Analogue-sequencer

What's the midi and CV timing like on the Cirklon? 
I'm hoping that it'll be tighter than the USB midi seen on most DAW's with their jitter and latency.
Are all  Cirklon midi ports addressed in parallel so there's no latency?
Any real world timing figures? 
For example I once tested an Atari (remember those? ;-) to have midi jitter of around 2ms. How does the Cirklon compare?
Cheers

>>What's the midi and CV timing like on the Cirklon?<<

can't speak for the cv yet, as the board hasn't arrived, but the midi timing is.... when I got my cirklon, I set it playing a simple monophonic part of 16 steps, & it reminded me of using my old arp 16xx.

it's extremely tight. I think colin's a bit obsessive about this particular area, & it's one reason why the cirklon has multiple midi ports.

I've been using all sorts of hardware sequencers for years, both cv-gate & midi, & recently got involved with a bunch of octopus users to resolve a multiple-sequencer timing issue that required measuring timing spread down to a few mS. the cirklon has no such issues.

:-)

d.

> What's the midi and CV timing like on the Cirklon? 
> I'm hoping that it'll be tighter than the USB midi seen on 
> most DAW's with their jitter and latency.
> Are all  Cirklon midi ports addressed in parallel so there's 
> no latency?

Well I am pretty picky about timing.
Each of the 5 MIDI ports are served by an independent serial port in the CPU
core itself.
I chose the CPU specifically for its high number of UARTs.
There is no generic RTOS involved. The sequence engine is triggered directly
by a hardware timer which runs on a 250uS interval.
The CV outputs are handled by a slave CPU connected via a fast SPI link,
with a 1ms refresh period for the 16 CV channels.
Changes to the gate outputs are applied in parallel.
In theory, the best thing to do would be to update the gate outputs as fast
as possible.
But if you have optimised the timing of MIDI synths (using a dedicated MIDI
bus per synth) that still gives you 1ms latency on the transmission of the
first note on to each instrument.
So it may be better to build-in a delay of 1ms to the internal gate outputs,
so they are synchronous with the MIDI-attached synths (assuming minimal
latency on the MIDI synths)

> Any real world timing figures? 
> For example I once tested an Atari (remember those? ;-) to 
> have midi jitter of around 2ms. How does the Cirklon compare?

I haven't taken any direct measurements for a while.
The feedback from users has been that it sounds noticably tighter than a P3.
What was the figure of 2ms for on the Atari ?
Depending on how a sequencer app is written, the jitter can vary widely on
the same harware platform.
There are also different causes of jitter, some of which may be less of a
problem, or even desirable.
The classic Roland devices - 303, 606, 808 and 909, all have their voice
triggering synchronised to an internal 2ms time interval.
Depending on how the tempo timebase interacts with the fixed 2ms timer, that
gives you a variety of cyclic 'swing' patterns, with a maximum deviation on
any beat equal to one 192ppqn tick at 120bpm.
Given the higher timing accuracy of Cirklon, I'm looking at whether to allow
a deliberate increase of the timer period, to loosen up the timing.
That applies only to the relative timing of each clock tick - note triggers
on the same tick must happen as close to simultaneously as possible.

Best regards,
Colin Fraser
Sequentix Music Systems Ltd
http://www.sequentix.com

--- In analogue-sequencer@yahoogroups.com, "Colin Fraser" <colin@...> wrote:

> What was the figure of 2ms for on the Atari ?

This was tested with Notator 3.1, with Log3 and Unitor2 interfaces plugged into the Atari. Notator was loaded with all tracks firing out 16ths. I'd wired a midi lead with a jack socket one end, and from one of the Unitor2's midi outs, recorded midi "pulses" as audio. I then checked the timing between each midi note on pulse, and worked out the "worst case"  jitter from the counts.

Relieved to hear the Cirklon is going to be tight!!!

Any progress on the video's please Colin? Really looking forward to these.