[sdiy] continuously variable swing

[gregory zifcak]

Michael,
thanks for the input. ok, so if it's 6 pulses per 16th note, that may be 
enough. so assuming that the pulses last for 1/24th of a quarter note, maybe 
i could ignore the last pulse and have 5 positive values (funny, that's the 
value of the strongest swing on the 707), and 5 negative values. i guess 
what you're saying is there's no way to control this pre-cpu. ok i think i 
gotcha, there would have to be a way to skew all of the pulses before they 
hit the cpu. unless i had access to which pulses the cpu triggers the 
samples on. whew. maybe i should just build my own drum machine. i realize 
swing is fairly capable (albeit static) on most drum machines; my point is 
that i need to be able to affect this live in order to get the feel i'm 
after. i've never come across a drum machine that offered variable swing, 
maybe i could modify a korg or roland to go negative. that's a crucial 
aspect. of course i've shifted my sequences by one step to get negative 
swing; the point is that i want to be able to predictably switch from 
pattern to pattern and also slide the notes on a whim. forgive me if this 
seems prehistoric. for me it's crucial to be able to affect tension and 
release spontaneously. listen to some funk drumming and you'll hear the 
shifting. sequencing for recording comes after performance in the way i 
work.
thanks for the insights,
greg

>From: WeAreAs1 at aol.com
>To: zifcak at hotmail.com, dustin.sedlacek at gmail.com, 
>synth-diy at dropmix.xs4all.nl
>Subject: Re: [sdiy] continuously variable swing
>Date: Wed, 13 Jul 2005 02:10:00 EDT
>
>
>
>OK, here's the deal.  Just so you're clear, your Roland drum machine has 
>both
>MIDI clock and DIN Sync clock.  Both DIN Sync and MIDI clock operate at a
>rate of 24 clocks per quarter note.  That is, your drum machine's patterns 
>will
>advance by one quarter note for every 24 clocks it receives.  It will 
>advance
>by one eighth note for every 12 clocks, and one sixteenth for every 6 
>clocks.
>You can extrapolate the triplet subdivisions from these numbers, too --
>Quarter note triplets get 32 clocks; 1/8th note triplets get 16; 1/16th 
>triplets get
>8 clocks, etc.
>
>Typically, when you are trying to add swing to a groove, you are dealing
>either with swung 1/8th notes (as in typical swinging jazz), or swung 
>1/16th notes
>(as found in much hip-hop and funk).  To achieve the swing, you basically
>need to delay the onset of every other note.  With 1/8th notes, you would 
>be
>delaying the "and" beats.  With 1/16th notes, you would delay the "e" and 
>"ah"
>beats.  (if you don't know what those are, do some research on basic music 
>theory
>-- the info is out there on the web).
>
>The problem, as you have already noted, is that there are also a bunch of
>clocks (MIDI or DIN Sync) that happen *between* the beats you're actually
>hearing.  Therefore, if you want to delay every second 1/8th note, you 
>can't just
>delay the 13th, 37th, 61st, and 85th clock pulses (which are the clock 
>pulses
>that the "and's" fall on), you also need to delay the other 11 preceding 
>clock
>pulses -- this way those four important "and" pulses will arrive at the 
>right
>time, and not be confused by the 11 that came before.  Also, you still need 
>to
>have clock pulses #1, 24, 48, and 64 arrive as they normally would, that 
>is,
>undelayed.
>
>The same situation exists with the sixteenth notes, except that you're
>dealing with 6 clocks between swung notes, rather than 12.
>
>To do this with discrete hardware logic would be possible, but it would
>definitely be a bit of a complex circuit.  It might be more easily 
>accomplished in
>the realm of software/firmware in some kind of PIC or AVR-type 
>microprocessor.
>  Of course, you'd want to have your swing amount be variable, and that 
>also
>increases the complexity of the problem.
>
>In order to get a decent range of swing variation, you would basically need
>to remove every other 12 (or 6) clocks from the clock pulse stream, then 
>insert
>12 of your own newly-generated clocks -- but they'd have to be sent out as 
>a
>very fast burst of 12 in series, and the burst would be sent at the
>appropriate moment to get the desired swing effect.  You'd also have to 
>make sure you
>didn't ever delay the burst by too much, because then those delayed clocks 
>would
>start interfering with the clocks for the non-swung downbeats.  Keeping the
>swing amount (or "percentage") constant at different tempos also presents 
>an
>interesting technical challenge -- think about it for a minute, and you'll
>probably see what I mean.
>
>I think it would be very cool to have a "swingalyzer" device that would 
>allow
>you to add continuously variable swing to clocked sequences (for instance, 
>on
>analog CV sequencers that expect one clock pulse per sequence step).
>However, most drum machines already have fairly sophisticated options for 
>swing, so
>I'm not so sure that there's much need there.
>
>Michael Bacich