I've made a substantial rewrite of the SB driver to make it do full
duplex on an SB16.  Because of the braindead design of the SB the
input and output have to use different precisions (8 and 16 bits).  

It is possible to set the driver to use 8 bits on both input and
output and it will then emulate 8 bits on the output by expanding the
samples to 16 bits.  Currently you cannot set both input and output
to 16 bits (it would require a lossy transformation).

I've tried the driver for quite a while now and it works for me,
but I have a SB64 so I can't really tell how well it works on
other cards.  If you have any problems please tell me.

Note.  If you want to use full duplex you need to open it O_RDWR,
use AUDIO_SETFD (to set full duplex) and then set the mode to
AUDIO_PLAY|AUDIO_RECORD.  I know this is cumbersome, but having
the driver start in full duplex mode when opned with O_RDWR (which
is the logical thing to do), just broke too many programs.

        -- Lennart