Specify instrument for channels on two different places

Hi All

What is the purpose that we can set the instrument for the channel on two different places. See image (vst_instruments : middle and right icon of the three).
vst_instruments.png
Once inside the HALion plugin (middle icon) and on another windows (right icon - see other image).
Regardless of what i set on the other window, it’s being ignored and i only hear the one set in HALion plugin.
dorico_instrument_per_channel.png
I somehow don’t understand the concept of specifying the instrument for each voice on two places here. Any hint appreciated.

Thanks
Daniel

Your 2nd picture is where you set or change the expression maps for the midi channels, not the channels themselves…

I have to admin not to be very experienced with more professional notations software, so Expression Maps are new to me, hmm.

Am i right with: Expressions Maps are where to set parameters to more technical aspects on how the notes are interpreted/played from a virtual instrument?

So when i set the voice to Violin, but want it to be played more like a flute (no-one would do that i guess) then i would set flute as the expression map.

Choosing a flute VST Expression Map for a violin patch won’t make the violin sound more like a flute: rather, it means that when you write a given playing technique in the score, when Dorico tries to look up what keyswitch or MIDI controller should be employed to produce that playing technique, it will get the wrong answer, or indeed no answer – for example, writing “pizz.” on a violin staff would result in Dorico being unable to find out which keyswitch to play to produce the right sound, because the flute Expression Map won’t define anything for a pizzicato effect (since flutes can’t be plucked, of course).

A virtual instruments is generally put together so that it contains several performance styles in the same file, e.g. sustain, legato, marcato, staccato etc. These are typically referred to as Articulations or Playing techniques, and typically about an octave of the midi compass (which is from 0 to 127, with 60 being middle C on the piano), well outside the sounding range of the instrument itself, is set aside to be used as switches for selecting these articulations. E.g. pressing the lowest C will switch to staccato, the lowest C# to legato etc.etc. Which keys to press (and what addtional data to provide) varies greatly between manufacturerers, therefore dedicated expression maps are needed. This whole procedure is commonly known as Key Switching.

The job of the expression map (A Steinberg term of Cubase hertiage) is simply to translate the instructions in your score to the correct switch on the present instrument. Dorico e.g. will typically understand slurs, staccato dots, maracti and accents, tremolo etc. and also a growing number of instructions such as spiccato, sul ponticello etc.

Thanks so much for this in depth background info about how this is working.

hmm, but wouldn’t it be then much easier to bind an expression map together with the instrument assigned to a player in the setup page, so it would not matter on which midi channel it is finally using during playback ?

It might be easier, but it’s too restrictive. For example, one staff on the score might need several MIDI channels to load the sounds for different performance techniques - e.g. you might have a single “violin” staff in the score using the arco sounds from one sample library, and the pizzicato sounds from a completely different library, that only works with a different VST sample player which therefore must be on a different MIDI channel.

Of course if you only use the Dorico-supplied sounds, that’s probably not relevant for you, but it would be for other users.

Yes agree, it’s more flexible that way.
Thank you all