How to get AVAudioPlayer output to the speaker

I realize this question is fairly old but when I was struggling with the same problem I found a simple solution that hopefully will help anyone else looking to use the louder media speakers as opposed to the receiver speakers. The method I used was setting up the audio session with the DefaultToSpeaker option in AVAudioSessionCategoryOptions:

In Swift (assuming your audio session is named session) -

session.setCategory(AVAudioSessionCategoryPlayAndRecord, withOptions:AVAudioSessionCategoryOptions.DefaultToSpeaker, error: nil)

In Obj-C -

[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryPlayAndRecord withOptions:AVAudioSessionCategoryOptionDefaultToSpeaker error: nil];

Swift 3

Before recording the sound I set:

AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayAndRecord)

and before playback I set:

AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryAmbient)

Objective C

before recording:

[[AVAudioSession sharedInstance] setCategory: AVAudioSessionCategoryRecord error:nil];

before playback:

[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryAmbient error:nil];

From http://www.iphonedevsdk.com/forum/iphone-sdk-development-advanced-discussion/12890-audiosessionsetproperty-problem-playing-sound-listening-mic.html --

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