I noticed the other day when playing this track, a 'buzzing' type of sound coming from the tweaters of my Paradigm S8 speakers, this was being caused by the bright flute sound on this track. I proceeded to remove the grilles on both speakers, I noticed the tweaters themselves were moving when the flute played. The movement is very subtle but it's there, it looks like one side of the tweaters lifts off a little letting air out. I took the same recording to my other room where I have a pair of S2's, I noticed the same bright sound with this track, though not as bad as with my S8's. I also removed the grilles and saw movement on the speakers' tweaters though almost non-existant. Anyway, I guess my question is, is this normal or is this a design problem with the Paradigm tweaters? To put in perspective this particular track is almost unberable to hear, is that bad, with either the S8's or the S2's. I have noticed similar type of 'tweater buzzing' with older recordings, like the Billie Holiday's Ultimate Collection CD's, some of the hissing and cracking sounds of these original recording produce this 'buzzin' bright sound from the tweaters and makes it a very unpleasant listening experience. Thanks a lot any feedback.
I tried this cut just now with both the B&W N802Ds and the Revel Studios and heard, of course, the flute along with the noise of AM's breath blowing across the hole in the mouthpiece and, also, his inspirations. At high levels, this was very noticeable but not annoying. I did not see any tweeter movement.
That you find such sounds, and others mentioned, unbearable or unpleasant may have to do with the balances you are getting from your system and room acoustics. This is treatable.
On the other hand, the asymmetric movement you describe for the tweeter in one of your S8s is suggestive of a defective driver since the tweeter should move, if at all discernibly, forward and back and without any other modes. If you reverse channels (at the preamp or amp) and the problem remains with that original S8, you need it serviced.
The cause could be almost anything, from amp instability to a leak from the MR/LF enclosure to random failure. Get it looked at.
Slight on-axis movement may be observed in some tweeters depending on their resonant frequency, the crossover feeding them and the signal content. I did not see any in my tweeters (I could feel it, though) but that's not here or there. It is the asymmetric movement of one of your tweeters that is of concern.