The behavior is still very consistent. Going to try some other sound cards I have and see if I can reproduce the issue with them as well.

Hey Vogons, long time reader first time poster. My main squeeze is 98SE on a p4p800 mobo w/ P4 2.6ghz with 512mb ram, a GeForce ti4200, and a YMF724F with midi out to a first gen MT-32. If I boot straight to DOS and load the Yamaha tsr (setupds, ymfirq, dsdma), SoftMPU hangs on "SoftMPU active at …