[2litre]

Hi All,
Well I modified them, 3 times.

1- I didn't like the 6.5/tweeter combo after listening to it for awhile. In keeping with the rough and cheap theme I replaced them with a pair of long forgotten .49c PE closeout NSB's. Much sharper presentation and I gained, roughly, an additional 6K Hz on the top end over the 6.5". Now they go out =/-3db to just over 12.5kHz.

2- I also pulled the high pass down from 360Hz to 257Hz. I'm sure I used fuzzy logic on that decision but I happened to be reading about BSC and used Martins simple formula of 4560/(baffle width in inches) to determine the baffles F3 of @253Hz. So to keep the new component required count to a minimum I used spare 7mh inductors as the base for a 257Hz 2nd order XO point. I had to buy caps.

3- Doug and I did an A/B comparison between one panel with an FR125S as the top driver and a panel with an NSB as the top driver. Absolutely not as one would expect! The NSB panel sounded more open, crisper. The FR125S panel sounded....muffled, restrained. So we decided to eliminate 'the other part of the equation' by disconnecting the bass driver so we could concentrate on the presentation of the full ranges. Still the same thing. The NSB's sounded better in my opinion. When paired back with the bass units you could tell the differences in efficiency of the full ranges compared to the bass driver. The NSB, being about 3db more efficient than the FR125S, is spot on with the bass driver. With the FR125 the combo is bass heavy.

So that's where we are now. $40 (and double that in luck) has given me some nice knock about OB's.

R/

Jim

[panomaniac]

Great looking project!  Glad to hear that you got it going and sounding good.

My 1st OB attempt was with 12" CTS alnico drivers, maybe the same model.  They came from an old Magnavox console and were paired with metal Foster horns.
The OB I built sounded awful, way too bright, no bass at all.  But the baffle was maybe too small and the crossover was all wrong.
See the photos below.

Though I dumped the baffles, I still have the drivers.  When my new Woofer Tester 3 form Parts Express gets here, I'll measure the T/S parameters and the impedance curves and post here.  Been thinking about getting them back up and running.

View from behind:



Hey!  What kind of woofer is that??

[2litre]

panomaniac,
I still have a pair of those horns. They were mated with my CTS 15's. Unfortunately I chucked the original XO from them otherwise I woud just replicate it with new components and see how they all sounded in OB.

Your set up looked very nice.
Hey, those drivers were once paired up and once you find the T/S on them all I bet you can easily pair them again with a modern XO. I'm sure they'll sound nice.
IIRC the original XO was a simple one, a small inductor, a cap and a resistor. I guess that made it 1st order with a bit of attenuation for the horn.

I'd like to hear your experience with the PE woofer tester. Been eyeballing that myself.

R/

Jim

[panomaniac]

Hi Jim.

I do have the original crossover for my set.  1 cap, 1 coil, 1 resistor.  Looks like a 2nd order with attenuation on the horn and the woofer runs fullrange.

As soon as I get a chance, I'll run the woofer tester on the drivers.  Should be fun to see if we can come up with a decent crossover.