iPhone audio Filter

I am considering an app which takes sound (eventually an audio track) and applies an audio filter to it.

So I can play sounds with AudioServicesPlaySystemSound via AudioToolbox framework just fine.

What I need is a very simple example of how I might take a sound and apply (for instance) midrange boost etc. Actually the kind of alteration is irrelevant -- if I can get my head around how the alteration is done I can figure out the rest. I am just 开发者_运维百科finding both docs and examples of altering audio in code to be very scarce.

Thanks for any help!

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Unfortunately, anything beyond basic recording and playing of PCM data requires digging into the more murky depths of Core Audio. I would probably start by looking at the Core Audio Overview documentation from Apple. They provide an entire mechanism with Audio Units for writing a signal processor or "effect units" that sit in the audio processing graph.