We're kind of veering off track from my original post, but it has started an interesting conversation none the less and I always enjoy discussions about what can be done to improve the sound and realism.
First I will just say what I mostly mean by 'it sounds better' is I just like the pitch better, not so much that it made some big change in the sound quality, I'd say it really didn't do much of anything there. So, sorry for any confusion that may have caused.
I took some time this morning to play the Dingelsteadt at both its 'as is out of the box' tuning and at -125 cents, I played the same exact songs just to make some comparisons. First off I will say regardless of the set I own, there is
some of what Jiri describes as harmonic distortion, aliasing, or as others have referenced to as intermodulation distortion, or whatever, etc. The Dingelsteadt displays some of this as well in certain areas, in particular in the highs which I've also noticed on other sets as well. I wouldn't necessarily call it an 'audio' distortion like the audio is getting fuzzy, to my ears it's more of a clashing of harmonics, like beating notes or somewhat of a grating sound the opposing notes produce, and again it's more prominent in certain higher pitched notes when played against or along side of each other. I took note in the passages of the song I played where this more so jumps out, then re-tuned, played the same passage and sure enough the same thing happened in the same spot. I wouldn't say it was any worse or had been exaggerated, just that it was still there and overall the instrument sounds as good at -125 tuning as it does at stock tuning.
Interesting theory: Maybe this holds water, maybe it doesn't, but perhaps I have discovered a way to minimize the harmonic distortion problem. I have posted here numerous times regarding both speaker placement / positioning and audio routing schemes, in particular various rank routing schemes to speaker pairs and have reported the results. I have found that sending ranks to speaker pairs based on their 'like sounding or in the same family of sounding' has produced the best results, at least for me. Something I also noted in my experiments was the dramatic change in clarity and the lessening of harmonic distortion depending on which routing scheme I used. Highs in particular, especially mixtures can be tricky and it takes some experimenting to figure out where best they fit in the speaker pairs, but I can say I've eliminated the harmonic distortion effect by a good 90%, not 100% but with an additional few pairs of speakers on separate channels to further divvy things up, who knows? Unfortunately I only have 10 channels total to work with. Perhaps in all of this I've discovered a way of getting away with more than expected?
Marc