Kofi Annan in: "225K: The Lonely Fostex"

[Kofi Annan]

So, I got to looking at some Fostex drivers this morning, much to Mrs. Annan's dismay, and I came across the 225K. The response in the higher end seems much smoother than my 206Es and, while I realize this would need a tweeter, it looks like a fine driver, based solely on the SPL response.

Now, Kofi don't know nuthin' 'bout boxin' no drivers, so I looked for a recommended enclosure for these and it appears that Fostex only has a bass reflex design they recommend. I was hoping for a back-loaded horn. Well, actually, I was hoping for a quick resolution to the Syria - Lebanon thing, but a horn'll work too.

Also, my searchifying turned up ungatz on any other recommeded encosures for these, hence the need for another Kofi Original Post(tm).

So my questions are as follows:

1. What's wrong with this driver? Why aren't people talking about it on the fora (forums pl.; cool, right?)? Is it just because of the required tweeter or are there other Thiele / Small issues that make this undesirable?

2. If this is an OK driver for an SET setup, could I use it in a horn or not?

3. Anyone have experience with this driver and the 206E that could let me know what they liked / disliked in comparison?

4. Anyone with experience in Syrian - Lebanse relations that needs a job with lots of international travel?

Help a brother, will ya?

Kofi

[HWV]

Hi Kofi,

I've wondered about the 225K as well and like you, searching the 'net and fora hasn't turned up much. But! I may have some information that may interest you, and some that is completely useless.

Question:
1) What's wrong with this driver? There aren't any 'proven' designs on the net. This tends to eliminate it from general use. It's hard to go out on a limb and spend a couple hundred bucks (for me) on drivers that might not be what I am after.

2) If this is an OK driver for an SET setup, could I use it in a horn or not?
Probably; Maybe. Again, without anyone having any experience with it, it's hard to know for sure. It does look suitable for a back horn, or even a midrange front horn. That would be cool!

3) Unfortunately, I don't have any hands-on experience with the ff225. I have built a set of the BLH for the 206e, so, no help there.

4) Anyone with experience in Syrian - Lebanse relations that needs a job with lots of international travel? 'Fraid not. Although I could use a bit of travel!

So, now for the (possibly) useful stuff. I snagged the set of books that Madisound offers, "Nagaoka Tetsuo's Special Technique to Design the Original Speakers" (catchy title, hey?) when they first came out. In the books, there are about three bajillion different enclosure designs, mostly for Fostex drivers. When I say your post, I thought, "Gee, there has to be at least ONE BLH for the ff225k in there!".
Alas, there wasn't.

BUT! There were a handfull of other designs that used the driver. So, check them out:

Sorry, the pictures in these links are a bit too detailed to be considered "fair use", so we've put them to bed until permission from the publisher can be obtained... dhaen

I know that I am breaking copyright, &c, yadda yadda, by posting these. If you like them, get the books. If only for the design that looks like a huge robot!


-Hans

[fergs1]

just curious kofi are you unhappy with the 206 or is it simply pe (parameter envy) my 206 are in a pair of Rons Dallas II blh and when I first had them in the topss were really annoying and I got panicky.I had a heap of mods lined up too tackle this.thankfully
1) I was slow in the uptake and
2) I listen to a lot of music which had the twofoldd benefit of massaging my lugs and also properly breaking in the driverrs at the same time.now they are very good.
whats my point? firstly are your 206 properly broken in and are the in a properly designed cabinet ie blh
by the way I always enjoy your posts cheers fergs

[sumacSK]

Hi,

Try to look here:

http://gallery.audioasylum.com/cgi/v...21168&session=

http://db.audioasylum.com/cgi/m.mpl?...5k&r=&session=

http://boozhoundlabs.com/ff225k/

I think that the biggest problem with this driver is that it has xmax of 0.3mm so you can't expect much bass comming out of it.

Good luck Martin

[carlosfm]

Originally posted by HWV
http://furtive.us/images/speaker/E-7...25k%20plan.jpg

Assuming that the FF225N is the same as the FF225K, it doesn't make much sense to use a 2.2uf cap on the tweeter, does it?
9K?

[HWV]

Assuming that the FF225N is the same as the FF225K, it doesn't make much sense to use a 2.2uf cap on the tweeter, does it?

Looking at the PDF, 9k is just under where the driver response drops off the chart. Not a completely bad place to hand-off to a tweeter! It is a good place to start, anyway.

I'm sure the details would be much clearer (for me anyway) if I could read Japanese. Ahh, back to school I go!

