National Instrument offers several solutions for recording audio signals. You could use an E Series DAQ board to digitize the signal. These boards use a multiplexed input, so you should only choose this option if simultaneous sampling and phase information is not important to your analysis. It would also be a good idea to use some signal sonditioning on your signal to prevent aliasing. I would recommend a 16-bit board with a sampling rate of at least 100kHz. Here is an example board:
http://sine.ni.com/apps/we/nioc.vp?cid=10160〈=US
The best solution would be to use a board specifically designed for high precision audio measurements, such as the NI 4474. These boards offer 24-bit precision, simultaneous sampling, built in anti-aliasing filtering, and e
xcitation for sensors that require excitation. This would not require any additional signal condition. Here is the link:
http://sine.ni.com/apps/we/nioc.vp?cid=12058〈=US
Regards,
Brent R.
Applications Engineer
National Instruments