I've seen one in the wild, in a thrift store.
Pretty sure it was the exact same one, but it's been some time so I cannot be 1000% certain -- and that's not the highest res picture either. Anyhow, the driver I saw was essentially an early version of the FX200 without the JBL D123A style 'aquaplast' coating. The frame was cast aluminum. It was in a 2 way with a fostex/foster ribbon tweeter. I should've/would've bought them, but I already had about 8 pairs of speakers at the time...
That said, it's closest living relative would be the FF225WK.
Pretty sure it was the exact same one, but it's been some time so I cannot be 1000% certain -- and that's not the highest res picture either. Anyhow, the driver I saw was essentially an early version of the FX200 without the JBL D123A style 'aquaplast' coating. The frame was cast aluminum. It was in a 2 way with a fostex/foster ribbon tweeter. I should've/would've bought them, but I already had about 8 pairs of speakers at the time...
That said, it's closest living relative would be the FF225WK.
that does look like a very nice way to employ your FF225WK - lets see if we can find it in catalogs online
probably not in this one http://www.preservationsound.com/wp-content/uploads/2013/09/Fostex_SR_1981.pdf
probably not in this one http://www.preservationsound.com/wp-content/uploads/2013/09/Fostex_SR_1981.pdf
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I'm trying to work out such an arrangement for FF225WK. According to Hornresp, a 15cm long horn with a 1600cm^2 mouth does a fine enough job of giving a small boost around 200Hz-500Hz. A 40L box tuned a bit high, around 50-55Hz, raises up the midbass to keep up with the horn gain. This should balance out nicely against the progressively hotter response above ~1.5kHz, possibly creating a mild "BBC-plateau" in the midrange. Baffle-step should not be much of a problem then, with room placement and drive impedance the main factors to consider.
I have a rough sketch and the box is 26" high, 15.5" wide and 12.5" deep. It could probably be used fullrange with FT17H brough-in wherever response falls-off, or be used as a midbass box with my 700Hz petal tractrix horn on top.
The above Fostex enclosure appears to have slightly curved upper and lower horn panel. It seems all flat walls would have a bit of a lower Q, which would better suit my present arrangement.
I have a rough sketch and the box is 26" high, 15.5" wide and 12.5" deep. It could probably be used fullrange with FT17H brough-in wherever response falls-off, or be used as a midbass box with my 700Hz petal tractrix horn on top.
The above Fostex enclosure appears to have slightly curved upper and lower horn panel. It seems all flat walls would have a bit of a lower Q, which would better suit my present arrangement.
hey IG81 - have you figured a radius for the top bottom plate's curve? - this should also be fun fullrange with FE206EN - its scary how fast time slipped away from 1981 til now 😱
My horn's latest dimensions:
Driver mounting board, ~throat area = 8.25" x 8.25"
Mouth area = 12.5" x 20"
Axial length = 6"
If the top and bottom horn walls are to be curved, the radius would be 15". It should not be too hard bending/gluing/nailing a thin or kerfed plywood to conform to that. OTOH I remember what a hard time that SK8 curved reflector gave me. 🙂
FE206En would work, but preferably with a smaller back chamber, somewhat higher tuning and a couple Ohm of drive impedance. Various pro 8" drivers from Eminence or B&C would make a great and compact midbass/midrange bin in such an arrangement, making close to 100dB/W in 2Pi space from ~90Hz-100Hz and up.
Driver mounting board, ~throat area = 8.25" x 8.25"
Mouth area = 12.5" x 20"
Axial length = 6"
If the top and bottom horn walls are to be curved, the radius would be 15". It should not be too hard bending/gluing/nailing a thin or kerfed plywood to conform to that. OTOH I remember what a hard time that SK8 curved reflector gave me. 🙂
FE206En would work, but preferably with a smaller back chamber, somewhat higher tuning and a couple Ohm of drive impedance. Various pro 8" drivers from Eminence or B&C would make a great and compact midbass/midrange bin in such an arrangement, making close to 100dB/W in 2Pi space from ~90Hz-100Hz and up.
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I have several single-ended tube amps which would effectively raise qes. Do you think those sidewalls are parallel? (looks like it) A foam board build could work for a prototype. Beta8cx would probably work well enough with ASD1001, etc.
My estimates are not so much the actual dimensions of the Fostex box, but what works in HR for FF225WK. Slightly hard to say if the sidewalls are parallel, with one being hidden from view, but I've worked out my enclosure for them to flare out (conically ~20° per side) from 8.25" to 12.5". Some standing waves may rear their ugly heads if parallel, though it would greatly simplify construction.
I now have a workshop at my new place and may yet build this come spring - we've been into a deep freeze as of late. Yesterday's high of -5°C truly was a relief. Not that I need more speakers, but I'm itching for a project and do have some driver laying around.
I now have a workshop at my new place and may yet build this come spring - we've been into a deep freeze as of late. Yesterday's high of -5°C truly was a relief. Not that I need more speakers, but I'm itching for a project and do have some driver laying around.
The sidewalls on that are flared, not a lot, but definitely flared. There's less than an inch on either side of the driver in the throat, and the cab is clearly wider than that.
Those would be cool on top of some 15" cabinets that you might have laying around 😉, crossed at ~200Hz.
In my experiments with similar conical shaped baffle/horn-waveguides, I found that even a small amount of curve on the upper and lower panels really reduces coloration. FWIW.
A vintage fostex/foster ribbon tweeter might be nice for top octave on that too.
Those would be cool on top of some 15" cabinets that you might have laying around 😉, crossed at ~200Hz.
In my experiments with similar conical shaped baffle/horn-waveguides, I found that even a small amount of curve on the upper and lower panels really reduces coloration. FWIW.
A vintage fostex/foster ribbon tweeter might be nice for top octave on that too.
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