Sound issues on an iPhone app.

[zaxonus]

I have the following issue in an iPhone app.

The sound almost works, but with some restrictions. More precisely, here is what happens:

If I use an earphone connected to my the iPod touch trough a TRS connector I cannot hear anything.
If I use an earphone connected to my the iPod touch trough a TRRS connector I can hear without any problem.
(I have checked using the apple original Music app, that my connectors are working well)

See here for what is a TRS or TRRS connector : http://en.wikipedia.org/wiki/File:IPod_and_iPhone_audio_plugs.JPG

The iPod touch I use is as this:
Model: PB533J
iOS version:4.2.1 (8C148)

When I run the same application on an iPad. The sound is only coming out through the speakers and not through the earphone, whatever connector I use.
(Here also I have checked using the apple original Music app, that my connectors are working well)
The iPad I use is as this:
Model: MB294J
iOS version:5.5.1 (9B206)

Has anyone an idea of what might be the problem? Thanks for any bit of information.

 

[falterego]

I'm not too familiar with what channels run on what portion of the TRS and TRRS connectors, but it seems like the two rings are what pickup the signal for audio to come through on your headphones/speakers.

Try turning on mono audio in settings > general > accessibility and see if sound works on the TRS connector. If it works, then the app is only directing audio one one channel (whichever the second ring on the TRRS connector is for), and on the TRS connector that section is simply the sleeve which I believe is null and doesn't transmit/receive audio.

 

[zaxonus]

Thanks for the reply.

The Accessibility option only appears on my iPad and not on my iPhone touch.

I tried to change it on the iPad, but it did not make any difference.

I also tried to change AVNumberOfChannelsKey from 1 to 2 in the sound settings (in my app), but again it did not make any difference.

I remember that when I started to use the sound in this app, I could hear only from one side of the earphone and I had to modify this(AVNumberOfChannelsKey) to solve the problem.

Anyway, it seems like I have a number of details in front of me to fix.

Since the app should work, transparently for the user, with both TRS and TRRS connectors. Is there a way for me to write my code so that it works independently of whichever connector is used? Or is there a way to detect what kind of connector is used and react accordingly?