For attaining best instrumental realism and most convincing spatialisation in the mix, the Dimension collection is I believe still unsurpassed in the market. And realising this wonderful potential is much easier, more flexible and convenient with the Synchronised version, partly and importantly because the Synchron Player can stream up to 18 concurrent mono audio channels.
I've been getting superbly convincing results with Sy Dim Brass, and more recently, having bought the full Sy Dim.Strings 1 library, I'm over the moon at having 32 string players each positioned precisely where I want them in a stunningly convincing stereo field - even without a drop of reverb anywhere in the chain.
I find azimuth positioning most flexible, easy and realistic when dry mono channels are individually positioned in the stereo sound stage using binaural panning. Then adding reverb is also easy peasy and super flexible. LPX users have long had the built-in Binaural panner on each mixer channel, but there are several plugins that can do it too.
Seating - theory v practice
For many years I thought spatialising a simulated orchestra was about accurately modelling the players' seating positions on stage. Hahaha, nope - that's not how sound recording and mix engineers typically present orchestral performances to us. Now I'm arranging most players along a single-line semicircular stereo arc of no more than about ±60º total azimuth spread, and my favourite listening position is a few metres above and behind the conductor.
Why not go beyond ±60º? Because it tends to be disturbing for the listener, that's why not. It seems there's an instinct in us that makes us want to turn our head towards a side-only sound, probably so we can get a decent azimuth and distance fix on it; but with headphones or stereo speakers of course this can't work. Hence more or less one-sided sounds are likely to be an unwelcome nagging disturbance.
In simulating near/far relationships, only a few significant cases need be of concern. For example, for timps, perc., harps and heavy brass, added reverb can be set wetter and with less pre-delay, to help place them farther back in the mix more convincingly than with level alone. Also in these 'far' cases a gentle 6dB/octave EQ roll off at the HF end can help reduce 'presence'. Most other sections can be treated as 'near' and can compete for listeners' attention at or fairly close to the front stereo arc of the mix.
Despite the miraculous effectiveness of today's spatialisation technology, it's always well worth checking and dynamically balancing your whole mix in mono, rather than depending on stereo width to try to relieve problems of congestion and/or masking in a busy mix.
'Tell me lies, tell me sweet little lies'
Notice how microphones are deployed in recorded concerts: one can often see high boom stands with mics aimed down at instrument sections, and even mics suspended high and hanging straight down above sections. Recording and mixing a performance is less about putting the listener in any particular seat in the auditorium, more about presenting balanced contributions of all the players, without those players who are seated behind others being needlessly somewhat masked.
The intentional result of sound recording, mixing and mastering, like pro photography, is hardly ever completely honest and truthful. If acoustical truth is what listeners prefer, then a Neumann artificial head-with-torso sat somewhere in the auditorium would provide the only 2 microphones required. Now in the case of film scores - well, just lol at the idea of truthfulness there.
There's always been a substantial overlap between music and the dramatic arts, carrying with it countless implications in terms of deception, pretence, conjuring tricks, suspension of disbelief, etc etc - ignore that at your peril.
Routing and processing
In reality, beyond a few metres distance the sound of most types of individual instrument has no dry width of course. Hence it's perfectly valid to start out with dry mono sample sources feeding one dry mono mixer channel per instrument. Two independent mono channels can be streamed from each of Synchron mixer's 2-channel outputs, simply by setting the Balance (not the Power Pan!) control hard left and hard right respectively on the two instrument feeds to each Synchron mixer output pair. In this way, up to 18 mono channels can be streamed simultaneously from each Sy Player plugin.
Having received and organised these multiple mono streams in VEPro or your DAW, the general azimuth direction and spread of each multi-player section (e.g. Vn1, Vn2, Va, Horns, etc) can be set up with binaural mono-to-stereo panners - preferably one per instrument. Sections can be made as wide as is sensible for a reasonable representation of actual stage seatings, given the preferred listening distance. This is simply a matter of choosing the size of angle that separates each instrument's dry line of azimuth as set by its individual binaural panner.
For example I find that within a section, separating each instrument from its closest neighbour by typically about 5º to 8º gives excellent results for my 'helicopter' listening position. Note that straight ahead, ours ears can resolve azimuth differences of about 1º, whereas more towards the sides, resolution gradually degrades down to around 16º.
The beauty of binaural panning is that our ears easily and spontaneously detect the average, median or general azimuth direction of each section's dry stereo spread, whilst maintaining a sense of how wide each section is. Hence adjacent sections can be overlapping. So it's not necessary to cram all individual instruments tightly together across the stereo arc in an attempt to give each its own exclusive azimuth angle.
In short, setting azimuth binaurally on each of many individual dry mono instrument channels gives unbeatably convincing and vivid stereo positioning, and provides a clear, firm foundation ready for reverb.
Sample libraries built from recordings of ensembles are a very different matter. In this case stereo information must come from close stereo and ambient stereo mics, and/or from added spatialisation reverbs - which is where MIR excels. But that's another story and no doubt I'll be spamming the forum enthusiastically about that when I've bought Synchron Strings.