My New Small Speakers
Here's what I'm planing on using in my new pair of speakers.
I just bought a pair of Focal Tc120Td Titanium dome tweeters with the titanium
dioxide coating.
I got the pair used for $60! They appear to be in perfect condition, except for
a tiny chip
on one of the magnets. The Fs of these tweeters is 693.9 Hz, so I
planned
on a crossover of at least 2775.6 Hz. This limited the woofers I could use,
since not many woofers
under 8 inches can play from at least 70 Hz to 2775.6 Hz. After looking at many
woofers,
I decided on an Audax TPX 6.5 inch woofer (I haven't bought them yet, this might change). It only plays down to 74 Hz
in a Qtc .707 sealed box, but that's OK, since they will be crossed over to my Swan's
at 100 Hz, with a 2nd order slope. They play up to ~4000 Hz (I don't have my product literature, so
I don't have the exact number.), but have a slightly rising response up untill then.
30º off axis, however, is fairly flat to 3000 Hz, with a roll-off then. So, I'll place them pointing straight ahead,
not toed in, so I'm sitting 30º off axis. I'm not sure what effect lobing has on dispersion, I might have to correct for that; I have to go over that section in the LDC some more.
I am going to put a notch filter on the tweeter, a notch and an impedance EQ on the woofer, and a notch on my Swan 305 subwoofers.
The crossovers in the system will be 2nd order Linkwitz-Riley's. The sub will have a 12 db/octave highpass subsonic filter at around 18 Hz.
I am going to use Solen polypropeleyne caps, or Bennic electrolitic caps, for the large values. I will use either Solen coils, or I'll wind my own.
I'm going to buy the most neutral speaker wire I can get for a reasonable price for internal wiring.
©1997 Sean Cunningham
