I've been playing around with some of the presets in Pianoteq 7. One of the most interesting ones I've found is the C. Bechstein DG Venue preset. It has this wonderful, ethereal quality to it. The sound seems to result mostly from a combination of the mic setup (two omni mics, placed just outside the "box" (room?), set to fairly high volume) and the reverb setup.
I noticed that the mic settings display of one of the mics that are placed near the piano was red (as opposed to gold). Looking at the properties of the mic, the red color seems to indicate that "reversed polarity" is set to "1", which is "ON". So that microphone's polarity is reversed. Of the four microphones used by the mic preset, only one has its polarity reversed.
Does anyone know what reversing a microphone's polarity is supposed to achieve? Search references talk about "full and accurate sound", but in the world of VST's, I'm not sure what that means. When would you not
want full and accurate sound?
Sound is air moving, but the move is not like wind always in one direction: it's pulling and pushing at subsequent times. If you reverse the polarity, you exchange the pulling with the pushing and vice versa. The speed at which the pulling become pushing is loosely speaking the frequency of the sound.
Since that movement take some time to go from one place to another (speed of sound), two microphones at a certain distance could measure pulling and pushing reversed, however that will depend on the frequency and is related to the wavelength.
As somebody said in this thread, that could be much more than you wanted to know (and not enough to answer your question
The point is, to answer this question you need to specify too many details, including the distances between the mics themselves and the soundboard (which is not a point source, if PT is simulating it correctly, and each frequency is generated in a different location of the soundboard). In the end the best way to answer your question is to run some tests, which you can with the PT demo even if you did not purchase the PT version to allow you to do so in production:
1) remove such a red mic and see how the sound changes
2) move such a red mic and see how the sound changes
3) flip the polarity of such a red mic and see how the sound changes
Warning: I've found that these things are usually a huge time sink, so set a timer before if that's a concern to you and stop the experiment when time is over