Do your changes affect synthesizers on soundcards? As eg midi2 in sb0 at isa0 port 0x220-0x237 irq 5 drq 1: dsp v3.02 audio1 at sb0: half duplex, mmap, independent midi1 at sb0: SB MIDI UART opl0 at sb0: model OPL3 midi2 at opl0: SB Yamaha OPL3 best regards Matthias