The very first problem I encounter is at the point where we're supposed to adjust the mic level. I'm using the UMIK-1 usb mic. I have it plugged into my Dell pc and Windows 7 is definitely recognizing it. I can go into Control Panel -> Sound -> Recording Tab and see the mic. When I click on the Properties button, the Microphone Properties dialog box opens. It has a Levels tab. I select that. The adjustment slider is up all the way so I can't move it up any further. When doing the REW levels test they require me to up the input level of the mic to match -12db of the Output level, but I can't. I don't know of any other way to adjust the mic level. Please advise.

Alan

That's not required for USB mics, as clearly stated in the help.

You need to adjust the signal output level in REW or your amp to reach the recommended -12 dB.

Kind of related to this thread, so not starting a new one.
I'm needing to match the out/out levels of an Earthworks M30 mic on an iRigPro USB interface. Presumably I simply set the (M-Audio Transit USB) output to 12dB and use the gain control on the iRigPro to match. But at what sort of acoustic audio level in the room ?

There's no acoustic output for a soundcard calibration, just a loopback cable. To set levels for the mic you can use any convenient acoustic level and adjust gain to ensure the dBFS input level leaves enough headroom for the highest level you want to measure.