AVAudioRecorder normalize volume

I've got an app that records audio.开发者_运维问答 I'm wondering how I can increase the gain. is there a way to normalize the audio or amplify it somehow?

thanks, howie

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Looks like I found a solution. According to the documentation the AVAudioPlayer volume can be between 0.0 and 1.0. Apparently it can be set to a value greater than 1.0. By increasing the volume I was able to achieve the same desired result. While it's not normalized, the gain is increased.

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#import <AudioToolbox/AudioServices.h>

UInt32 audioRouteOverride = kAudioSessionOverrideAudioRoute_Speaker;                
AudioSessionSetProperty (kAudioSessionProperty_OverrideAudioRoute,          
                             sizeof (audioRouteOverride),&audioRouteOverride);  

It will play your sound in Speaker mode.