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For my senior design project, we're creating an acoustical test chamber that will measure the frequency and the sound pressure of the electrical device that is put in the chamber. The chamber won't be big, 1m X 1m X .5m at most. Also, we plan on measuring only the sounds that human ear can detect. My job is to select microphones, collect data and display it via MATLAB. I plan on using multiple sound cards as ADCs, so I will connect the microphones to the computer directly. We only have $200 budget for the whole project. I was wondering what types of microphones and sound cards (I might be able to get the sound cards from the school, but I'm not sure if they'll be good enough) I can use.

Thanks a lot!

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    Hire the microphone. You won't get anything like lab quality for 200 bucks. – Tetsujin Oct 16 '17 at 18:38
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Uh, you'll want measurement microphones. Those have omnidirectional response across all frequencies and a wide-range flat frequency response at the cost of mediocre signal-to-noise ratios. Which is not a problem since your test signal and/or your measurement period will be large enough to make the noise irrelevant. Measurement mics are not really useful for musical purposes, so any acquisition you take here will not be convertable to a different purpose.

On the plus side, the sound cards do not need to be particularly good. "multiple sound cards" however turns up all sort of warning bells since multiple sound cards cannot easily be synchronized unless they have facilities for that, and that usually means quite expensive external cards.

Any chance to just do multiple separate measurements?

An anechoic chamber of size 1m×1m×0.5m sounds like a hard challenge as well: at that size, modes with audible frequencies are almost impossible to avoid since it will be hard matching the walls' acoustic impedance well enough to that of the room to preclude standing waves in the audible range.

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