Patches and discussion for Ensoniq VFX family

This is a heads up to all of you.  If you know of a better forum I
should be posting this in, let me know.

Having recently put some softsynth software on my mac laptop, I wanted
a usb - midi interface that I could just put in my laptop bag and have
with me.  There are a bunch of cheap, 1x1 usb midi adapters available
on ebay for around $20 after shipping.  I could not find much
information on whether these worked well or not, using google.  So I
thought I'd try one.

I hooked it up to my VFX-SD and things were NOT working well.  I tried
it with my Macbook laptop and with my windows XP desktop machine.  In
both cases, the symptoms were the same.  A single note would play
fine, but chords would not, no matter how much time between pressing
each note.  And there were stuck notes, etc.

So the short story is: you may get even less than you pay for if you
try to use one of these with a VFX.

I looked at the output with Midi-Ox, and I think I may have a clue to
the problem.  The rest of this message is pretty much pure speculation.

It looks like this device does not handle running status correctly.
And at least my VFX-SD seems to send running status whenever it can.

	Running status is a midi feature that's been around from the
	begining of midi.  Status bytes have the high bit set (decimal
	value is greater than 127), other bytes don't.  For example, a
	note on message looks like A0 45 40 (in hexadecimal).  A0 is a
	status byte that says "this message is a NOTE ON message for
	midi channel 1." 45 is the note number, and 40 is the
	velocity.  If more note on messages need to be sent for
	channel 1, the sender is allowed to send just more note
	number, velocity byte pairs, without sending the initial byte,
	so: A0 45 40 47 42 would be two note on messages on midi
	channel 1, one for note 45 velocity of 40, one for note 47
	velocity of 42.

This midi interface doesn't seem to react to anything unless there's a
status byte.  So, Note-On,  Note-off, Note-On, Note-off works, but
Note-On, Note-On, Note-off, Note-off doesn't.

I've heard that these interfaces are rip-offs of the M-Audio midisport
uno; I found this info in the linux alpha drivers section:

   - usb-audio: work around broken M-Audio MidiSport Uno firmware
     
     The firmware of the M-Audio USB Uno MIDI Interface has, at least in
     hardware revision 1.25, a bug that garbles its USB output.  When it
     receives a Note On MIDI message that uses running status, the resulting
     USB MIDI packet has a wrong CIN (4 instead of 9) and a wrong length
     (2 bytes, the status byte is still missing).
     
     This patch adds a workaround to track the CINs and the MIDI messages of
     received USB MIDI packets to detect whether a packet with CIN 4 is a
     correct SysEx packet or a buggy running status packet.

That suggests that this is probably a bug-for-bug-compatible clone,
and that a workaround is proably already in the other platforms'
USB-MIDI drivers, if only they could be convinced to see this device
as a midisport uno. :-(

Anyway, buyer beware!

--> Steve

-- 
Steve Wahl    steve@...

One day, the light bulb in the fridge burnt out, and I thought to myself,
"At least now I know it's off when the door's closed... Or do I?"

On Fri, Jun 20, 2008 at 02:47:17PM -0500, Steve Wahl wrote:
> 
> 	Running status is a midi feature that's been around from the
> 	begining of midi.  Status bytes have the high bit set (decimal
> 	value is greater than 127), other bytes don't.  For example, a
> 	note on message looks like A0 45 40 (in hexadecimal).  A0 is a
> 	status byte that says "this message is a NOTE ON message for
> 	midi channel 1." 45 is the note number, and 40 is the
> 	velocity.  If more note on messages need to be sent for
> 	channel 1, the sender is allowed to send just more note
> 	number, velocity byte pairs, without sending the initial byte,
> 	so: A0 45 40 47 42 would be two note on messages on midi
> 	channel 1, one for note 45 velocity of 40, one for note 47
> 	velocity of 42.

Sorry to reply to my own host, but I was screwed up in that
description.  Note on messages start with a 9, not an A, so the two
examples should be "90 45 40" and "90 45 40 47 42".   Sorry 'bout that.

--> Steve

-- 
Steve Wahl    steve@...

"On this employee survey form, it asks, 'Do you trust your manager?'
If I trust him to do the wrong thing, is that a 'yes'?"

I think I have been using the MidiMan UNO for the 1x1 stuff without a problem....

