Step Sequencers

Dave Peachey · Novice Joined: 19 Feb 2007 Posts: 43 Location: London

All,

I know that ZEIT has the facility to utilise an external MIDI keyboard to transpose, in real time, the notes played by one or more sequences but I wonder whether or, indeed, how this might be done using another sequence to effect something similar as I recollect some of the older hardware CV sequencers could do (if I'm not mistaken in my recollection - or am I just making this up?).

I've thought about a couple of ways to do this - one seems to (well, might) work using the current facilities available within ZEIT, one would (unless it's there and I can't see it) require some additional fancy coding.

Using the facilities currently available within ZEIT
For the purposes of the following discussion, I'll assume that Sequence A is the one controlling the main note values and Sequence B is the one providing the note transposition.
- Assign both Sequence A and Sequence B to the same MIDI channel
- Assign one of the continuous controllers of Sequence B to whichever parameter on the synthesizer deals with the fine tune adjustment
- Set Sequence B to run at the appropriate fraction of the speed of Sequence A that enables Sequence B to update from note/step n to note/step n+1 at the point at which Sequence A restarts
- Play it and see what happens

I can see a number of issues with this approach not the least of which are:
- Getting the relative speeds of each sequence to the right speed so that the reset to note 1 of Sequence A coincides with the switch from note/step n to note/step n+1 of Sequence B
- Assumes that you can assign a CC to the fine tune parameter in the first place
- Operates at the synthesizer end of the chain not within ZEIT
- Precludes the dynamic switching of step mutes and/or skips
- Requires you to dedicate two sequence channels to one music stream
- It's all a bit hit-and-miss and not very user friendly

An alternative approach
My other alternative would require some new (and probably very fancy) code to do it but might work and have benefits as follows:
- Sequence A is assigned to the note values being played by the synthesizer
- Sequence B is assigned to modify (transpose) - perhaps using one of its CC lines - the notes being generated by Sequence A in a fashion similar to the Keyboard transpose process which already exists
- Some form of coded flag would be required to tell Sequence B when Sequence A resets to the first note of the sequence so that Sequence B could advance from note/step n to note/step n+1
- Could account for skips in Sequence A
- Would allow a mute step in Sequence B to silence Sequence A for the entirety of one cycle of Sequence A
- Could allow you to use Sequence B to modify/transpose not just Sequence A but Sequences C to H as well if there was an appropriate parameter for every sequence channel allowing you to select which sequence is the modifier (rather than hard-coding it)
- By the same logic, could allow for so very complex (probably quite random!) cross-modulation of sequences
- Keeps everything within ZEIT so that the only thing required of the synthesizer is to react to note value changes on one (or more) channels

Again, I can see a number of issues not the least of which are:
- Requires (as I can see it) a lot of new code to be written
- Requires you to dedicate a sequence channel to operate as a sequence transposer/modifier unless some really clever coding allowed you to save/store/use one of the CCs lines in Sequence B to control Sequence A at an appropriate fraction of Sequence A's rate whilst using Sequence B's note value line to control another note channel (but, then, you'd have potential issues with resetting Sequence B!)
- Probably requires too much processing power or code storage space to make it practical

In conclusion
Bear in mind that the above is rather sketchy and not fully thought through at a technical level and also that I'm not actually asking David to do this as:
- he's got far too much on his plate at present just building and delivering instruments
- as has been commented elsewhere, ZEIT is already incredibly well endowed with features
it's just that I would be interested in peoples' views on what I've set out above.

Cheers
Dave

BirdFLU · Newbie Joined: 29 Jan 2007 Posts: 184 Location: PDX, OR

I think I understand what you're looking for. Off the top of my head, I know the Doepfer MAQ 16/3 has something like what you've described. You could use one sequence to transpose the values of another, have them running at different rates, etc. You could have one sequence alter the values of notes, gate, velocity, whatever.

I sold my MAQ years ago though because it wasn't very good at anything it did. It had all these great features that were half done or done in such a way that they were practically unusable. But my MAQ rant is another story...

If the MAQ could do what you're asking, I'm sure other sequencers do it and the Zeit will eventually.

Dave Peachey · Novice Joined: 19 Feb 2007 Posts: 43 Location: London

David,