Some amateur compression tools break the looping of XA audio. If the music restarts abruptly, find a CHD made with a newer version of chdman.
: Originally designed for playing PS1 games on the PSP, this format supports multi-disc games in a single file. While popular for its portability, some consider it "lossy" because it can be harder to restore to a clean original state for patching. Ps1 Highly Compressed Games