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Fostex BK-16 Horn project

BK-16 at the fest

I concur wholeheartedly. I too was very impressed with the performance of the BK-16 at the fest. My girlfriend was too--so much so that she is looking forward to my tackling the project. :D

I kept going back and forth from the other rooms to the Madisound room, "comparing" the sound of the other speakers I liked with the BK-16. I have to say that they compared favorably with some much higher priced speakers. Sure, they aren't veneered in curly maple, but they also aren't 9 grand or more.
 
One can buy a LOT of curly maple for $9000 :lmao:

Just kidding, but you know I think those are a fine set of speakers regardless of price.
 
I also thought those Fostex kits were excellent!! One question, why did they have to make them with chrome dustcaps? (shoulda been the same colour as the cone, IMO)
 
Celt said:
You can order the BK-16 cabs by themselves. The front and rear baffle boards are doubled for extra thickness and the horn folds provide the crossbracing on the outer walls (rear included). Anyway, if you order a pair of cabs, a pair of FF165K drivers and a pair of the gold-plated binding post cups, it comes to just $325. A true bargain.
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Hey Celt

Would you happen to have a link where I can buy these kits?
Certainly have my interest!:banana:

Send me a PM.

Thanks :D
 
Everybody else has already said it well but those kits just seem to be truly outstanding especially for the price. I can't think of anything even near them in cost that would match the sound that those speakers were putting out. The cabs are practically being given away.

And for other maniacs...one of the madisound guys told me that they are looking at putting together a larger full range kit with 8" drivers and a flat pack. I think he said they were talking about calling them BK-20s. They'll have to be a lot more expensive though than these guys...bigger goes up in price quickly.
 
Seriously considering building a pair!! :banana: :thmbsp:

I'm curious though.....If you buy the whole kit it is $635 but if you buy pieces and parts it is $325....Are those $300 tweeters??
 
PioneerGuy75 said:
Seriously considering building a pair!! :banana: :thmbsp:

I'm curious though.....If you buy the whole kit it is $635 but if you buy pieces and parts it is $325....Are those $300 tweeters??
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Yep. Did you pick one up? Heavy!!
 
PioneerGuy75 said:
If you buy the whole kit it is $635 but if you buy pieces and parts it is $325....Are those $300 tweeters??
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Actually, I think they list at $190 each, which has me wondering if there isn't another option between no tweeter and them.

Like was said before, if they pick up at 12,500 hz, a lot of us might be missing a lot of what they contribute. I just wonder if there isn't another, less expensive tweeter we could use in it's stead; the crossover looks to be just a cap in series?
 
Andyman said:
Actually, I think they list at $190 each, which has me wondering if there isn't another option between no tweeter and them.

Like was said before, if they pick up at 12,500 hz, a lot of us might be missing a lot of what they contribute. I just wonder if there isn't another, less expensive tweeter we could use in it's stead; the crossover looks to be just a cap in series?
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If you'll read my posts, you'll see the FF165K driver is essentially flat to 15kHz and and useable to 17kHz. Again, the cabs, drivers, etc. are all available individually and buying the tweeter/crossover networks is NOT mandatory.
 
Andyman said:
Actually, I think they list at $190 each, which has me wondering if there isn't another option between no tweeter and them.

Like was said before, if they pick up at 12,500 hz, a lot of us might be missing a lot of what they contribute. I just wonder if there isn't another, less expensive tweeter we could use in it's stead; the crossover looks to be just a cap in series?
Click to expand...

Ooh, now there's a thought. Buy the cabs and drivers, add a less-expensive tweet on a top-mount like the originals, and give it a run. Since none of us have the hearing of a 14 year old, it might work just fine, at a lot less money.

Personally, after too much shooting before ear protection came into common use, my highs aren't all that good, but I could definitely tell a difference with/without the tweeters plugged in, so I probably wouldn't go tweeterless.
 
I liked mine better without the tweeters. Matter of fact doucanoe is using them with his Frazier/Altec/Fostex combo and they sound sweet in that system.

I never really liked the way they integrated with the Fostex, could not put my finger on what I didn't like.

For the price they are a steal. Here is another example of a flat kit, but more dollars. They are supposed to be great by the way.

http://www.planet10-hifi.com/FH-flatpak.html
 
I can't imagine wanting to add a tweeter. The off-axis response of the driver is as good as most tweeters, although not as extended. But I like to keep things as simple as possible.
 
I heard an AEG/Audio Research combo at a friend's place. Very nice midrange. Lifelike. Celt, you did a great job on those. Gorgeous. Have any of you tried Altec 755x, JBL D208/216 or LE8's?
 
gonzomeep said:
I heard an AEG/Audio Research combo at a friend's place. Very nice midrange. Lifelike. Celt, you did a great job on those. Gorgeous. Have any of you tried Altec 755x, JBL D208/216 or LE8's?
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Been playing around with full range drivers most of my life. Had some nice results with alnico eight inch Oaktron, Utah and Philips drivers. Also had a pair of Western Electric's that a local AM station threw out. But that was thirty-five years ago. Wish I still had 'em!
 
Oaktron's!! You brought back an old memory!! I owned a beautiful pair of Oaktron's many moons ago. They were 8" fullranges with an aluminum dustcap and a whizzer cone. I believe they were Alnico. The baskets were a nice blue color. I wish I still had them. I haven't seen another pair in 20 years.
 
Well, after a period of extended listening and allowing for any possible break-in, I decided that there was tilt on the top end that was working my nerves. I measured and what I heard and saw on the cut sheet, confirmed a hump centered @ 8.5kHz and a smaller bump @ 3.5kHz. I knew this wasn't something I could live with long-term. It was either find other suitable low-q drivers or try to modify what I had. I was certain the aluminum dustcap was the culprit, but assumed that Fostex had dampened them from behind. I decided to sacrifice one driver to see what could be done.

The dustcaps are attached by a heavy bead of black epoxy. Using a fresh X-Acto knife, I split the aluminum cap across into four sections and then very carefully went in at an angle against the epoxy bead and slowly removed each quarter. These caps are extremely thin and had no internal dampening. I could see why I was hearing what I perceived to be a slight ringing and tizziness.

I then carefully vacummed out any possible contamination from the gap and then re-measured the response of the drivers. I was happy to see that the 8.5kHz hump was now gone and that the smaller 3.5k bump had moved down and diminished slightly. Frequency extension still remained at reference to 12k and down slightly @ 15k Hz.

I then carefully took the four pieces and using a digital scale, weighed them to be slightly under .50 grams. The stock caps are just a hair over 1.75" in diameter. Luckily, I found replacements made of paper fiber from Speaker Works Northwest in Eugene, OR (1 7/8 Inch Dust Caps - A) for $7 a pair and they came with gap cleaning tape, cement and a brush. They fit perfectly to the outer edge of the epoxy beads and using the supplied cement, were very easily to install. After letting them cure out overnight, I remeasured the drivers and was happy to see that the hump was still gone and that the frequency extension didn't suffer either. Still ref @ 12k, strong @ 15k and usable @ 17k Hz.

Below are three pictures of what they look like stock, with the dustcap removed and then with the replacement paper dustcap.
 

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