Bug? Bug with MIDI-to-USB or USB Adapter Mode?

JSXtremist

JSXtremist

Inspired
I believe there is a bug with transferring MIDI over the Axe-Fx II USB port, or the USB Adapter Mode itself. This seems to be a related topic:

http://forum.fractalaudio.com/axe-f...nal-midi-destinations-mdc101-thru-axe-ii.html

To simplify my setup, I'm attempting to use the Axe-Fx II as a MIDI-to-USB interface for a computer (USB Adapter Mode is turned on) with a MIDI foot controller plugged directly into it, rather than using a separate MIDI interface. Bome's MIDI Translator Pro is monitoring MIDI messages on the computer.

This setup looks like this:

foot controller > Axe-Fx II (MIDI In to USB) > computer

For example, switch #15 on the foot controller is programmed to send:

B2 1D 7F (ch. 3: #29, 127) - ON
B2 1D 00 (ch. 3: #29, 00) - OFF

However, rather than simply passing "B2 1D 7F" or "B2 1D 00" along from the controller, the Axe-Fx II's USB port is relaying something like this to the computer (I will press switch #15 on the controller 6 times)...

B2 9E 28
1D
7F
B2 EA 20
1D
00
B2 0F BC
1D
7F
B2 8A F6
1D
00
B2 F7 41
1D
7F
B2 F1 55
1D
00

So the problem is that the Axe-Fx II *changes* the hex into...

B2 xx xx (ON)
1D
7F
B2 xx xx (OFF)
1D
00

("xx" = two randomly changing bits added by the Axe-Fx II's USB port)

This problem doesn't occur if I use the Axe-Fx II's MIDI Out/Thru and/or a separate MIDI interface, such as an M-Audio Midisport 2x2.

These setups work perfectly (the computer receives only "B2 1D 7F" and "B2 1D 00")...

A) foot controller > Midisport 2x2 > computer
B) foot controller > Axe-Fx II (MIDI In to MIDI Out/Thru) > Midisport 2x2 > computer

Why is the Axe-Fx II's USB Adapter Mode adding two extra random hex bits per MIDI command?
 
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I suspect this is a bug in the Apple driver. Their Audio Class 2.0 driver seems rife with bugs.
 
I've been able to replicate this problem on my Mac using a keyboard controller and the AxeFx. I filed a bug but, like Cliff mentioned: the problem is likely with OS X libraries. :(
 
With the Midisport 2x2 as the MIDI interface for the foot controller, the computer receives the hex message "FE" about five times per second. There is no problem with this setup; I'll easily translate the 3-bit strings (such as "B2 1D 7F") from the foot controller into computer keystrokes using Bome's MIDI Translator.

To demonstrate, I now have the foot controller connected to the Midisport 2x2. I will press switch #15 on the controller 6 times...

FE
FE
B2 1D 7F
FE
FE
B2 1D 00
FE
FE
FE
B2 1D 7F
FE
FE
B2 1D 00
FE
FE
FE
FE
B2 1D 7F
FE
FE
B2 1D 00
FE
FE
FE
FE
FE
FE
FE ("FE" will infinitely repeat while controller is idle)

On the other hand, when using the Axe-Fx II as the MIDI interface for the foot controller, I cannot define translation rules in Bome's MIDI Translator because two random hex bits are added to all MIDI messages. As a side note with this setup, the "FE" messages from the foot controller are not being received by the computer.

B2 9E 28
1D
7F
B2 EA 20
1D
00
B2 0F BC
1D
7F
B2 8A F6
1D
00
B2 F7 41
1D
7F
B2 F1 55
1D
00
 
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If it's a bug in the Apple driver, then why doesn't the problem (two random hex bits being added to all MIDI messages) occur when using the Midisport 2x2 as the MIDI interface with my Mac? I'm trying to simplify my rig by using the Axe-Fx II as the MIDI interface.
 
JSXtremist said:
If it's a bug in the Apple driver, then why doesn't the problem (two random hex bits being added to all MIDI messages) occur when using the Midisport 2x2 as the MIDI interface with my Mac? I'm trying to simplify my rig by using the Axe-Fx II as the MIDI interface.
Click to expand...

Is the midisport class compliant or does it use it's own drivers?
 
JSXtremist said:
If it's a bug in the Apple driver, then why doesn't the problem (two random hex bits being added to all MIDI messages) occur when using the Midisport 2x2 as the MIDI interface with my Mac? I'm trying to simplify my rig by using the Axe-Fx II as the MIDI interface.
Click to expand...
I'd think that it has to do with the MIDISport using it's own drivers vs the Apple Audio drivers that the AxeFXII interface utilizes.

That MIDISport 2x2 is just the damn best MIDI interface I've ever used on a PC machine; not surprised one bit that it works great on Mac as well. I don't like a lot of their stuff, but they got that thing right. Just about every other USB based MIDI device has some kind of issue, especially when dealing with sysex.
 
shasha said:
I'd think that it has to do with the MIDISport using it's own drivers vs the Apple Audio drivers that the AxeFXII interface utilizes.
Click to expand...

Yup. Pretty sure it's this.

But you just gave me a good test case to try. I'm going to see if OS X will recognize my UM-1G without the drivers installed and see what happens.
 
No the axefx does not have its own USB midi drivers. It has a small firmware installer driver. The axefx uses the built in os x drivers
 
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