# SPL Calibration Files



## bayrowser (Sep 28, 2012)

Hi,
2 questions around SPL calibration methodology

1. Using Generic Calibration Files
I finally got past the calibration of the Behringer UCA222 soundcard and onto the SPL calibration. I notice the availability of generic calibration files for my RS 33-4050 in the Downloads section which is great.

Question is how do I import this .cal file into the SPL calibration files of REW?

Initially I could not even open the files but finally managed with Windows Notepad which displayed the correction values. What do I do next....

2. SPL Calibration Procedure
When I open the REW SPL meter and press 'calibrate' to generate a pink noise through my speakers - its pretty faint (<70dB) so I increased the sound levels via the volume control of my AVR. Is this legitimate?? as I then input/adjusted the SPL reading of the REW SPL meter - doesnt seem right. 
Should I increase the input volume of my soundcard via the soundcard settings so that the pink noise generation is higher and registered within 80db on the RS SPL?
Thanks for enlightenment!
rgds
BR


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## Wayne A. Pflughaupt (Apr 13, 2006)

bayrowser said:


> I notice the availability of generic calibration files for my RS 33-4050 in the Downloads section which is great.
> 
> Question is how do I import this .cal file into the SPL calibration files of REW?


If you’re only using the meter for the SPL calibration, you don’t need the file. It is file only needed if you plan to use the meter as your measurement mic. Just save the calibration file to your computer in your REW folder. From there you can load it into the program.




> When I open the REW SPL meter and press 'calibrate' to generate a pink noise through my speakers - its pretty faint (<70dB) so I increased the sound levels via the volume control of my AVR. Is this legitimate?? as I then input/adjusted the SPL reading of the REW SPL meter - doesnt seem right.


Yes, that is correct: Increase your AVR’s volume control until your meter reads 75 dB. Then enter that figure into REW’s meter. Now the program “knows” what 75 dB is and can then calculate and show any other sound level readings as well.

Regards, 
Wayne


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## bayrowser (Sep 28, 2012)

Wayne,
Thanks for that really quick response. Much appreciated.

I do plan to use the RS meter as the measurement mic and so was looking to download the .cal file. My issue is that when I download the file ( using Windows 7), I cant seem to open it except using Notepad when it then displays values in notepad.
Do I then copy this notepad file into the REW folder? I thought the REW folder should have a .cal file.

I just cant seem to download this .cal file into the REW folder. Tried to look for some programs without success.

Will keep trying.

Cheers
suresh


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## jtalden (Mar 12, 2009)

Download and locate the file wherever you want on your PC.
Then open the "Preferences-Mic/Meter" window in REW as shown below and select "Browse".
Then find the and open the .cal file you saved.
Once that is done the cal file will show up in the "File" field and it will then be applied to all future measurements in REW until you change it.


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## bayrowser (Sep 28, 2012)

Thanks for that detailed explanation. I just could never get the .cal file to download - anyway i think its done. Used the Browse function you pointed out, to pick it up from the Downloads folder! 
I have since done a number of measurements and now comes the hard part - to make sense of all those lovely charts!
It will be many hours poring over others experiences and trying to figure this out - may have to come back again! cheers


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## Wayne A. Pflughaupt (Apr 13, 2006)

bayrowser said:


> may have to come back again!


No problem, we’ll be here! :T

Perhaps John can correct me if I’m wrong, but I believe you’ll need to select the “C Weighted Meter” option, not Z-rated as shown in the screenshot.

Regards, 
Wayne


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## jtalden (Mar 12, 2009)

bayrowser said:


> Thanks for that detailed explanation. I just could never get the .cal file to download - anyway i think its done. Used the Browse function you pointed out, to pick it up from the Downloads folder!
> I have since done a number of measurements and now comes the hard part - to make sense of all those lovely charts!
> It will be many hours poring over others experiences and trying to figure this out - may have to come back again! cheers


You should be able to just copy and paste the .cal file from the download folder to your REW folder or wherever you like using Windows Explorer? Then again, maybe I still don't understand your problem.


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## jtalden (Mar 12, 2009)

Wayne A. Pflughaupt said:


> ...
> 
> Perhaps John can correct me if I’m wrong, but I believe you’ll need to select the “C Weighted Meter” option, not Z-rated as shown in the screenshot.
> 
> ...


Thanks!
Yes, I think you are correct. “C Weighted SPL Meter” should always be selected when using a C weighted SLM (with or without a .cal file).


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## Wayne A. Pflughaupt (Apr 13, 2006)

bayrowser said:


> I just could never get the .cal file to download - anyway i think its done. Used the Browse function you pointed out, to pick it up from the Downloads folder!


Right, Windows 7 downloads everything to that specific folder. From there you can cut and paste it to your REW folder with the other files, but either way it looks like you got it loaded into REW okay.

Regards, 
Wayne


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## bayrowser (Sep 28, 2012)

THANK YOU GUYS!!
Fantastic to have this level of support and responsiveness.
Need to visit the Donations Section:innocent:

cheers
BR


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## Djoko (Nov 14, 2013)

Wayne A. Pflughaupt said:


> If you’re only using the meter for the SPL calibration, you don’t need the file.


Wayne, if you can explain in more detail how to use the SPL meter with REW V5 and how to use the microphone?



Wayne A. Pflughaupt said:


> Yes, that is correct: Increase your AVR’s volume control until your meter reads 75 dB. Then enter that figure into REW’s meter. Now the program “knows” what 75 dB is and can then calculate and show any other sound level readings as well.


How microphone must be away from the speakers during measurement and the place?
Do you perhaps midway between the two speakers?

Sorry to many questions at once, but I'm new at this, so I ask all of you do not understand.
greeting


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## JohnM (Apr 11, 2006)

Djoko said:


> Wayne, if you can explain in more detail how to use the SPL meter with REW V5 and how to use the microphone?


You can find information about getting REW set up in this thread and of course in the REW help files.



> How microphone must be away from the speakers during measurement and the place?
> Do you perhaps midway between the two speakers?


The mic would normally be placed where your head is when you listen.

For general questions on using REW it is best to post in the main REW forum.


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## Djoko (Nov 14, 2013)

thanks a lot


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