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Hi, I was wondering if I still need to apply the Radioshack offset/calibration numbers for my SPL if I go through the REW calibrations? In other words, do I have to offset the results from REW to account for the known inaccuracy of the Radioshack SPL?

Thank you
 

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Hi tooobie...

The REW calibration file is a great deal more acurate than the offset calibration numbers floating around out there. The answer to your question is no, you don't need to apply the additional correction factors. Just make sure you are using the *new* calibration file (for whichever Rat Shack meter you have), and not the old one...
 
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please excuse this lame question but where is the new calibration file and how do i make sure REW uses it?
 

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Go to the downloads page for the current version of REW, and there are links for several different calibration files. Just select the one you have. Then in REW, go to the 'Meter' menu on the tool bar, select 'Load Meter/Microphone Calibration File', and point it at the file you just downloaded. Now, it will be automatically loaded next time you start REW.... Have fun!
 

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Is it not a good idea to use the RS Meter, REQW combination for seeing how your room acoustics are like for the speakers? If its alright, are there any calibration files for frequencies greater than 2khz? The cal file only gets to around 110hz I believe.

Thanks!
 

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are there any calibration files for frequencies greater than 2khz? The cal file only gets to around 110hz I believe
It only goes to 110Hz because that's where the accuracy of the RS meter becomes close enough to use the standard C-Weighting that REW applies. C-Weight is applied by REW in all areas outside the frequency limits of any supplied calibration file.

Anything above 10KHz is not recommended for the RS meter.

Generally for a subwoofer we're only concerned about equalizing from 10Hz to 200Hz area.

brucek
 

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Thanks for your reply! I was using the software to get a whole room response so I could see how badly the reflections were playing onto the source. Unfortunately, without a full specturm calibration, I cannot see for sure what the rest of the spectrum really looks like.
 

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Jonathan,

The general shape of the RS meter response in shown in a small graph in the manual that comes with the meter, but there will be too much variability between meters to get reliable full range measurements that could be used to decide whether your room has appropriate levels of absorption at high frequencies. You will be able to see the influence of reflections, however, particularly in the impulse response.

For full range measurement you need a measurement microphone such as Behringer's ECM8000 or the mic/preamp sets IBF Acoustics offer (see the MP-1r kit at http://www.ibf-acoustic.com/2005/index05.html). If you search in this forum you will find info on using the ECM8000, note that it needs a preamp.
 

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The Behringer's EMC8000 should be sent off for testing and and development of its own unique calibration file.
 

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Here's a link to more info on having the ECM8000 calibrated.

You could use my calibration file, but there's no guarantee it will be exact for the next one, although the calibrationist/er states they all seem to be about the same out of the box.
 
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