OPL3 offers 18 FM 2-op chans in its standard mode, but that can be configured:
* One setting converts 3 of the FM chans into a 5-chan FM percussion set (Bass Drum, Snare Drum, Tom-Tom, Top-Cymbal, Hi-Hat)
* Another setting pairs 12 of the FM chans into 6 FM 4-op chans
* Both settings can be used at the same time, to obtain 6 FM 4-op chans + 3 FM 2-op chans + 5-chan FM percussion set
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=== FM Percussion Set ===
The OPL3 synthesizes drum sounds using a combination of frequency modulation (FM) synthesis and bit manipulation, which works as follows:
*Bass Drum: Uses FM synthesis between operators to generate a low-pitched percussion sound
*Tom Tom: Direct output of a single operator, with no modulation
*Snare Drum: Combines the phase of a single operator with random noise, mimicking a snare's sharpness
*Cymbal: Created by XOR-ing six bits from the phase of two operators, producing a noisy waveform
*Hi-hat: Similar to the cymbal, but with added random noise for a sharper, metallic sound
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