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getting data for SPL measurments
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getting data for SPL measurments


  • Subject: getting data for SPL measurments
  • From: Johan Eklund <email@hidden>
  • Date: Tue, 30 Mar 2010 14:03:18 +0200

Hello everyone.

I'm getting am thinking about developing a SPL measurement application in cocoa/core audio. I'm fairly new to mac programming in general, I've learnt some objC and made a few small apps in cocoa just for my own learning. I've looked thru the coreaudio documentation and it wasn't all that clear...

What i want to do it take the input from one channel of a core audio device, add a A, C or Z-weighting:
http://en.wikipedia.org/wiki/A-weighting#Calculation_of_some_common_weightings

After that i need to isolate a predefined number of samples (1s, 250ms or any other),  get the dBfs of them and make futher calulations with those numbers, including changing them according to an input calibration. I'm fairly familiar with the general methods as i work a sound engineer.

Now it's getting the input, applying the weighting and getting the sample info that i can't se how to to, do i need to learn more C or C++? I don't know much of either right now.
Maybe i'm in over my head but this seems like it should a simple project.

If anyone could tell me how you would go about a task like this (make a AU unit?)  and any further reading material it would be a great help.

Thanks
meck



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