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Sound frequency of recording with music module


#1

Hi all,

I’m trying to record a sound from the music module. I need high frequencies (~15-20 kHz) and ideally a lossless format.

When I record however I get an ogg file sampled at 16 kHz (and therefore with sound up to 8 kHz), which is actually quite sharply cut just over 2 kHz, as per the 2 images attached. What is the cause of this? I initially thought it was the microphone I was using, but actually plugging in the lineout of my computer playing a frequency sweep yields the same results.

These are my hypothesis:

  • The music module has a filter at ~2 kHz
  • The ogg encoding on the music module discards everything over 2 kHz
  • The motherboard (FEZ Spider) is not fast enough to sample at more than 2 kHz or it’s busy doing something else.

Could anyone point me in the right direction?

Also:

  • is it possible to sample at >16 kHz with the music module (44.1 for example)?
  • is it possible to save in wav instead of ogg vorbis?

My alternative solution would be to bypass the music module, attach the microphone to an analogue port, save the samples and encode them into a wav file. Not sure how difficult that would be though.

Thanks,
Davide