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Old 4th August 2006, 03:15 PM   #11
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Dunno about the worksheet guru bit, though I'm a massive supporter of Martin King and his work. I do my best anyway.

Yep, dimensions are all correct, and your proposed construction method and materials spot on. The only alternative I can think of would be to laminate 1/2in particle board to 3/4in birch ply, though that's a lot more involved of course. Big enclosure this one.

One point that's only just occured to me though is that with the theoretically ideal conical expansion, that huge magnet very probably isn't going to clear the sloping internal baffle. If you want to stick with the 'ideal' expansion, you'll need some form of false baffle, like the one Terry Cain uses, to mount the driver on. Get some nice hardwood about 1 - 1 1/2in thick, and about 6 -7 in wider than the driver, and get the local cabinet maker to shape it on his lathe, if you can't do it yourself.

Alternatively, you could depart from the ideal theoretical expansion slightly and go to dimensions which will allow the magnet to clear the baffle naturally. 9in wide x 15.5in deep should do it. (excluding the build material). Terminate the internal baffle 7.75in from the internal front, base and rear walls.

Stuffing is rather room-dependant. I usually start by stuffing the point above the driver lightly, and putting a 1in layer on the base. After that, I wait until they are in the room, and adjust their position, and the amount of stuffing from there.

I'd hang fair on the tweeter until you've heard the drivers without it. You could try it in a pod, or perhaps rear-firing as TC does with his double BENs and Super Abby respectively.

Hope this is of use
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Old 5th August 2006, 02:45 AM   #12
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Default 206es-r

Actually, I think that the 206esr does have the cobalt lanthanum magnet. it is a ferrite magnet type, just like the 166esr was. the cobalt in the mix makes it a special ferrite magnet. there are many ways of mixing the magnet metals as alloys.

look around on the japanese sites. they cite lanthanum cobalt. though admittably, there seems to be confusion about this all over the web (what's new?).

Ill put it this way, the 206esr sounds "lanthanum cobalt" to me. just like alnico has its own sound and straight up ferrite has its own sound.

anyways, I will be building the recommended enclosure out of void free baltic birch, 18mm soon. I tried to find luaun core material, to no avail. oh well. birch sounds great and is of good specific gravity.

I bought the t90aex, the p208 brass ring, I got the brass tweeter stand, fostex cs .47 cap. and a nice attenuator.

adding up to nearly 2000 bucks in parts, these things will be a huge expenditure in parts, time, etc, especially for a lowly college student like me.

about the BIB - when i built the 166es-r BIB, I like it for everything as a balanced whole. there is little problem with lower frequency resonances in this enclosure.

it does have front baffle resonance issues. they are not distracting, but they do muddy the sound a bit. I consider it to simply be a tradeoff of this enclosure in general. use the right wood for the driver, and it might help... in the end, it is a very acceptable compromise, I feel. however, the lightining speed of the 166 I know is there is a smidgen not as obvious as I would desire. i am a bit more of a detail freak than some, but not others. most people hear this speaker and conclude it to be the most detailed they have ever heard. and in many respects, it is the most detailed i have heard. it kinda does everything well. it needs the right room though. reflectivity is highly desirable. we do not want to shake the floors, instead the ear drums. it relies a little too heavily on the room making the bass for my tastes, actually. course, I do not have the right room for them. in older, plaster ceiling, plaster wall, wooden floor homes, they do disco bass. in my apartment, with crappy acoustic ceiling tiles, low pile carpet and less than solid construction, I have to eq it back in...

so before one builds the 206esr bib enclosure we must consider this perhaps?

most of the orthodox (long path) front mouth opening blh end up being installed in a room. they need a certain amount of damping to fit into their acoustic environment. this is frequently to take a 150hz or so bump in response, but that can vary, depending on construction material, amps, room, state of mind, etc. this takes a while to determine. it is nearly impossible for the layman to determine reliably, let alone control. it is still hard for me to determine.

reviewing some lessons - square during construction is vital. break in is vital. proper damping inside and outside the horn is vital. placement is important. amps are important. cables are important. that is all I can think of here.

