This is the problem of the bogus Teac USB interface in UD-501/UD-503. Freezing happens when frequency of the sound files changes. This has already been been fixed in the mainline kernel.
https://github.com/raspberrypi/linux/commit/465cc6de211a88a8af978fd8e1d07e6a453a31c4
You need at least kernel 3.10.98 (Odroid has 3.10.80).
By the way,t he new Raspberry Pi2/3 includes that quirk and the UD-503 runs for days without freezing.