Can I change the MIDI channel in the middle of reading on a track ? I have to send some notes to a different instance of Kontakt.
Can you set it up like it is two instruments first, then in set-up mode, drag and drop one of the instrument to the other, like you would when setting up for the player to change instruments. Try that? For example, I have flute 2 doubling picc quite often, and that track then can play from two different instances.
Good idea. I’m trying. Thank you.
In addition to the above suggestion, a Playback Technique can be used to trigger a channel change. Just add the channel change definition in your Expression Map that you are using for that instrument. Another way would be to put the music you want to play back differently in a different voice, and then assign a different channel to that voice in Play mode.
Switching channel is one thing, but to a different instance of Kontakt…? (as requested by OP)
In play mode, you can create as many instances of a VST as you want, and manually assign different voices on each staff to them in any way you wish.
Of course you then lose the benefit of Dorico’s automatic VST assignment for playback, unless you set up your own playback templates, and if you create your own templates for this sort of thing you probably have to accept the overhead (in memory or CPU usage) of using more instances of VSTs than you really need.
Of course, it should work. But I don’t understand Dorico’s Expression map options between relative channel and absolute channel. I searched and I can’t find a reference to this. Do you know the difference?
In my case, which here is a simple violin and cello duo (with the Sacconi Quartet from Spitfire audio), I want to keep only one staff per instrument. Now, I have to send each one sometimes in a special patches intended for very fast short notes. If I can change channels by modifying the map expression, I keep only one instance of Kontakt per instrument, but with two patches, each of which has its own channel. I can even put the two violin patches and the two cello patches in one instance, with 4 channels, that’s no problem, as you know. In the case of a large ensemble or a full orchestra, I don’t know what I would do. This will be my next problem!
“Relative” and “Absolute” in this case refer to whether or not you are specifying the actual channel number (which is “Absolute”) or the number of channels away from the current channel that the new channel should be (which is “Relative”). So if you are currently using channel 4 (say) and you specify an absolute channel change to channel 1, Dorico will switch to channel 1. With a relative change, Dorico will switch to channel 5 (or to channel 3 if you specify a relative change of -1).
just to clearify what I wrote above… if you have say 2 instances of Kontakt in the VST rack (we call them KA and KB), you cannot, as far as I can determine, switch, by means of an Expression Map in KA, to a Midi Channel in KB. (Again, that’s how I interpreted the OP question 
)
To expand on Daniel’s answer, there’s a specific use case that Relative Channel Switches were intended for. Suppose you have a library (Iconica, say) that has techniques in different programs such that in channel 1 you have arco and pizz, in channel 2 staccato and legato and channel 3 for con sord. All the string programs have the same keyswitches and techniques. You have 16 channels available so you can load one instance up with 3 channels each for violin 1, violin 2, cello, bass. Rather than creating an expression map that uses the absolute channels 1, 2 and 3, you can use relative channel switches. So the expression map looks like this:
nat relative change 0 + keyswitch
pizz relative change 0 + keyswitch
stacc relative change 1 + keyswitch
legato relative change 1 + keyswitch
mute relative change 2 + keyswitch
and in HSSE you have the following loaded:
1 Violin 1 arco/pizz
2 Violin 1 stacc/leg
3 Violin 1 legato/mute
4 Violin 2 arco/pizz
5 Violin 2 stacc/leg
6 Violin 2 legato/mute
7 Viola arco/pizz
8 Viola stacc/leg
…
In the track headers you route Violin 1 to channel 1, violin 2 to channel 4, viola to channel 7. In the Endpoint Setup Dialog you set your expression map for channels 1, 4, 7, 10. The relative change is added to the ‘base’ channel. So in summary, the relative changes just allow you to use the expression map multiple times in the same instance of the plugin - it just shifts relative to the starting channel. And a relative change of 0 always takes you back to the base channel.
Thanks Daniel, this is very logical (and useful). I don’t know why, but I hadn’t found yours on this. It would be good to indicate this in the next manual if possible. For now, it is written only that: Add Absolute Channel Change Action: Adds an absolute channel change action with default settings. Add Relative Channel Change Action: Adds a relative channel change action with default settings. [/ I]
Yes, channel change and change of instance is different. For the change of instance, the solution is probably what RWW suggests below:
Can you set it up like it is two instruments first, then in set-up mode, drag and drop one of the instrument to the other, like you would when setting up for the player to change instruments.
Thanks Paul. Keep safe. This kind of information should be able to be compiled somewhere, perhaps in an advanced appendix to the manual (no manual does that I think, but it would be useful).
So I can also deduce that by means of the relative channels one can go from one instance to another in the case of a single instrument? I may be reading poorly. My English is sometimes like a cracked cymbal.
No, you can’t go from one plugin to another using relative channels - you can only change the channel for the current device.
Thanks Paul. My mistake.
Subsidiary question: I have just modified the Expressio map on a violin, as a test, by requesting a change of channel for the pizzicato technique. It works perfectly. But we no longer leave the pizzicato, then, with ordinary techniques or by mentioning “Nat.”. So, in the expression map, should each articulation be added its channel number? Is there another method?
If you are using articulations that are on different channels then every entry in the expression map needs to have a channel change switch to tell Dorico which channel to use.
If you don’t want another staff cluttering up the view in Galley, the voice solution allows you to change instances as well.
If I take this simple example in two voices with voice colors showing:
I can assign “Up-stem Voice 1” a Garritan CFX Concert Grand sample,
and “Down-stem Voice 1” a Vienna Synchron Piano sample.
Playback then switches between the two instruments. I don’t have Kontakt, but I assume if I can easily mix and match completely different VST Instruments, you should be able to do this with instances of Kontakt too.
Wow! That’s what you said below, but I understand better now. Thank you very much.
I would like to thank everyone for that support. The Dorico community is really active and helpful. It’s beautiful to see.