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Subject: RE: [AN1x-list] Question: SysExSize Error

From: "Gary Gregson" <gary@...>
Date: 2000-07-30

The unfortunate problem is that USB just doesn't work well with Sysex (its
inherent in the way such interfaces implement the MIDI protocol. i.e sysex
tends to get concatenated together, due to the bandwidth discrepancy between
USB/MIDI and the lack of end to end handshake. The net result is that the
receiving device cannot respond to fast enough!)

You may not see this problem if you are only sending short sysex packets
(such as tweaking a knob on the An1xEdit interface). However for patch dumps
the AN1x uses large numbers of huge sysex messages.....and these must be
correctly timed for the device to respond correctly.

I believe some manufacturers are starting to manage the USB timing problem
within their drivers (i.e. by internally timing how long it 'theoretically'
takes to send a message before reporting to the application that it has
gone.....or by providing some additional software handshake protocol over
USB). However I have yet to see any such interface that is 'rock solid' for
high bandwidth MIDI in a multi device/multi application environment.

hence the only reliable solution is to get a standard serial MIDI interface.

Sorry :-(

Regards

Gary
Email:
gary@...
http://www.yme.co.uk/yme

> -----Original Message-----
> From: Jozej@... [mailto:Jozej@...]
> Sent: 29 July 2000 23:03
> To: AN1x-list@egroups.com
> Subject: [AN1x-list] Question: SysExSize Error
>
>
> I´m working in a projekt studio, with a G4 and a motu midi
> express XT (usb) and every time i try to load a sound from the
> AN1X editor i get the SysExSize error - can anybody help me to
> solve this problem???