Answer by ferretnt

Thanks for posting this Mike - hugely helpful when I was debugging iOS audio usage this weekend. It seems that even without AssetBundles, using Stream From Disc on iOS is dangerous with short clips. I have just verified (both with Unity's profiler and Xcode) that if you have lots of short clips (like dialog), and select to stream them in from disc, you then get a single disproportionately large alloc, which shows up in the Unity memory profiler under Assets/AudioManager. I currently have dialog totalling around 8Mb in a scene, and if I set all of it to "Compressed in Memory", then I get a 5.4Mb AudioManager allocation, plus the size of the compressed dialog under Assets/AudioClip. If I set it to "Stream from disc", then I get a ~64kb alloc per audio sample (presumably some header), plus a 15Mb audioManager alloc. The resulting ~10Mb difference between the two builds can be easily measured using Instruments' Activity Monitor. Alex