george seifert Posted November 13, 2008 Report Share Posted November 13, 2008 Slightly off topic I suppose, but somebody here must know this. I have a Bruel & Kjaer (2250) sound level meter. I want to convert the raw data signal from it to dB(A). The company wasn't much help. It has an option to A weight the input signal (from the built in microphone). I can get a waveform from the device and am converting it with a DAQ card, but have no idea how to convert to dB(A). Unfortunately I don't have the Sound and Vibration toolkit. Can anybody help with the conversion or suggest a place to look? Thanks, George Quote Link to comment
Francois Normandin Posted November 13, 2008 Report Share Posted November 13, 2008 QUOTE (george seifert @ Nov 12 2008, 04:47 PM) Slightly off topic I suppose, but somebody here must know this. I have a Bruel & Kjaer (2250) sound level meter. I want to convert the raw data signal from it to dB(A). The company wasn't much help. It has an option to A weight the input signal (from the built in microphone). I can get a waveform from the device and am converting it with a DAQ card, but have no idea how to convert to dB(A). Unfortunately I don't have the Sound and Vibration toolkit. Can anybody help with the conversion or suggest a place to look?Thanks, George Hi George, I'm not familiar with this device, but what are the output signal units? It is usual to have dB/V. From the datasheet, I think it would be 0.02dB per volt. (0V = 0dB and 4V = 200 dB.) If the signal is not A-weighed already, this wikipedia page gives a calculation method for http://en.wikipedia.org/wiki/A-weighting' rel='nofollow' target="_blank">A-weighing. Quote Link to comment
Anders Björk Posted November 14, 2008 Report Share Posted November 14, 2008 QUOTE (normandinf @ Nov 13 2008, 12:58 AM) Hi George, I'm not familiar with this device, but what are the output signal units? It is usual to have dB/V. From the datasheet, I think it would be 0.02dB per volt. (0V = 0dB and 4V = 200 dB.) If the signal is not A-weighed already, this wikipedia page gives a calculation method for http://en.wikipedia.org/wiki/A-weighting' rel='nofollow' target="_blank">A-weighing. Well for microphones you have one base amplitude and accelerometers on other. So log of a ratio Ayour/Abase. Look it up on wikipedia or some other place. For the A-weighting part there are a formula for that on wikipedia as well if I remember correctly. Quote Link to comment
george seifert Posted November 14, 2008 Author Report Share Posted November 14, 2008 Thanks guys. I didn't even consider Wikipedia for this problem. George Quote Link to comment
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