neither.
i found that the answer to all my problems is simply to run aumix, then run kmix, and both times remember to turn up all the volumes, and i think save the settings.
I am not sure what this actually does, but it creates the right block device or something, one or both of the apps creates the right symlink and so on to make it all happen, and for /dev/dsp to be recognised as the block device for sound.
that's a guess, so if that sounds like bullshit... it is.
Also, i haven't had any problems with sound in mandrake 9.0, only with 8.0 and 8.2...