acoustic measurements in a noisy environment
acoustic measurements in a noisy environment
(OP)
I'm faily new to acoustics and was wondering whether I can take legible reading/gain a accurate signal in a fairly noisy environment. If I can identify the frequency that I'm looking for can filters be used to reduce eliminate unwanted noise sufficiently?





RE: acoustic measurements in a noisy environment
If the frequency of interest is a pure tone (sine wave), then you do FFT frequency analysis with a narrow filter (lots of line of resolution) and use spectrum averaging to make the tone standout with random background sound being averaged to a low level. Other tricks include:
1) Get closer to the source
2) Wait for change (or turn off) background sound
3) Use a directional microphone
4) Use a pressure gradient microphone or intensity probe
Walt
RE: acoustic measurements in a noisy environment
This is not a very common technique, admittedly.
If you describe more exactly what you are trying to do we can be more helpful, possibly.
Cheers
Greg Locock
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RE: acoustic measurements in a noisy environment
In order for it to work, you need a good idea of the position of the noise source.
And another technique useful for measurements in noisy environments is order tracking, when you have a tachometer or speed signal related to the noise source. You filter out non-synchronous noise.
- R
RE: acoustic measurements in a noisy environment
RE: acoustic measurements in a noisy environment
That's why the particle velocity transducer (i.e., flowmeter) is so cool - you get to skip a step. or you get to measure intensity "directly."