when tuning back horns, I arrive at an idea of nothingness eventually. to make the speaker sound like nothing (at least as much as it can). this is showing of a lack of ego of the speaker builder (as opposed to "listen to THAT frequency region!"), a settled nature of components, and a peaceful mind. my only goal is balance. compromise. sometimes, in this country, with that goal, I feel very alone.

in thinking of the large orthodox front mouth blh it is hard to think of them as having alot of economy, simplicity, smallness, or an ease of distribution.

in their problem (lower vocal resonance), they gain super powerful and disappearing bass. with a horn, there are various amounts of LOADING. loading with room, loading with the horn, acoustic impedance, etc. it does not stop and all values are floating. ahh! the goal is to tune the resonance out to the point that it does not distract, while maintaining enough bass. given that many rooms resonate in the 180hz and below region, this can add to the complexity of the situation. it is the same with the super tweeter.

In single driver speakers, the horns we place on top and bottom I like to relate to salt in a food dish - it is a flavor enhancer, and should not be tasted as salt itself. course, everyone has their own tastes here. some people really want to HEAR that 500 dollar super tweeter... hence the complex nature of any of us here giving any "solutions" to each other. only relating experiences and learning from our own and those of others.

hence the complex nature of creating especially these more state of the art horns as product... how many reviewers are going to remove the driver and tweak with damping for half a week? when their conclusions are kinda subjective annyways? how many customers are going to open their horns and peer into their souls? and their own souls to find the answers only to find out that there are none.

there are ways around this that I will not go into here. everyone has their own way of slicing the pie.

I am choosing to build the long path horn of orthodox nature as I consider it to be the best match for this driver.

also, there is the problem with BIB as having a huge front baffle that resonates in the upper regions and muddies sound there somewhat, especially with these higher speed drivers, mass loading via brass, double thick ply, or both is important.

if detail is not the final goal, concentratiing on getting good tone out of the cheaper drivers is ultimately a more worthwhile pursuit.

it is all tradeoffs. for most people, and most DIYers, I think that BIB is really the best solution. we read up on that current forum. the ones I want to try is a large mouth 168EZ, and the larger 103e.

I dunno, I am full of opinions. probably full of crap too. I hope y'all can learn from this and also refute me and teach me a bit.

one site I found particularly helpful with this driver is the spi sound plaza. the japanese version has some updates on the 206es-r driver and the t90a ex. get google to translate it for you, drink a few beers, invite some audio freinds over, and have fun reading it!

well, from out here walla walla,

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Old 5th August 2006, 03:08 PM   #13
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I stand corrected re the magnet.

Perhaps something like 3/4in classic core with it's 2, 1/8in MDF internal substrates and ply external layers would be the best solution for building, if you can get hold of it. Mind you, I don't exactly think you and TC need any suggestions from me about build materials! Doubling the front and rear panels on the BIB works well -my 165's cabinet has just this; a 3/4in layer of MDF laminated to an internal 1/2in layer of chipboard. Also gives the driver a bit more breathing room if it's tight to the sloping baffle, providing you over-size the cut-out on the inner layer or bevel it. A false baffle could also help kill some of that panel resonance.

You're right about the BIB being room-dependant -ye olde style construction is best; a ceiling with acoustic tiles doth not a happy combination make, as you so rightly say.

I do like the BIB as a design though over most 'normal' long-path length horns. Long most of them may be -but not long enough though. Unlike most, the BIB gets to 1/2 wave. Of course, you then have to compromise mouth size with Vb to get the load right, so as Greg is fond of saying, no free meals here! They do get a heck of a lot of gain though in the LF, being so long.

