Haiku developer François Revol has done an initial port of the Open Sound System to Haiku. OSS has been open sourced by 4front Technologies recently, and powers the audio hardware of many Unix derivates.
This is a companion discussion topic for the original entry at https://www.haiku-os.org/news/2007-07-03_open_sound_system_4_0_is_coming_to_haiku/