# Tag Info

## New answers tagged sound

1

The reason for the sqrt(2) in the definition of dBFS given by value_dBFS = 20*log10(rms(signal) * sqrt(2)) = 20*log10(rms(signal)) + 3.0103 is that this definition is explicitly designed such that the dBFS value of a full-scale sine wave equals 0. Since the RMS of the full-scale sine wave is 1/sqrt(2), multiplying rms(signal) by sqrt(2) ensures that the ...

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In a nutshell: yes, it does, at least under certain circumstances. In a noisy environment, people tend to not only increase their volume when speaking, but also speak in a higher pitch. It's called Lombard Effect, it's well known and you should find plenty of material about it.

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First of all, welcome to DSP SE. In general most (if not all) smartphones nowadays have some kind of noise cancellation technology integrated. The simplest of all is to have two microphones, one which is supposed to record the noise and the other one record the voice with the noise (please keep in mind that this is an oversimplification of the problem). Then ...

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is it ok to showcase this diagram ? Sorry, we can't tell you this. This is really a function of your specific application, the physics behind your signal, and how you exactly define "peak". DSP can offer you methods to suppress "near by" peaks or to de-noise multiple peaks but whether that's the right thing to do or not depends largely ...

0

As this post over at the apple stackexchange says, .aax files from Audible are indeed encrypted m4b files, which means that if I would decode an .aax file without converting it, I would get a .m4b file. This is possible with the following command: ffmpeg.exe -activation_bytes XXXXXX -i input.aax -c copy output.m4b The -c copy ensures that the data will not ...

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The maximum limit is probably like $20$ kHz because that’s the human top limit and there is no point in having a higher frequency speakers unless you want to use it as an animal repeller so in that case some manufacturers may chose to add a second special piezoelectric speaker (metal diaphragm) for ultrasounds. Don’t confuse the speaker frequency with the ...

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