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        MIDI-OX >> Mapping Questions >> Sysex variables
        
(Message started by: JeanFi on Feb 11^th, 2019, 3:06pm)

Title: Sysex variables
Post by JeanFi on Feb 11^th, 2019, 3:06pm

Hello

There is something I do not understand about midi-ox sysex variables FC, FA and FB.

If I understood correctly, FC used for channel change and must be insert in the corresponding byte.

FA and FB serv would go for LSB MSB variables ? What is the difference between FA and FB ?

Specifically I want to map CC messages sent with a synthesizer (access virus) sysex messages that would be drive commands of a sampler (akai S2000).

The structure of a sysex message of the sampler is for example :

F0 47 00 42 48 chan 00 01 17 00 01 00 lsb msb F7.

So where do I place FA, FB and FC in there?

I tried several combinations, it reacts but never 1 in 1

Title: Re: Sysex variables
Post by Breath on Mar 4^th, 2019, 11:24pm

Hi
a CC message is composed of 3 bytes
Status Type Value
The Status is also composed of two parts
eg
B3 07 40

B is CC type of message and the 3 is the channel (as Channel starts at 0 this is Channel 4)
07 the CC type
40 is the value

In MidiOx Data filtering

FA = 3
FB = 07
FC = 40

Data map
Input
CC 07 07 -1 -1 (-1 any value)
Output
sysex F0 47 00 42 48 FA 00 01 17 00 01 00 FC FB F7

Sends out....
F0 47 00 42 48 03 00 01 17 00 01 00 "whatever the value was" 07 F7

Hope this helps.
Royce

Title: Re: Sysex variables
Post by JeanFi on Mar 6^th, 2019, 9:10am

thank you!
i'm going to try that :)

Title: Re: Sysex variables
Post by JeanFi on Mar 18^th, 2019, 1:49pm

FC is the midi channel number, FB is the variable and FA is the number of the controller so the corect mapping to drive the akai S2000 whith controllers is for example : volume

Input
CC 07 07 0 99 (example)
Output
sysex F0 47 00 28 48 FC 00 00 17 00 01 00 FB 00 > 06 F7
this one is ok only for prog 1 .
for the progrm 2 :
F0 47 00 28 48 FC 00 01 17 00 01 00 FB 00 > 06 F7

Title: Re: Sysex variables
Post by Breath on Mar 18^th, 2019, 10:04pm

Hi
first up I don't know why there is a ">" in your sysex messages
F0 47 00 28 48 FC 00 01 17 00 01 00 FB 00 > 06 F7

You can only have data numbers (less than 80 (hex)) and special MidiOx markers FA FB FC between the sysex start (F0) and end (F7)

Is that the problem ?

Royce

Title: Re: Sysex variables
Post by JeanFi on Mar 19^th, 2019, 7:38pm

no, sorry it's 00 to 06, any messages, this byte is the MSB on akai S2000

Title: Re: Sysex variables
Post by Breath on Mar 19^th, 2019, 9:20pm

Yes you are right. FC is the channel and in the case of a CC message FA is the CC type (Data1) and FB is the value (Data2).

Sorry I should have checked at bit closer. Clearly my memory is going 8(

So
F0 47 00 28 48 FC 00 00 17 00 01 00 FB x F7 where x = 0 to 6 is working
but
F0 47 00 28 48 FC 00 01 17 00 01 00 FB x F7 where x = 0 to 6 is not working

It looks like MidiOx is doing what it should, so I guess the second sysex message has a problem.
I tried, but I can't find a sysex specification for the S2000 so I can check what the problem might be.

If you have a link to the spec let me know and I'll have a look.

All the best
Royce

Title: Re: Sysex variables
Post by JeanFi on Mar 19^th, 2019, 9:41pm

Yes the first block works without problems.
The second concerns the program number: if we want to act on the program 1, it is 00 on the program 2, it is 01 ...
The difficulty with the akai s2000 is that depending on the context, it may be the program number or the keygroup number. I have resolved to program only for program 1, keygroup 1 on this machine, otherwise it will take much too much time and it will take a super computer and a super brain that I do not have.
The other difficulty is to assign the values from 0 to 99 of the sampler to controllers that have a 0-127 run, simply using the variable FB, the controller at its last third in the vacuum. It must be tricky for that. Does that tell you something?
I easily found the sysex documentation of akai s2000 on the web.

Title: Re: Sysex variables
Post by Sonus on Mar 22^nd, 2019, 4:28am

The Akai SysEx documentation states that the data portion of any Akai SysEx message must be sent "...in a nibbled form, ie. each data byte is represented by two message bytes: the bottom nibble of the first containing the bottom four bits of the data byte and the bottom nibble of the second containing the top four bits of the data byte."

Negative values are 2's compliment and split into LO HI nibbles:

F0 47 00 28 48 00 00 00 4B 00 01 00 0E 0C F7 0xCE transpose -50
F0 47 00 28 48 00 00 00 4B 00 01 00 0F 0F F7 0xFF transpose -1
F0 47 00 28 48 00 00 00 4B 00 01 00 00 00 F7 0x00 transpose 0
F0 47 00 28 48 00 00 00 4B 00 01 00 01 00 F7 0x01 transpose +1
F0 47 00 28 48 00 00 00 4B 00 01 00 02 03 F7 0x32 transpose +50

... besides 'FB' you would need 'FL' and 'FH' sysex variables.