No. Noise floor has nothing to do with frequency response. What we were discussing was that some early batches had elevated noise floor issues that have now been fixed. It shouldn't matter to you unless you're doing special measurements that are affected by noise floor, like harmonic distortion measurements.Sorry I did not read the whole thread but does that mean one does not have to get the UMIK calibrated?
AFAIK the UMIK-1 volume control is purely digital, so it doesn't really matter what measurement level you end up with, as it makes no difference with respect to noise floor. -25dB in normal measurement conditions with the UMIK-1 seems normal to me considering the max SPL of the mic. Just ignore REW's warnings about measurement level, they don't really make sense when using a fixed-gain mic.I've calibrated the SPL meter in REW with an external SPL meter and all looked well but when I go to perform tests it seems my system needs to be much too loud to get -25 db input to REW. I've tried the set levels but my input from the UMIK seems much too low for the volume my speakers are putting out. When I get it loud enough at my listening position to satisfy REW's -25db input my system distorts badly from the wave that REW generates. I have a rather loud system that shouldn't have any problem hitting 75 db at the listening position.
I would strongly advise against that, as laptop analog outputs are among the worst imaginable.From the little bit of reading I've done in this thread I take it I should mention that I'm using the analog out of my laptop.
Use the V5.01 beta version of REW from here, it will automatically recognise your mic and prompt you for the calibration file. USB mics operate at lower signal levels (to give them headroom for loud sounds), -25 dB is not required.I recently purchased a UMIK-1 and can't seem to get it going.
So, from reading the forum posts Cross-Spectrum will not test for sensitivity (I am waiting on my umik-1 to arrive). However, if I download the minidsp calibration tied to my serial # and cut-n-paste the sensitivity line from it to the one provided by CS, then the umik-1 will act as an SPL meter correct?
Shouldn't matter, REW compensates for the Windows volume setting, but make sure you use REW V5.01 beta.I'm not sure if this has been asked before, but should the mic level in control panel (Windows7) be set to +12dB? I have done some RTA noise measurements and I got the impression that the SPL was wrong?
CorrectI guess when using the UMIK-1 one should not use any calibration file for the input sound card, only the mic calibration?
No, that is to produce plots that are more easily compared with sweeps. Just read the SPL figure as shown top right, but bear in mind it is unweighted, or read the figure on REW's SPL meter with whatever weighting you select.Finally should I use "adjust RTA levels" when measuring background noise?