I think I want to build a set of horns...

[h2oTom]

The output impedance is often specified by the damping factor (a quite confusing term).

A high output impedance amplifier has a low damping factor.

Well that's a LOT simpler and easier to understand. Dave, you're awesome! (internet high five)

I think I may just go with the FH3 and the suggested drivers.

Thanks!
Tom

 

[chrisb]

I think what Dave has in mind is either something along the lines of an old school valve type design, or adding some series resistance to SS design to reduce damping factor. GM or Scott could expound far more eloquently and reference which particular specs of the total T/S parameters are in play.

FWIW, I have a combination of SS and valve amps and an array of FR drivers to rotate in 2 different rooms / systems.

2A3 and EL34 SE - approx 3.5 & 7? watts respectively
EL84 P/P pentode -approx 12 W?


TPA3116 digital amp
Onkyo TX NR something or other 7.2 surround receiver - must be all digital as well? but frankly I don't care one way or the other - it sounds fine to me.

The FE126 in FH3 sound "best" with the EL34 in terms of "warmth and body" - two very technical engineering terms I learned from Scott - all of the Mark Audio drivers from CHBW70 through Alpair 10P, as well as the FF85, 125 and 165WK that I've heard "play nice" with any of the amp types, although the Onkyo certainly offers the most system power - 7 x 70w if you can find convenient locations for the 4 surround channel enclosures.

The FF125WK works in the FH3, and if you like the Fostex sound, I'd suggest it over the 126En or 166En for a room this size.

 

[talaerts]

Hey, I've been enthralled with horns since I heard a pair as a kid back in the 80s.

I'd really like to build a pair and I'm considering going with a pair of the Fostex FE166En and using the fostex suggested plans. I've built some subwoofer enclosures in the past, but I've never attempted anything on this scale.

If you get the local wood supplier to cut the wood (many think that marine grade multiplex plywood will sound best) for you according to the cutting diagram of the Fostex plan, perhaps even including the round speaker hole, then it is really just a matter of glueing everything together with lots of clamps.
I am not sure if you'd need to add the strange ribs at the back. I think they are there to increase the stiffness but it will probably not make much of a difference.