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Is there an AudioUnit that can apply a fixed gain within an AudioGraph? Are there other alternative methods?

Jonathan Arbogast
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Unfortunately iOS only ships with 3 built-in AudioUnits that you can use, though it is possible to process raw sample data on the fly by setting up an AudioUnitRenderer. However, guessing from the name, you probably want to use the AU3DEmbeddedMixer AudioUnit if you are only interested in applying a quick gain reduction.

I'm not sure of the exact parameters required by this AU, but it shouldn't be too hard to figure out the header files.

Nik Reiman
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  • Thanks Nik. The downside to the 3DMixer is that is can't work with the native audio codec like the other AudioUnits can. My app has real-time audio processing constraints so I really wasn't thrilled about the idea of adding additional AudioConverters but maybe that's just what I'll have to do. – Jonathan Arbogast May 19 '11 at 13:45
  • @Jonathan Abrogast yeah, that is definitely a downside, but unfortunately iOS doesn't provide many processing units for you to use. But at least all you are doing in this case is applying gain, so at least the amount of work shouldn't be too much. :) – Nik Reiman May 19 '11 at 14:29