I'm curious about the details of matching synchron percussion and synchron MIR room pack.
I think your choice of piece is very challenging for the mixing task. The percussion instrumentation, including piano, really exposes the qualities of reverb of synchron percussion library and also in the MIR room pack, and the short tails of the synchron venue make it even harder to make that match. I imagine that if it's possible to make the piano match very closely the sound of the synchron percussion library, then similar mixing approach would also work well for other instruments in MIR, at least woodwinds and strings, for the purpose of matching to synchron percussion.
So having said that, some concrete questions and thoughts:
(1) Can you please describe more about how you have mixed the pianos so far, and what have you tried so far in an attempt to match the sound of synchron percussion library?
(2) Which microphone positions / mix have you used for synchron percussion in this piece?
Here's the way I am hearing the mix currently. I feel like the pianos sound great by themselves, but they seem to be in a different "space" than the synchron percussion library. Compared to the sound of synchron percussion, it feels that the piano has too much "solid presence" in the tone, and it sounds too much like a coincident microhpone technique, or panning the two pianos, as opposed to having them be spatially positioned. Which does sound great then only the pianos are playing. but with the xylophone or timpani along with, suddenly the piano mix sounds too up-front and not spacious in the correct way.
I would be very interested to know if any of these ideas actually makes an improvement or not, if you have time to try them. I don't (yet) have synchron percussion or synchron MIR roompack yet to try myself. But I'm very excited to buy them when I can.
Possibility 1 - is it possible the pianos sound more like synchron percussion if we used a reduced dry mix / increased wet mix?
Possibility 2 - Do you have the "distance dependent scaling" turn on, in your MIR mix? What about "simulate air absorption"? I wonder if that would help the fit.
Possibility 3 - Would it make any difference to move the pianos further from the virtual microphones in the MIR venue?
Possibility 4 - The panning issue is a big one that breaks the immersion between piano and synchron percussion. In this kind of studio space, the percieved position of an instrument is actually not so much caused by the volume level difference between L and R channels. In fact, by the meter, the L and R levels may not be much different at all, even though we would still perceive some spatial positioning of the instrument.
Instead, I think the perceived spatial position in the synchron percussion library is more attributed to the reverb of the stage itself, the early reflections, and even just the phase difference of the same sound arriving at slightly different times on each mic (i.e. 0.1 - 0.2 milliseconds different perhaps? it's possible to do some rough geometry estimates with the speed of sound to get a good number. but it's not just the distance between the two mics, it will be less delay than that).
So maybe it's worth a try to keep the pianos more centered across the stereo field, in terms of their level difference between L and R, and instead to further accentuate their side positioning by using a sub-millisecond phase difference between L and R channels, like 0.1 milliseconds or even less. This can be done with the Matrix Mixer FX. And, maybe even emulating a deca tree by having two mixer channels of audio for each piano, one channel for L and R, another channel for C, with levels and phase delays adjusted to simulate the sound coming from a specific location on the stage.
Looking forward to hearing your thoughts!