[sdiy] Bunching of MIDI clock messages

[Adam Inglis]

Hi Richie
David from Innerclock has looked at this extensively, at least  
empirically, in his quest to improve timing accuracy between computer  
DAWs and hardware instruments.
Check out
http://www.innerclocksystems.com/New%20ICS%20Litmus.html
for some real world numbers




regards
Adam Inglis
http://www.adambaby.com

On 11/09/2013, at 9:32 PM, rburnett at richieburnett.co.uk wrote:

> How common is "bunching up" of MIDI clock messages due to erratic  
> transmission out of sequencers?
>
> For example, if I check for the reception of a MIDI clock message  
> every 2 millisconds in a receiving instrument is that sufficient?   
> (In theory 2ms polling rate should be sufficient to support tempo up  
> to 1250 BPM provided the clock events arrive with even spacing!)  Or  
> do you think I should cater for the possibility of receiving as many  
> as seven MIDI clock events transmitted "nut to butt" over my 2  
> millisecond polling period!?!?
>
> I know the MIDI specifications says that MIDI clock messages are to  
> be transmitted with even spacing at the average tempo rate, but I  
> don't think i've ever seen a maximum jitter specification anywhere?   
> (I can just imagine sequencer software getting preempted in a  
> Windows environment, and later transmitting all of the overdue MIDI  
> data in an intense burst.)
>