[sdiy] midi and clock sync (fault analysis)

[Julian]

>> http://www.zen9084.zen.co.uk/test.wav
> These offsets are much more than the 9ms you measured. The delay is not caused in the MIDI-line, but when Audio is produced. What 
> drum machine is this?
>
> I could imagine that the cause is an awfully bad MIDI/Audio-Handling in the drum machine.


Thank you for your input Florian,

He was testing with a mfb drum machine, but says he has also tested with -

>MFB-522
>TR-626
>Gameboy synced through arduinoboy
>Different Linux software (Hydrogen, SEQ24, ALSA Modular Synth, ...)

Im just looking at the midi data here, whilst it seems that he was using his ears.

I asked him to look at the midi data, but he had no way of merging the output from the master, and the output from the slave to get 
direct analysis.


Since my initial tests, i have tested with another x0xb0x, and that also shows a 9ms delay on the very first synced note (all 
subsequent notes have 0/1ms delay)
I would then be inclined to believe that the 9ms shown on the first cycle has little to do with the symptoms present in the .wav 
file, and can be considered normal and/or of no consequence, esp as, again, all subsequent cycles show no significant delay.


The midi data output by a x0xb0x is not particularly dense either.  There is the RUN command, the clock data, Note On/Off and the 
STOP command.  There are no CCs/Sysex or anything to significantly load the serial interface at all.

This is very confusing, as the owner seems to have run tests which point toward the fault being with the x0xb0x unit, however, i can 
find no flaw whatsoever with the unit itself.  Unfortunatly, i am not able to recreate his test enviroment myself.

Any further comment you may have would be most welcome!

Thanks again,
Julian











----- Original Message ----- 
From: "Florian Anwander" <fanwander at mnet-online.de>
To: "synthdiy" <synth-diy at dropmix.xs4all.nl>
Sent: Tuesday, December 29, 2009 12:38 PM
Subject: Re: [sdiy] midi and clock sync (fault analysis)


> Hello Julian
>
>> http://www.zen9084.zen.co.uk/test.wav
> These offsets are much more than the 9ms you measured. The delay is not caused in the MIDI-line, but when Audio is produced. What 
> drum machine is this?
>
> I could imagine that the cause is an awfully bad MIDI/Audio-Handling in the drum machine.
>
> Florian
>
> _______________________________________________
> Synth-diy mailing list
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