PiSound for Frequency Analyzer


#1

Hi everyone! I’m new here and I need to know if the PiSound could be useful for my Project. I need to adquiere two audio signals from 2 different microphones for a certain frame of time and then do a FFT between both. For otherside i need to take out a pink noise and several kinds of signals to supply to a speaker. This instrument is call “Impedance Tube”.

I will appreciate any type of comment.

Thanks


#2

Hey, yes, FFT analysis can be done, we’ve used Jack/Alsa Audio Analyzer (JAAA) for real time monitoring of spectrum.

For connecting two microphones - Pisound has a stereo 6.35mm input, you’d have to split each channel separately, and the ‘gain’ control would be shared for both microphones, so in case you’d want to set different gain for each microphone individually it could be a bit poblematic. :slight_smile:


#3

Hi Giedrius, thanks for your response. I have one more doubt, in case that i want to use independent gains for each microphone, is it possible to use a pre amplification stage?, suppose with a OPA2134. But for that i need to know the maximums values that i can reach with the external gain considering that the internal gain will be set at 0dB (bypass) and manage the total gain externally. The other things is, the output of the preamp have to be differential or single-end? Thanks.


#4

The output should be single-ended, Pisound’s input and output ports are unbalanced.

As for amplification, you should amplify based on the sensitivity of your microphones, usually defined in their spec for example to something like ‘-40dB’, so in that case you should amplify it by up to 40dB, to reach ~0dB signal level. Adding a gain control for this would be ideal.


#5

Do you know if there is something similar as a terminal app?


#6

I’m not aware of any such terminal utility.