Thank you very very much for the guidance a few months back. I managed to get those issues resolved, and now I'm facing a bit of perplexity with sound.
I've created around 30 different sound effects (linear PCM, caff, 8k-16k bits per second, stereo, ranging from 40k-200k in size, lasting anywhere from < 1 sec to 5-6 sec in playback.) They sound great, but when the game gets busy, playing a lot of these sounds concurrently starts to drive CPU usage up near 100% on an iPhone 6s Plus.
I've been looking around the web to see if I'm just doing this wrong (I'm using the version of OpenAL/ObjectAL that comes with cocos2d 3.4, and have a singleton that contains buffers, handles and methods for playing each sound. It also preloads the files at initialization. Nothing weird or perverse happening.)
I can post code tonight, but I at the moment I'm starting to suspect that I'm simply trying to do too much sound at once.
Without going from stereo to mono or lowering the bit rate further, I'm thinking I may need to start limiting the number of concurrent sounds by monitoring what's currently playing.
Any general thoughts, rules of thumb or personal experiences with this kind of thing are greatly appreciated!