From a Roland newsletter
Shuffle, a feel that is extensively used - by House, Hip Hop, Rock'n'Roll, Reggae, Jazz - defies strict definition or exact notation. Using 16th notes as the base time value, a Shuffle would lie somewhere between straight 16s (𝅘𝅥𝅯 𝅘𝅥𝅯) and a pattern of dotted 16s and 32s (𝅘𝅥𝅯𝅭 𝅘𝅥𝅰), but not necessarily resolved into a pattern of exact semiquaver triplets (𝅘𝅥𝅮 3 𝅘𝅥𝅯).
Although a number of drum machine and sequencer packages have a 'Shuffle Button', many players would argue that the style can't be taught, let alone reproduced on a machine; it simply has to be felt. But if quantization destroys a Shuffle, where does that leave the sequencer user who has less than spot on timing? Super-MRC's QUANTIZE RATE feature has the answer.
First quantize the part to the smallest straight resolution required - for example, 16th notes (𝅘𝅥𝅯). Next quantize again to 16th triplets (𝅘𝅥𝅯 3), but before committing to the operation, adjust the Rate. This defaults to 1.0 (ie absolute quantization); 0.0 would have no effect, but setting it to 0.5 would give a feel exactly halfway between 16ths and 16th triplets. To try a different feel, requantize to 16ths (at Rate 1.0) then quantize again to 16th triplets at a different Rate - say 0.4 or 0.7. The Shuffle will be proportionately weaker or stronger. The same principe applies to other base values, such as quavers or crotchets.
| RESOLUTION | RATE | Clock pulses in which 16th notes fall |
|---|---|---|
| 16ths (𝅘𝅥𝅯) | 1.0 | 00 24 48 72 00 24 48 72 etc |
| 16th triplet (𝅘𝅥𝅯 3) | 0.0 | 00 24 48 72 00 24 48 72 etc |
| 16th triplet (𝅘𝅥𝅯 3) | 0.3 | 00 26 48 74 00 26 48 74 etc |
| 16th triplet (𝅘𝅥𝅯 3) | 0.5 | 00 28 48 76 00 28 48 76 etc |
| 16th triplet (𝅘𝅥𝅯 3) | 0.7 | 00 30 48 78 00 30 48 78 etc |
| 16th triplet (𝅘𝅥𝅯 3) | 1.0 | 00 32 48 80 00 32 48 80 etc |