Re: Generating variable frequency tones
Re: Generating variable frequency tones
- Subject: Re: Generating variable frequency tones
- From: Kyle Sluder <email@hidden>
- Date: Fri, 10 Sep 2010 02:24:05 -0700
On Sep 10, 2010, at 1:19 AM, vincent habchi <email@hidden> wrote:
> Le 9 sept. 2010 à 21:58, Remco Poelstra a écrit :
>
>> I'm looking for some way to generate a tone that resembles the sound of an instrument. I need precise control of the base frequency (pitch). I'm wondering what would be the best way to generate it on an iPhone.
>> Store a file with a know frequency and resample it to the desired frequency? Synthesize a tone by calculating a bunch of sines? Doing some FFT trick on a file?
>> If someone can give some insight into what would best fit the H/W available it would be grateful.
>
> Basically, that's not really a Cocoa related question. If you want to generate a sine wave with a very precise frequency, try to dig into the fairly simple DDS theory. That's the way HF generators achieve sub-hertz step precision at 100 MHz or above. Very easy to replicate on an iPhone.
Also read through the archives of the coreaudio-api list. Lots of information about your specific case there.
--Kyle Sluder_______________________________________________
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