-Hans

[carlosfm]

Originally posted by HWV
Looking at the PDF, 9k is just under where the driver response drops off the chart.

I'd say it's around 12k.

[Kofi Annan]

It's hard to go out on a limb and spend a couple hundred bucks (for me) on drivers that might not be what I am after.

That's why we're asking the questions. I see you're in my camp.

So, now for the (possibly) useful stuff. I snagged the set of books that Madisound offers, "Nagaoka Tetsuo's Special Technique to Design the Original Speakers" (catchy title, hey?) when they first came out. In the books, there are about three bajillion different enclosure designs, mostly for Fostex drivers. When I say your post, I thought, "Gee, there has to be at least ONE BLH for the ff225k in there!".
Alas, there wasn't.

BUT! There were a handfull of other designs that used the driver. So, check them out:

Wow! Thanks so much for scanning these! I love the concepts here, but I'm still wary that there may not be enough feedback for me to venture forth and buy 'em. Apologize if I sound like I've had a few, but I have a cold and I went to my local Irish pub and had a few hot whiskeys and a few cold ones and, well, you know the rest...

I love fat girls. I really do.

That's the booze talkin'.

I think that the biggest problem with this driver is that it has xmax of 0.3mm so you can't expect much bass comming out of it.

That's no good. And its been brought up before. The popular myth here is that these drivers have an xmax that actually exceeds the .3mm Fostex discloses, but its certainly an issue, since I want some bass.

just curious kofi are you unhappy with the 206 or is it simply pe (parameter envy)

I am not unhappy with the 206 at all. I like it quite a bit, but I would like to get rid of some of the peakiness in the mids if possible. Also, I have almost no experience with BLHs other than the ones I built for the 206E (I actually built the horn enclosures for the 208EZ to accommodate the 206E at the recommendation of BrianGT). I have, however, performed some modifications to these myself, including M J King's BSC circuit and installing Dave's (Planet 10's) phase plugs.

I must say that the phase plugs have really released the highs and now the 206Es sound better without the BSC circuit than with it. However, I would like to have some speakers that are a bit flatter / smoother overall. Again, I'm not dissatisfied with the 206Es, I'd be glad to recommend them to anyone, but I am looking for an 8" driver that can come close to doing it all, and these initially looked like they fit the bill.

are your 206 properly broken in and are the in a properly designed cabinet ie blh

I have thousands of hours on these and I really like them a lot. Again, using the 208EZ BLH design for these and I would wholeheartedly recommend them to anyone. Except Jacques Chirac. He's more of a bass reflex guy.

So, if I wanted a set of full range 8" speakers (or 6"?) that would provide a reasonably smooth response, could do the bass, had >94dB SPL, could propose Iraqi constitutional amendments, and would work in a BLH for a reasonable price, where would I be? The Afterlife, maybe? Do I already have these in the 206Es, maybe, and I'm just getting greedy? Hey, if it needs a tweeter, I'm down.

Down with the tweeter.

Word.

Hey man, what do I know? Nothing. That's what I know.

A little advice for your reasonably drunk and ill UN Secretary General, here, please?!? Hey, I can actually give you some advice: Did you know that Bushmills is smoother than Jameson? Well, it is. Had a few of each, so I speak from very recent experience. Wanna know which one pukes up better? I may have a hard time discerning, but I'll do my best for the DIYAudio community.

Youguyzarethebest. Iloveyouman. Woohooooparteeeewooo!!!!

Kofi

[Kofi Annan]

Originally posted by fergs1
I had a heap of mods lined up too tackle this.thankfully

Fergs,

Forgot to ask-- what modifications did you make? I have installed Dave's phase plugs and I would consider some cone treatment, but I'd like to know what you did to yours.

Kofi

[fergs1]

greetings kofi, in a word nought unless you count the 6 X 1 in disk of styrene foam glued onto the back magnet as per rons suggestion . this actually tamed some of the midrange forwardness and with the highs settled and house trained the only thing I'm considering is the phase plgs(hands don't fail me noww!) mainly to increase the sweet spot widen the soundstage. I listen to mainly classical and jazz on vinyl but if I was lostening to pop rock all day esp on cd I think i would find the 206 fatiguing.what do you liisten to?btw there's a pic of my 206 with thee foam disk on it in the fullrange driver site. you access thee gallery thru the forum and bring up last uploads, thheres a few Dallas II 's there, mines the one with the fairy lghts. I'd exhaust all other poss b4 putting damar on the cones. takke care fergs