Time Division

[ColinP]

I'm working on syncing scene morphing to a DAW in the soon to be released Adroit Custom and have a single knob that when synced switches from controlling the tempo of an internal clock to selecting a time division of the DAW's tempo.

The time division range is currently 2, 1, 1T, 1/2, 1/2T, 1/4, 1/4T, 1/8, 1/8T, 1/16, 1/16T, 1/32, 1/32T with 1/8th notes as the 12 o'clock default.

This works nicely from an ergonomic POV and produces well spaced divisions at 96 PPQN so for instance 1/8 = 48, 1/8T = 32. 1/16 = 24, 1/16T = 16.

But this doesn't include dotted divisions where we'd insert 1/16. = 36 and 1/32. = 18 in this sub-sequence resulting in 1/8 = 48, 1/16. = 36, 1/8T = 32. 1/16 = 24, 1/32. = 18, 1/16T = 16.

As you can hopefully see adding dotted divisions makes the pattern more confusing, the spacing less even and selecting the division with a single knob more difficult.

So my question is does anyone ever use dotted time divisions in practice?

[utdgrant]

I use dotted eighth note delays all the time. However, it is always relative to a steady time-signature of 4/4, 3/4 or 6/8.

In saying that, I can't envisage a situation where I'd want morphing to happen on dotted eighth note boundaries.

[seal58]

I did not program time divisions yet, but I'd see it this way:

- regular 1/8 note: division value 1/48
- pointed 1/8 note: 3/2 length of a regular 1/8, so division value should be 2/3 of 1/48, that is 1/72
- 1/8 T: 2/3 length of regular 1/8, division should be 3/2 of 1/48 = 3/96 = 1/32 (So far this is my understanding of a triplet. I'm not really experienced in music theory.)

Instead of using a single selection knob I recommend to add a three state selector (switch/knob/slider) "triplet/regular/pointed" and take that selection for a second division factor 1.5/1/0.666666

[ColinP]

Instead of using a single selection knob I recommend to add a three state selector (switch/knob/slider) "triplet/regular/pointed" and take that selection for a second division factor 1.5/1/0.666666

Yeah, that's effectively the approach that the stock Sync Divider takes...

SyncDivider.png (58.67 KiB) Viewed 2369 times

But I'm a big fan of minimalism and it's really hard to justify adding an extra control for functionality that very few people would ever use (as Grant suggests). Especially as the current setup uses just a single knob for Morph Time, Tempo, Time Division, Offset and Mod Depth depending on context. Plus it's neat and tidy that the Tempo knob transforms into an analogous Time Division knob when one plugs a cable into the Sync In socket.

So I've come up with a compromise which is to add dotted 1/8ths and dotted 1/16ths to the knob options. This takes the knob to 16 steps but that's just within range of what is acceptable from an ergonomic POV.

It's not complete but anyone wanting dotted 1/4 or dotted 1/32 notes can achieve this by messing with tempo multiples.

So for reference by anyone interested in working on time division here are the settings I've settled on...

2 = 768
1 = 384
1T = 256
1/2 = 192
1/2T = 128
1/4 = 96
1/8. = 72
1/4T = 64
1/8 = 48
1/16. = 36
1/8T = 32
1/16 = 24
1/16T = 16
1/32 = 12
1/32T = 8
1/64 = 6

Edited to fix a typo in the table

[utdgrant]

I think that final selection of 16 division options is perfect. It hits the sweet spot between simplicity and being too limited. I imagine it would cover 99% of use cases out of the box.

And as you say, Colin, if you want to dive deep with more complex polyrhythmic or polymetric scenarios, you're working within a modular environment. There are a host of other modules which can be pulled in for such special-purpose applications.

[ColinP]

Cheers Grant. I think it's a good compromise. Adroit Custom's forte isn't polyrhythmic or polymetric stuff but I wanted to offer the basics without people having to resort to fancy sync manipulation which often isn't straightforward to do.

As the morphing (and sequencing) has sample-rate timing resolution I'm extrapolating time from the number of samples between the last two sync pulses then adjusting for over or under shooting once the next sync pulse eventually arrives. It works perfectly with a constant tempo but introduces a slight glitch when tempo is changing. Still the effect is small enough to be inaudible and I want rock-solid timing so there's no option but to do the jitter compensation.

But the algorithm I'm using is very clunky if you change time division while it's playing. But I think most sync systems fall over if you do that anyway. Hopefully most people accept that you need to stop and restart after doing an asynchronous time divisor change. I might look at this again later but my to do list is already way too long.