I have a USB scarlet solo A/D. The mic input has a level control. I put the mic in the calibrator and adjust the level control until REW reads 94 db SPL, not using a cal file. The calibrator also has 114 and 124 levels via a selector switch, so, I can check that those follow. They usually do...
So now I know the mic and signal chain is reading SPL to a reference value. This gets me better than a relative measurement; where the y axis is meaningless except as to gauge variation in a FR plot. The assumption is the mic and scarlet interface is flat to all other frequencies, as the calibrator outputs 1 kHz I think.
When I was employed, we had the B&K pistonphones on hand and could do the same thing, so the analyzer would know what signal was what db SPL. Since the mics and analyzer were always in cal, we rarely used the pistonphones - but we had 'em in case of a challenge.
So now I know the mic and signal chain is reading SPL to a reference value. This gets me better than a relative measurement; where the y axis is meaningless except as to gauge variation in a FR plot. The assumption is the mic and scarlet interface is flat to all other frequencies, as the calibrator outputs 1 kHz I think.
When I was employed, we had the B&K pistonphones on hand and could do the same thing, so the analyzer would know what signal was what db SPL. Since the mics and analyzer were always in cal, we rarely used the pistonphones - but we had 'em in case of a challenge.
Thanks jj. There is a Genrad on Ebay, I may buy it. When I worked for Marantz, I had one in my desk drawer.
I bought a Umik-1! ( Sent my 7012 for cal. Takes 2 weeks b4 I get it back).
I made my first measurement with REW with Umik-1.
Question:
My Klipschorn sensitivity is 105 dB/w/m. Why REW FR measurement shows sensitivity around 80 dB?
Also JBL L200 sensitivity is 95 dB/W/m, yet the REW FR graph shows the same 80 dB.
I get this error message when I try to import the previously measured FR in REW: mdat.txt not found.
Art
I made my first measurement with REW with Umik-1.
Question:
My Klipschorn sensitivity is 105 dB/w/m. Why REW FR measurement shows sensitivity around 80 dB?
Also JBL L200 sensitivity is 95 dB/W/m, yet the REW FR graph shows the same 80 dB.
I get this error message when I try to import the previously measured FR in REW: mdat.txt not found.
Art
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Get your calibrator yet? That's one way to clear up the discrepancy. I mean it's a brand new USB mic - should be right, right?
Note what’s stated at #5 below:
https://www.minidsp.com/applications/acoustic-measurements/umik-1-setup-with-rew
https://www.minidsp.com/applications/acoustic-measurements/umik-1-setup-with-rew