Since just before my move south the smoothness of the treble from my 4Pi set-up has gone south. It seemed to coincide with a transformer upgrade to my 45 amp but amp substitution eliminated that. Could have been my pre-amp but replacing it with a passive was no cure. Turning to the crossover and making adjustments hasn't helped, either. It's not the room because the symptom is the same in old room and new. Lastly, the problem is the same with either CD or vinyl as a source.

What it is: on loud dynamic peaks like female voice or saxophone in the upper register there is a sharp, brittle sound to the leading edge of the note. Kind of like that painful ringing you hear when a dog barks in an enclosed space, for lack of a better simile. Somewhere around "F" above middle "C".

The problem is worse with the speakers off-axis, not toed-in and against the front wall. Somewhat better with them moved into the room about 3'and better yet with them out into the room and toed-in almost facing the listener. Still apparent and annoying, however.

The Vifa DX-25 tweeter, 2Pi-like speakers don't exhibit the issue.

The SIQ (Speakers In Question) are 16ohm JBL2226J and 8ohm B&C DE-250 with the standard 1600Hz Theatre 4 Pi crossover with R1 = 30ohms, R2 = 15ohms and a .33 Kimber Kable capacitor.

What's a boy to do?