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Consider using an anechoic chamber from others. Every microphone and speaker manufacturer will have one, most Universities have huge EMI measurement chambers (working perfectly). They might let you use it for an hour at a time, or you can rent it for a day for some more money. If you need to build one by your self, start with a noise floor measurement box. ...


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speakers don't just emit sound towards the front, they emit sound in 360 degrees despite the efforts of designers. Higher frequency drivers are more directional than lower frequency drivers. The lower the frequency, the more 'omnidirectional' the device is. By attempting to measure frequency response vertically above a speaker, you are going to experience ...


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Based on a suggestion by Jojek in a comment, I tested the DC output using a sinusoidal signal of stepped amplitude: The results are given for 90dB SPL, 80dB SPL and 70dB SPL as read on the meter display. The plot also display the RMS value of the DC signal provided by the SLM. Barring measure error, the result matches the specifications of 33 mV/dB ...


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There is no formula you can use to make this conversion. It is unlikely your webcam would be suitable as a sound sensor due to the processing involved in detecting and multiplexing the audio into the visual data stream. Also, the 'dB' values you are quoting are meaningless. In order to be able to detect something useful, you would need a raw feed from the ...


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The key difference is calibration: a hand held sound meter, even a cheap one, has been calibrated in the factory. Your app and phone (microphone, internal preamp, dac) aren't. If you find a way to calibrate your app - most apps have a calibration setting - using a reference sound source or a calibrated SPL meter, you can improve the usefulness of those apps. ...


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There are pre-existing facilities that regularly measure the frequency response of microphones. you should call one of them (try pcb) and talk to them about your project... A chamber might not be the best way to measure this. But if you do want to build a chamber, a lot depends on what the lowest frequency you want to measure. If you have a quiet space, ...


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That's probably going to be tough to find. The only things I've spotted recently were articles discussing the loudest insects (which are some of the loudest creatures on the planet), and I could only say those were in the last year...specific articles, sources and dates are completely lost to me. That might be a place to restart your google search though. ...


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Unfortunately "small" and "anechoic" are mutually exclusive, at least at low frequencies. The length of the wedge absorbers needs to be at least a quarter of a wave length plus some extra space for the field dissipate. If you need to do less-echoic measurements, your best shot may be to find a large open space, get as far away from reflecting surfaces as ...


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