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Date: Sat, 05 May 2012 12:00:13 +0200
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To: geda-user AT delorie DOT com
Subject: Re: [geda-user] Frequency spectrum of a duck quack
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On 05/05/12 11:12, Alexis Phoenix wrote:
> Record a duck quacking and play it back to a spectrum analyser (I
> think that's what it's called)... Or save it as a midi sound file
> might be an option. Actually thinking about it, I'll bet you can get
> frequency analysis software now.
>
> On 5 May 2012 04:45, Rob Butts<r DOT butts2 AT gmail DOT com>  wrote:
>> Does anyone have an idea of how I would get the frequency spectrum of a duck
>> quack? Ideally I would like to reproduce the sound in a micro and send it to
>> a speaker.
>>
>> Thoughts? Suggestions? Ideas?
>>
>>   Thanks!
>
AFAIK MIDI isn't suitable for that.

I'd say the best way to go about it depends on the quality you're 
looking for. If you're not looking for Ultra Super Mega HD™ quality, 
record it as a simple WAV file (or find a public domain WAV on the 
internet) and use software to analyse the spectrum. Audacity 
(http://audacity.sourceforge.net/) can do that.

If you /are/ looking for Ultra Super Mega HD™ quality, it's probably 
best to pay a professional sound technician to record some ducks and 
plot the spectrum for you -- for a one-off spectrum analysis, that's 
bound to be a whole lot cheaper than getting the equipment and training 
needed to do it yourself.

It's probably easier to just play a recording than to reproduce the 
sound yourself, though. Audacity should be able to convert a sound file 
to raw PCM samples that you can just pipe into a DAC at a fixed rate. 
All that's left then is storing the file; if it's too large to fit on a 
microcontroller's EEPROM or program memory, it shouldn't be too hard to 
find an SPI/I²C memory chip of sufficient size. Or you could store it in 
a compressed format and decompress it in firmware; I'd imagine that's 
/still/ easier than reproducing the sound from the frequency spectrum.


Peter