I remember Terry suggesting in a discussion re the FE166ES-R a while back that it's possible to double the factory horn -keep the CC the same volume or fractionally larger, and possibly reduce the total throat CSA somewhat, so you could probably do the same with the Factory FE206ES-R horn. Of course, the flare rate will be changed due to the doubling of the mouth CSA. How that'd work out I don't know -horns are not my field. It's certainly not the normal way to go about designing a double horn, but if TC says it's possible, then it must be. Draw your own conclusions on that one!
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Old 6th August 2006, 12:20 AM   #14
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Default yup

yeah, I love the BIB as a concept, an actualization, and as an artistic entity.

seriously, the bib just sounds good, in that oh my god what is happening sort of way.

yeah, a double horn for the esr would be pretty killer. as a shameless plug, cain and cain does do custom double horns, big and small. I happen to have a pair actually....

the esr would shoe horn ( heyuk heyuk) into the large double horn easily. monster bass would result.

damnit if i havn't seen god through the 8 inch sigma drivers in those cabinets. course, they are expensive and ungodly large.


double horn would need the smaller throat area, smaller cc, etc. fewer folds. it would sound nice. a hard beast to tame though.

well, see y'all in a bit. any advice as to how to upload photos?


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Old 6th August 2006, 09:18 AM   #15
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Simplest way, providing they're not too big, is to go to browse on the reply screen and navigate to whereever it happens to be on you HD. Then click open. When you post your reply, it should be attached. There's ways and means of ataching several to one post, but how, I'm not sure though, never having needed to do it myself.

You have some double horns of the C&C variety. Why does this not surprise me? I am currently a strange shade of green. Envy. Pure envy. Custom ones as well -I should really have guessed, though I didn't know for certain that was the case.

The sim I did on the first page was for a 206ES-R double horn, of the large CC, short path-length type (think double Replikon). Just a different approach really. I quite like them. I'm currently fooling around with one for the FE126E as well, which I might actually have to build -the sims look pretty good so far.

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Old 7th August 2006, 03:37 PM   #16
fred76 is offline fred76  Philippines
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Actually, I think that the 206esr does have the cobalt lanthanum magnet. it is a ferrite magnet type, just like the 166esr was.
FWIW, eifl export still has a pair of the limited edition FE208ES for $400. This is one extends up to 20kHz and is more efficient than the standard 208EZ. Dual magnets may neccesitate a 'false baffle' fora BIB. The T/S was published before in Fostex Japan's website, but I guess Koji still has the accompanying documents for these.

Click the image to open in full size.
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Old 7th August 2006, 07:03 PM   #17
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Slobber. Want some, want some!

I'm now off. To rob a bank.
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Old 4th December 2006, 03:44 PM   #18
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Default Brass rings with Fostex FE-206 ESR ?

A quick couple of questions regarding the brass rings that fostex sells for the FE208E sigma and that fit the FE-206 ESR :

1) I will be building the box next week (see previous post on the design) and the clearance between the back of the speaker's magnet and the inclined panel is extremely small. Does it make sense to invest in the brass rings that Fostex sells to get more clearance or does it creates some anomalies (see blumenco's post)

2) For the cap and coupling with the T90 AEX, shall I go with a .33 mfd or .47 mfd ?

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Old 5th December 2006, 09:39 PM   #19
no xo is offline no xo  United States
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Sierra, I have played with both a .47 and .33mfd cap and to me the .33 cap blends the T90AEX with the FE206ESR the best. I built the Fostex recommended horn for the FE206ESR and did not like it at first. It took much break in and alot of good advice regarding stuffing and damping before I started to enjoy them. Bluemenco and Kloss` posts were of great value to me. Add stuffing, listen then remove some and listen more. Add some back, then listen more and continue the process until YOU like the sound in YOUR room. I am a newbie, or what I would call a greenhorn (a horn builder who lacks knowledge and expirience), but this was a very satisfying process and I learned alot. Now I`m beginning to learn the ins and outs of tube rolling and the effect they have on these horns. Build some horns and you`ll have something to play with for years. This is a great hobby.
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Old 6th December 2006, 12:24 PM   #20
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Thanks No Xo.

I am currently planning to build the BIB / TQWT enclosure and not the recommended fostex enclosure for the FE 206 ESR. Simpler for me to do as I have no access to a good workshop.

I will try the .33 cap as per your recommendation and take it from there.

I was also planning to fix the loudspeaker on the enclosure using a wooden ring (similar to Cain & Cain system) but since I can get the fostex brass rings at a reasonable price, I was wondering if anyone had experimented with them.
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