[Edited 1st June] Introductory overview of the forthcoming Situater
William, fact No 1 about Situater Environment Subsystem (SES):– it's free! Fact No 2:– it fills quite a lot of pages (or "layers") of Logic Pro X's Environment and will work with VEPro locally or remotely (pending full production-standard release of AU3 facilities in Logic), and/or with instruments plugged into Logic's own instrument tracks.
Situater's principal feature is that it 'Supertunes' to orchestral intonation each and every note played live or played back from recorded MIDI. Hearing authentic orchestral intonation means that at every moment the composer can feel more "situated" within the often huge gamut of possible relationships between the notes he's writing - past, current and yet to come. Thus Situater helps to elucidate and perhaps expand the composer's creative horizons and sense of affective narrative and nuances.
SES is essentially aimed at the most intensely creative phases of sketching and writing music, especially where composers might typically prefer using polyphonic "writing instruments" such as piano, all-strings, brass sections, and what have you. Melodies, harmonies and root progressions all spring into vibrant life with Situater.
However, Situater can also be used in developing fully orchestrated mock-ups involving small to moderate production-templates. I'm currently aiming at (subject to change) an operational maximum of 64 MIDI ports. Imagine the impact on film producers and directors when they hear a mock-up in authentic orchestral intonation!
SES depends on virtual instruments being capable of responding accurately to 14-bit MIDI Pitchbend (all VSL instruments have this capability but some others don't - Spitfire, for instance), and being connected into SES. Virtual piano, organ, celesta and other ET-tuned instruments of course can be operated normally alongside SES without any connection to SES.
In operation, the composer selects from a list of user-definable presets - or edits or transposes extempore - which 12 of the 36 total score-notes are to be immediately available when played by his MIDI keyboard, and what type of concert-note "Refinement", if any, is to be applied to any one or more of the currently available score-notes. A score note can be Refined either by shifting it up or down by a syntonic comma, or else by shifting it back to ET when for example a piano playing in ensemble may otherwise be too far out of tune with one or more notes played by orchestral instruments. The only other type of concert-note Refinement used in orchestras but currently unavailable to SES (with my abject apologies to fans of the legendary Pablo Casals) is Expressive Intonation, but may perhaps be included in a future version.
The 12 selected score-notes together with any Refinements, constitute the "Cast" (like a cast of actors on stage at any one time). SES can be "Recast" either by directly editing any note's score-pitch class and/or its Refinement state; by selecting another preset cast; or by automatically transposing the current cast up or down by steps of one or more fifths, anywhere within the maximum range of ±10 fifths from the "natural" signature. Edited casts can be saved as presets at any transposition. The automatic cast-transposition control displays conventional key signature names merely as an aid to navigation and does not impose constraints on what casts the user may construct; however SES warns the user if the current cast has been transposed beyond the note-range of SES.
Well that's my all-too brief and appallingly ragged description. I intend to put together soon a 'brochure' pdf with pictures and stuff that hopefully should serve much better as a preliminary introduction.