I'd like to input a slightly different perspective on this issue. I don't have Garritan, but I have several other good vst's, Ravenscroft,Noire, Due, the impressive feebies etc, and an acoustic grand. I've recently been experiencing problems with my hearing. Some hyperacusis, a bit of ageing catching up with me, and some other mysterious medical issues I have yet to determine. This has increased the sensitivity of my hearing at certain frequencies past a point where in the past they wouldn't bother me. I first started noticing certain notes on my acoustic would jar my hearing when playing and now have to wear ear plugs. Coincidently, it is actually around the A5 to C6 range. Playing vst's was less of an issue previously, but I now have the same problem, particularly with the complex harmonics from piano samples, and they are around the same notes....A5 to C6 or so. It seems to happen on almost all my the VST's before I eq them, so along with my acoustic it appears a natural phenomenon, at least to my ears.
I looked at the amplitudes of these notes, and sure enough they are higher around this area than below or above. Fortunately for me, I can EQ them somewhat.
Correct me if I'm wrong, but it appears to be the sample of the natural energy of the strings at these frequencies. I wonder if a range of acoustics exhibit this, or is it my environment for which my piano is situated that is similar to when these top end pianos were sampled for the vst's? Pure speculation on my part, but it certainly has my curiosity up. Perhaps on younger ears, this effect would normally go unnoticed?