Sean and all- I just wanted to listen carefully again to confirm what I already had perceived: Listening to the recording at a lower volume, at least on the SET/horn system at work, I really can't tell that there is any distortion on those same high notes that would otherwise be quite obvious at higher volumes. On some I can hear it, but I'm wondering if that is is fed by my expectations. On most I cannot hear any distortion listening around 80db+ (very moderate level for a large space). I do recall listening to the same CD on my friends system with a Unico Unison (80W hybrid amp) and having the similar objections which I attributed to the SS rearing it's ugly head. So I'm thinking that it is the recording and not the gear since it occurs on three entirely different systems. Weird that it doesn't occur to me at the lower volumes though. Perhaps I need to get my hearing checked.
As far as the recording techniques, unfortunately there is no notation as to how it is recorded (there are extensive multi-lingual notes relating to the history of the piece and the proposal for the performance itself). The CD is made in Austria by Sony and is not marked with the typical acronym for how it was produced (ie AAD, DDD, etc.). I checked another of box-set I have on the AllaVox label of Jordi Savall performing solo. Again, no references to recording techniques and lots of history. On that recording, which is also outstanding, I believe they must have had the mics very close to the performers as the breathing is very pronounced. Almost to the point of distraction, but ultimately the music is so powerful, and the presence of the instrument(s) so remarkable, that I it just enhances the intimacy. I mention it because it definitely occurs to me as a unique recording in that respect.
I'd be curious to hear from anyone else who's heard the recording in question (Sibil-La) and could comment directly to having heard this.
Thanks to all who posted for taking the time to respond.
Marco