There is a bug in almost all ALAC converter implementations which uses a 16-bit integer to store the sample rate. This overflow causes all these files to play back at 30464 Hz. To maintain compatibility, current players should detect this and play the file back at 96000 Hz. I suggest you use refalac to encode high sample rate files to M4A ALAC. This outputs valid M4A files that play back properly. However multichannel ALAC is not very useful at this time because even iTunes cannot play it back. Only stereo ALAC is reliable. There are too any file corrupting bugs with multichannel / high sample rate ALAC software.