How to Optimize Channels in Impulse Tracker for the
Gravis Ultrasound
The Ultrasound's most notable limitations have
always been (excluding the horrible handling of
16-bit samples)
(1) Lack of adequate panning positions
(only 16)
(2) Lack of mixing resolution at greater than
14 channels
Impulse Tracker goes a long way toward resolving
the latter limitation. Starting with version 2.x,
Impulse Tracker features a GUS driver which constantly
re-initializes the soundcard, continually reassuring
that the highest possible mixing resolution is being
used.
As a composer, there are a few things you need
to do to make the most of this feature. First,
Impulse Tracker can only optimize for the highest
active channel. This means that if you're using only
14 channels, but a sample is being played in the 18th
channel, then Impulse Tracker will have to initialize
for 18 channels. Of course, this does not have grave
implications for songs that skip a couple of channels
and leave something playing in the 16th channel when
only 14 channels are being used. However, if you're
only using 10 channels, and you happen to have a sound
playing in the 25th channel, the song will sound much
worse than it needs to.
The second thing you as a composer must do, is to be
cautious of looping samples. A common tendency is to
disable looping samples by sliding the volume to zero.
The sample is still playing; you just can't hear it.
It's one thing if you intend to turn the sample back
on at some point. However, if you're done with the
sound, make sure to use a channel off command so that
Impulse Tracker can re-initialize for less channels.
Finally, you can, in fact, know how many channels
are being used at any given time. To do this, press
Shift-F5. This will bring up the driver options for
the currently enabled sound device. Next, select and
enable the option "Show channel reinitialisation"
(sic). This will allow you to always know how many
channels are being used. This feature could be more
useful if the number were always visible at a glance,
but alas, the number is only visible for a split-
second during reinitialization.
That's all you need to know to successfully optimize
channel use for the GUS. Soon, we'll all have
Interwave cards, and all the problems with the regular
GUS will be solved. Until then, take care in your
channel use. I believe software GUS routines are on
the way, but getting the same quality at the same
mixing speed is impossible, so such a routine will be
of questionable value. Time will tell.
Happy Tracking! :)
Freejack / Beyond
Christopher Barton
Contact: cbarton@interaccess.com
Web: http://homepage.interaccess.com/~cbarton
http://www.mcs.com/~beyond