Bob
El Segundo, CA



-----Original Message-----

>From: Steve Wahl <steve@...>
>Sent: Jun 20, 2008 3:47 PM
>To: Ensoniq-VFX-SD@yahoogroups.com
>Subject: [Ensoniq-VFX-SD] Beware cheap chinese USB MIDI cables on ebay...
>
>This is a heads up to all of you.  If you know of a better forum I
>should be posting this in, let me know.
>
>Having recently put some softsynth software on my mac laptop, I wanted
>a usb - midi interface that I could just put in my laptop bag and have
>with me.  There are a bunch of cheap, 1x1 usb midi adapters available
>on ebay for around $20 after shipping.  I could not find much
>information on whether these worked well or not, using google.  So I
>thought I'd try one.
>
>I hooked it up to my VFX-SD and things were NOT working well.  I tried
>it with my Macbook laptop and with my windows XP desktop machine.  In
>both cases, the symptoms were the same.  A single note would play
>fine, but chords would not, no matter how much time between pressing
>each note.  And there were stuck notes, etc.
>
>So the short story is: you may get even less than you pay for if you
>try to use one of these with a VFX.
>
>I looked at the output with Midi-Ox, and I think I may have a clue to
>the problem.  The rest of this message is pretty much pure speculation.
>
>It looks like this device does not handle running status correctly.
>And at least my VFX-SD seems to send running status whenever it can.
>
>	Running status is a midi feature that's been around from the
>	begining of midi.  Status bytes have the high bit set (decimal
>	value is greater than 127), other bytes don't.  For example, a
>	note on message looks like A0 45 40 (in hexadecimal).  A0 is a
>	status byte that says "this message is a NOTE ON message for
>	midi channel 1." 45 is the note number, and 40 is the
>	velocity.  If more note on messages need to be sent for
>	channel 1, the sender is allowed to send just more note
>	number, velocity byte pairs, without sending the initial byte,
>	so: A0 45 40 47 42 would be two note on messages on midi
>	channel 1, one for note 45 velocity of 40, one for note 47
>	velocity of 42.
>
>This midi interface doesn't seem to react to anything unless there's a
>status byte.  So, Note-On,  Note-off, Note-On, Note-off works, but
>Note-On, Note-On, Note-off, Note-off doesn't.
>
>I've heard that these interfaces are rip-offs of the M-Audio midisport
>uno; I found this info in the linux alpha drivers section:
>
>   - usb-audio: work around broken M-Audio MidiSport Uno firmware
>     
>     The firmware of the M-Audio USB Uno MIDI Interface has, at least in
>     hardware revision 1.25, a bug that garbles its USB output.  When it
>     receives a Note On MIDI message that uses running status, the resulting
>     USB MIDI packet has a wrong CIN (4 instead of 9) and a wrong length
>     (2 bytes, the status byte is still missing).
>     
>     This patch adds a workaround to track the CINs and the MIDI messages of
>     received USB MIDI packets to detect whether a packet with CIN 4 is a
>     correct SysEx packet or a buggy running status packet.
>
>That suggests that this is probably a bug-for-bug-compatible clone,
>and that a workaround is proably already in the other platforms'
>USB-MIDI drivers, if only they could be convinced to see this device
>as a midisport uno. :-(
>
>Anyway, buyer beware!
>
>--> Steve
>
>-- 
>Steve Wahl    steve@...
>
>One day, the light bulb in the fridge burnt out, and I thought to myself,
>"At least now I know it's off when the door's closed... Or do I?"

On Fri, Jun 20, 2008 at 05:29:40PM -0400, Bob S. wrote:
> I think I have been using the MidiMan UNO for the 1x1 stuff without a problem....

The info I have suggests that, for (certain versions only of) the UNO,
the USB midi driver must do a software work-around because the
hardware and/or on-board firmware doesn't react right to running
status.

If that's true, the driver reads the devices id numbers, sees it's a
MidiSport UNO, and in particular the version that needs the
workaround, and enables the software work-around.

Since this cheap knock-off I have reports different ID numbers (so
software doesn't identify it as a M-Audio interface), it would not
know it needs to enable the software workaround.

This is all based on theory, however it's still true that the
interface doesn't work for beans.

--> Steve

-- 
Steve Wahl    steve@...

"Music fans listen to music, whereas audiophiles listen to stereos."
   -- quoted by "sqldr" on Slashdot