The release of MorphOS 3.13 exposed a long standing bug in ixemul.library: Due to an oversight the library defaults to a wrong FPU rounding mode. The bug can manifest itself in various ways, one example is "tinny" audio output in various games. Only applications using ixemul.library are affected. We have released a hotfix that addresses this issue.
Please download the archive, unarchive it, and follow the instructions in the accompanied README file to complete the installation.