Help with Akai Synthstation 25 midi cc to program change?

Hi xylograph,

You essentially use the technique described here but the rules will be different.

The 8 buttons on the SS25 have the following CC codes in hex:

DRUMS   50
SYNTH 1 53
SYNTH 2 51
SYNTH 3 52
PREV    55
NEXT    54
DOWN    56
UP      57

Note that those last two will also adjust the octave of the notes that the SS25 sends (more on this later).

To simply map one of the buttons to a program change, some example rules would be:

BX 50 7F = CX 00 # DRUMS -> PC 1
BX 53 7F = CX 01 # SYNTH1 -> PC 2
BX 51 7F = CX 02 # SYNTH 2 -> PC3

You can also change the MIDI channel of the SS25 events with the buttons (use PREV/NEXT and not UP/DOWN since the latter changes the internal note octave) using 16 (if you want all 16 channels) scenes that you use the PREV/NEXT CC events to switch scenes in round robin and install a mapping. There are some other posts here about doing round robin scene changes, but essentially you make 16 separate scenes with slightly differing sets of rules:

scene 000 (channel 1)

BX 55 7F = CF 0F +C # switch to scene 015 on prev
BX 54 7F = CF 01 +C # switch to scene 001 on next
XX = X0 # force to MIDI channel 1

Scene 001 (channel 2)

BX 55 7F = CF 00 +C # switch to scene 000 on prev
BX 54 7F = CF 02 +C # switch to scene 002 on next
XX = X1 # force to MIDI channel 2

... and so on until you get to the final scene 0015 (channel 16)

BX 55 7F = CF 0E +C # switch to scene 014 on prev
BX 54 7F = CF 00 +C # switch to scene 000 on next
XX = XF # force to MIDI channel 16

I have highlighted the numbers you need to change for each scene in red. This assumes that the MidiBridge Scene Channel is set to 16. Luckily you only need to do this once.

Hope that helps (and hopefully I got all the detail above correct!)

Regards, Nic.

Hi xylograph,

Yes, sorry the Stream Byter isn't that smart; it doesn't have any sort of basic maths, so incrementing a byte isn't (currently) possible, and I do not recommend creating 128 scenes.

One option would be to set the program change by holding down one of the buttons and then pressing one of the note keys to determine which program change. You'd only need two scenes.

First scene switches to second scene when button held down
Second scene maps note to program change and switches back to first scene on release

Might not play well with the channel round-robin scenes though.

Probably quite tricky really.

Regards, Nic.

Hi again Nic,

When trying your midi channel formula with all the different scenes it changes/switches the program on the given channel only instead?
There is no scene switching going on.. Did I forgot something here?

Thanks

Forgot to set scene channel to 16 !
Everything is working now

Thanks Nic !

Hi xylograph,

Another curve ball!

You can probably do this with 1 button (maybe 2 if enough permutations) but will probably conflict with your channel selection strategy. Not only is there no maths in the Stream Byter the logic is limited to simple pattern matching really.

However, here is how it can be done in isolation. Again using scenes (just 2) and we'll toggle the DRUMS button

Scene 000

BX 50 00 = XX +B # always block off
BX 50 = CF 01 +C # switch to scene 001

Scene 001

BX 50 00 = XX +B # always block off
BX 50 = CF 00 +C # switch to scene 000
BX 50 = XX XX 7F # rewrite on to off

Regards, Nic.