With Ru5tK1ng&#039;s updated IDL WAD (idl2013p.wad), certain MIDI songs appear to cause grief such as drops in the frame-rate, particularly on MAP20. I was able to successfully track down the cause of the issues: some MIDI songs have a hundred or more duplicate MIDI event messages playing at the same time. <br /><br />When Odamex starts to play a new song, it initializes the PortMidi library with an event buffer size of 100. With these certain problematic MIDI songs, that buffer gets filled with duplicated event messages and from that point on, the behavior is &quot;undefined&quot;. For Windows users, this issue causes huge slowdowns and for Linux users it appears to just cause some MIDI notes not to play.<br /><br />So I&#039;ve fixed this problem by initializing the PortMidi library with an event buffer size of 1024. I&#039;m sure updated binaries will be floating around soon, however, you can also work around this problem by completely disabling music with &quot;set snd_musicsystem 0&quot; from the console.