Fostex (2) FE208 with (1) T90 Tweeter

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On the Madisound website, while looking at the Fostex T90 tweeter, I noticed a schematic showing how to connect (2) FE208 fullrange drivers to a T90 tweeter.

https://www.madisoundspeakerstore.com/bullet-tweeters/fostex-t90a-top-mount-horn-super-tweeter/

My question is, has anyone seen such a completed speaker? I would think it may make an excellent match to my SET amps. I am a pretty good woodworker but I lack the smarts to figure out how to design an enclosure for that combination of drivers. Could anyone shed some light? Thanks.
 
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Those FE208 drivers really need a back loaded horn to work well. They are very low Qts and have a tiny xmax. I haven't seen a BLH enclosure for a dual FE208 sigma. I don't think you need a dual driver for a good BLH. In any case, Fostex has a recommend BLH cabinet but not sure how good those are. The BLH experts will chime in but there is probably an existing computer model optimized design.
 
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I ran the FE208 in RCA Fan's rear loaded horn (with Karlson winged exit) for a couple of years. Damn good sound. Lots of kick, dimensional sounding, albeit with an odd resonance or two around 80 to 200Hz range, but only excited by some tracks. The only caveat is that, even though, it may be sensitive, the fe208 really shines with a lot of power. Don't recommend the T90a as it is a bit harsh; mine have been in the boxes for the last 10 years or so.

I would guess that two would be awesome, but might lead to some tinkering with the second FE208. Actually, the FE208 sounds good all by itself, but of course that is the "unpopular" use as the specs show it rolling off too early. Perhaps, an inductor to roll it down around 1kHz or lower, maybe even a mechanical lowpass if you are into trial and error. AFA the tweeter, I would even go as far as to say that a cheap piezo (loaded into a horn) would sound as good or better than the T90a. Just make sure it is properly incorporated.
 
Typical Fostex over priced offerings. A $45 unit from PRV has better specs.
PRV Audio TW600Ti High Power Titanium Bullet Super Tweeter 8 Ohm

But wait, I need to get the Fostex because I will miss all that stuff between 22kHz and 35kHz :)

It might be good, but I wouldn't assume anything without distortion measurements, CSD, etc. I've been burned a couple times with small horn tweeters. They can be truly awful.

Compared to Goto and other exotics, the Fostex supertweeters are dirt cheap. :D The T90A has gotten very expensive because it is alnico, the price of which which is related to the current price of cobalt and global politics. There's also the FT96, which is somewhat less expensive.

AFA cheap supertweeters the old CTS piezos could sound great, with a couple mods. Distortion is very low, but freq response isn't supersmooth, which in practice isn't as important in a supertweeter IME.
The old Realistic (foster) 40-1310 was quite a bargain, and often were on sale at $30, but they are long extinct.

Good luck with ribbons as supertweets. I have yet to hear one that sounds good in a high efficiency super tweeter setup to my ears, and I've heard a few. Ribbons are fantastic in the top octave, but they are tough to integrate, and often have high distortion in the lower treble. That said I like ribbons, just not for this.
 
>>> AFA the tweeter, I would even go as far as to say that a cheap piezo (loaded into a horn) would sound as good or better than the T90a. Just make sure it is properly incorporated.

As much as I like piezo's I don't think they will sound as good as the Fostex. I am familiar with the $37 Fostex vs piezo's and they sound totally different. The Fostex has a sweeter sound, the piezo dryer and splashier.

I've never heard a dome tweeter I enjoyed and I've had expensive Dynaudio's, Vifa's and some others. Fuzzy and vague sounding to me.

My favorite tweeter is

Eminence ASD1001 1" HF Titanium Horn Driver 1-3/8"-18 TPI

Mounted in this

Dayton Audio H45E 4.5" x 4.5" Elliptical Waveguide 1" Threaded

The newer model measures even better

Eminence ASD1001B 1" HF Titanium Horn Driver 2-Bolt 8 Ohm

Honestly, this is the only pro tweeter I've heard but it recreates the impact and scale of real cymbals better than the other tweeters mentioned above.

I'm sure others will disagree (and that's fine) and I hope not to derail the original poster's thread.

http://www.pranawire.com/images/ben1-5.jpeg

Midwest Audiofest - Hi-Fi Show Report on TNT-Audio [English]
Scroll down...

Not exactly what you're looking for but close and may help determine how these drivers could be used... if you've got the cash to purchase them.
 
Yo Godzilla, RE piezo sound: Try taking the piezo apart, spraying or brushing some dammar onto the paper diaphragm, and wrap some clay or sound-deadening goop around the horn and the chamber. Put a little felt in there too. Bridge a decent 8R power resistor across the terminals, and perhaps a 1uF highpass cap. Then try them... Also nice if you remove the horn entirely. Works for PHY... ;)

Good to hear the ASD1001 sounds good. I really liked the old Eminence APT50, but reports are the new version is a major downgrade.

One more thing, and I apologize in advance to anyone I insult, but this bears repeating because it is often a problem: Remember to USE AN L-PAD when you connect your 106db horn tweeter to your 90db full range!
 
Thank you gents. I have not heard the Fostex tweeters, but I have heard the PRV D290PY polyimide compression driver and is sounds very nice! Very crisp and articulate in a non-fatiguing way. PRV Audio D290Py-B 1" Polyimide Horn Compression Driver 8 Ohm 2/3-Bolt I have it matched to a 10" JBL woofer in an 'econowave' type setup. I use these speakers as a PA speakers but I need something 'high end' for the house. If I could find another pair of 10" JBL 127H4's, I'd build a pair of high-end looking (high wife acceptance) speakers for the house.

Perhaps I can tackle my problem another way, I want a very efficient speaker that plays down to at least 60hz and has drivers no larger than 10", preferably 8". Any ideas? When I saw the specs for the Fostex, I thought my search was over. Perhaps there is a way to marry a pari of the Fostex 8" to a B&C DE250 which I heard sounds even better than the PRV polyimide driver?
 
Dudes! don't knock supertweeters until you've tried it. They can do wonders for imaging. It may seem silly to have that kind of bandwidth, but having a driver in the heart of its BW 10-20k instead of in breakup mode is IMO better...

That said, this is really a topic for another thread. :D

Godzilla, I remember your old project of course. Forgot that you did the full tweeks. It does help to damp the cup too, and don't be shy with the dammar. IMO it comes pretty close to a real supertweeter when fully tweaked, especially for $10 (once upon a time)


That dual FE208 contraption looks like it was designed by Mr. Goldberg as a patented diffraction generating device. :devily::redhot:
 
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