When gt cannot find a patch for a melodic instrument in banks 1-127, it
uses a patch from bank 0 and assumes the bank number is a "variation" bank.
Variation bank voices are produced by fiddling with the parameters of basic
bank 0 voices.  For XG midis, banks 1-16 are taken to be variation voices,
even when patches in those banks actually exist, because the GM/GS usage
of these banks is totally different from that for XG.


		XG variation bank effects

Variation bank
--------------

	 1		KSP: pseudo-stereo panning
	 2		KSP: pseudo-stereo panning right to left
	 3		Stereo: second pseudo-stereo voice
	 4		With LFO: lfo controls cutoff freq. of lp filter
	 5		Without LFO: no lfo
	 6		Single: cancels stereo voice
	 8		Slow: envelope attack time increased
	12		Fast Decay: envelope decay time decreased
	14		Double Attack: (not implemented)
	16		Bright: brightness increased some; reverb raised an octiave
	17		Bright: brightness increased more; reverb raised an octiave
	18		Dark: brightness decreased some
	19		Dark: brightness decreased more
	20		Resonant: harmoniccontent increased
	24		Attack Transient: (modulation of filter freq. increased) pitch modulation added
	25		Release Transient: (modulation of filter freq. decreased) pitch modulation added
	27		Rezo Sweep: modulation of filter freq. increaeed; other adj.
	28		Muted: modulation of filter freq. decreaeed; other adj.
	32		Detune1: chorus depth set to 30
	33		Detune2: chorus depth set to 60
	34		Detune3: chorus depth set to 90
	35		Octave1: reverb/chorus extra notes raised 12 semitones
	36		Octave2: reverb/chorus extra notes lowered 12 semitones
	37		5th1: reverb/chorus extra notes raised 7 semitones
	38		5th2: reverb/chorus extra notes lowered 7 semitones
	39		Bend: chorus depth set to 120
	40		Tutti: low volume mallet added
	41		Tutti: medium volume mallet added
	42		Tutti: high volume mallet added
	43		Velocity Switch: low volume mallet added; high volume above velocity 120
	45		Velocity Crossfade: variable volume mallet added; increases by velocity
	52		Tutti: low volume mallet added
	53		Tutti: low volume mallet added
	54		Tutti: low volume mallet added
	64		other similar wave: (not implemented)
	65
	66
	67
	68
	69
	70
	71
	72
	96		dissimilar wave: (not implemented)
	97
	98
	99
       100
       101
       ...