I noticed with both my old Mission 752Fs, and now my jizzmatic Dynaudios,
that the position for optimum treble for each ear is _extremely_ narrow;
something like +/- 1cm laterally.

It seems not so easy to check vertically, but logically, I think the
situation ought to be the same.

And we're not talking big radiators here; in both cases, the tweeters
are about 2cm - 2.5cm diameter.

I'm always fidgeting to get the clearest, optimum treble. I move slowly
sideways, and suddenly one ear will "click" into a position of very clear,
perfect treble. The trick is to have them both so satisifed at the same
position, and it's _not_ easy!

(The effect arises from the radiation pattern you get when you plot
response versus angle from axis for high frequencies. There's a main
centre lobe which gets narrower as f increases. It also gets narrower
as the diameter of the radiator increases. So it's generally better
to have a smaller diameter tweeter to get a wider main lobe. If my
hazy memories of my acoustics degree serve me correctly.)

It's a pain, though.

Anyone else noticed this ultra-narrow-sweet-spot for high treble with
normal tweeters?


Martin
--
M.A.Poyser Tel.: 07967 110890
Manchester, U.K. http://www.fleetie.demon.co.uk