# USB Mic SPL Calibration



## Phillips (Aug 12, 2011)

Hi i have a Onmimic V1 that i use currently with REW. 

It has a "Sens Factor =-4.083dB but the SPL seems to be approx. 18db too hot.

In the Omnimic software it appears to be ok.

Does REW calculate it different?

Thanks in advance


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## JohnM (Apr 11, 2006)

Which OS are you using?
What is the input volume setting?
Can you provide some example data when playing (say) a speaker cal signal, stating the REW SPL meter SPL value and dB FS value (just below the A/C/Z selector buttons), the input volume setting and the SPL figure the Omnimic reports?


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## Phillips (Aug 12, 2011)

JohnM said:


> Which OS are you using?
> What is the input volume setting?
> Can you provide some example data when playing (say) a speaker cal signal, stating the REW SPL meter SPL value and dB FS value (just below the A/C/Z selector buttons), the input volume setting and the SPL figure the Omnimic reports?


Hi John i have attached screen shots.

The Omnimic software was showing 70dbspl c curve slow

Interesting when i disconnected then connected again i got what is on page 2 (no alterations to volume etc).

Thanks

View attachment SPL Calibration.pdf


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## Phillips (Aug 12, 2011)

I see that similiar things are happening with the UMIK.


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## Phillips (Aug 12, 2011)

JohnM said:


> Which OS are you using?
> What is the input volume setting?
> Can you provide some example data when playing (say) a speaker cal signal, stating the REW SPL meter SPL value and dB FS value (just below the A/C/Z selector buttons), the input volume setting and the SPL figure the Omnimic reports?



Hi John is there any progress on this?

Thanks in advance


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## JohnM (Apr 11, 2006)

I have made some changes for the next beta, but it is difficult to come up with a definite action for that mic when you have posted results that differ by 30 dB but say they were for identical settings.


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## Phillips (Aug 12, 2011)

JohnM said:


> I have made some changes for the next beta, but it is difficult to come up with a definite action for that mic when you have posted results that differ by 30 dB but say they were for identical settings.



I changed the "Sens Factor =-4.083db" to "Sens Factor =15.083db" and this seem to bring it up with what the Omnimic software was showing.

Hope this is a bit clearer


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