H. Gluender wrote: > Robert Purves has provided the code for simultaneous (actually, it > isn't totally simultaneous on my 7600 machine) sound reproduction in > the left and right stereo channels The demo that I posted yesterday did not explicitly synchronise the start of the sounds in left and right channels, partly because on my Mac under 10.3.6 they were already fully synchronised, and partly because I did not know that the Sound Manager has the ability to synchronise. After reading Herbie's report, I tried the demo under Classic (9.2) and indeed there is a distressing time delay between channels :-( The fix requires one function in the demo to be changed. PlaySimultaneousSounds now issues _syncCmd so as to prevent the channel sounds from starting independently. The final _syncCmd starts both channels at the same instant. This works properly in both Classic and OS X. // improved version with channel synchronisation 30 Nov 2004 local fn PlaySimultaneousSounds( leftH as Handle, rightH as Handle ) '~'1 dim as SndCommand cmd dim as OSErr ignore // prepare synchronisation cmd.cmd = _syncCmd cmd.param1 = 3 cmd.param2 = 12345678 // arbitrary identifier ignore = fn SndDoImmediate( gLeftChannel, cmd ) cmd.param1 = 2 ignore = fn SndDoImmediate( gRightChannel, cmd ) // set up sounds ignore = fn SndPlay( gLeftChannel, leftH, _true ) ignore = fn SndPlay( gRightChannel, rightH, _true ) // start both channels synchronised cmd.param1 = 1 // 1 means start now ignore = fn SndDoImmediate( gRightChannel, cmd ) end fn Robert P.