MRCC 880 issue with patch data sysex not transmitting from PC to synth DIN input

[WireWrangler]

We have not seen this issue in testing.

We have tested with everything from 6 byte messages, all the way to 151KB firmware updates. And we've sent at least megabytes of SysEx data in testing to ensure reliability.

Most MIDI devices specify a SysEx buffer size because they can only receive certain size chunks of data at a time. Sometimes they need that data to be throttled as well. That is something configured in the software used to send the data. If you set that value to something the synth can't consume, it won't work. The MRCC 880 has internal buffers, but this does not have a relation to the above mentioned limitations of the receiving device. 

Here are some screens from MIDI OX I just made, sending and receiving a 37K file in 1024 byte chunks. Sent via MRCC 880 USB 1, routed to DIN 1 Out, connected to an MRCC XpandR which MIDI OX receives as the input for a round trip.

Well, all I can say is that I have tested this extensively -- albeit with this one CZ synth that sends/receives 260 bytes per patch -- and I can say for certain that on macOS the "transmit buffer size" setting in SysEx Librarian -- set at 256 bytes or less -- was what enabled a patch to successfully be transferred from PC to synth with the MRC 880.

And before changing that preference in SysEx Librarian -- it is set to Default typically, which is apparently greater than 256 bytes -- its behavior was exactly like that of the other macOS app I used to test: Patch Base.

And I can also say that all other MIDI interfaces I use on macOS transmit CZ  patches back and forth and work as expected: it's only the 880 the doesn't, and it only has issues from PC to DIN.

Having said all of that, I need to test other devices with sysex and the MRC 880.

And as I said in another thread, otherwise, I really like the MRC 880 - it is sort of what we have always needed for "desktop lab" connections, which is how I am currently deploying it. Thanks for producing it and offering for sale at an affordable price.

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We have not seen this issue in testing.

We have tested with everything from 6 byte messages, all the way to 151KB firmware updates. And we've sent at least megabytes of SysEx data in testing to ensure reliability.

Most MIDI devices specify a SysEx buffer size because they can only receive certain size chunks of data at a time. Sometimes they need that data to be throttled as well. That is something configured in the software used to send the data. If you set that value to something the synth can't consume, it won't work. The MRCC 880 has internal buffers, but this does not have a relation to the above mentioned limitations of the receiving device. 

Here are some screens from MIDI OX I just made, sending and receiving a 37K file in 1024 byte chunks. Sent via MRCC 880 USB 1, routed to DIN 1 Out, connected to an MRCC XpandR which MIDI OX receives as the input for a round trip.

Well, all I can say is that I have tested this extensively -- albeit with this one CZ synth that sends/receives 260 bytes per patch -- and I can say for certain that on macOS the "transmit buffer size" setting in SysEx Librarian -- set at 256 bytes or less -- was what enabled a patch to successfully be transferred from PC to synth with the MRC 880.

And before changing that preference in SysEx Librarian -- it is set to Default typically, which is apparently greater than 256 bytes -- its behavior was exactly like that of the other macOS app I used to test: Patch Base.

And I can also say that all other MIDI interfaces I use on macOS transmit CZ  patches back and forth and work as expected: it's only the 880 the doesn't, and it only has issues from PC to DIN.

Having said all of that, I need to test other devices with sysex and the MRC 880.

And as I said in another thread, otherwise, I really like the MRC 880 - it is sort of what we have always needed for "desktop lab" connections, which is how I am currently deploying it. Thanks for producing it and offering for sale at an affordable price.

The other obvious thing is that the CZ-101 is an ancient device and very likely "can only receive certain size chunks of data at a time" -- as you say.

What mystifies me, though, is why the two pieces of macOS sysex software mentioned previously work perfectly with this ancient synthesizer and any other MIDI router/interface I have used other than the MRCC 880?  

My uninformed intuition says 'some sort of timing issue' -- e.g. it might be necessary to build in a delay between chunks of data transmission, as sometimes occurs in software -- but I have no idea in this context, and I would really appreciate a more informed point of view about any practical way to deal with this on the MRCC 880. 

I have already contacted the software author to see if it is possible to build in a pref for SysEx buffer size.