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Back Loaded Horn with FOSTEX, some questions... - Click HERE for Original Thread

Guijs

Hello,

This is my first post on this forum :wave2: . I'm planning on building a BLHorn to use with Fostex speakers, but i'm not shure wich driver to use. I have in mind the FE168ez Sigma, FE208E Sigma (old one) and FE208ez Sigma (the new) and I have some questions:

1) The old FE208e goes up to 20khz, the new one goes up to 14khz and needs a tweeter (Fostex recomend the http://www.madisound.com/pdf/fostexdrivers/t90arev.pdf U$141 each). The old one is really better than the new one, or I'll need a tweeter anyway?

2) My room have only 14m^2, would the FE168ez be a better choice over the 8'' Sigma's, giving sufficient bass? Plus it goes up 21khz!

3) Fostex recommend the T90A tweeter, wich is expensive (U$141). The Fountek NeoCD Ribbon tweeter costs U$83 could be a better choice? There is another not so expensive driver?

4) I'll make a BLHorn. The Fostex recommended plan are the better ones?

Sorry for all the questions.

Thanks

Scottmoose

I'd go with the FE168Esigma and the Fostex design. It doesn't need a tweeter, so instant saving there, and it doesn't need such a large room as the larger drivers, so will probably better match what you have than they would. I like the Fostex cabinets (I'm going to be building a doubled FE103E cabinet very soon -I've already built a pair to the original single-horn design and loved them), but there are other options available too, though they won't be as easy to build. Swan! Who said that?!

Cheers
Scott.

robertG

I had three pairs of FE168EZ (all Fostex cabs), two FE108EZ (Fostex cabs) but no FE208EZ.

If money is no object, go with the new FE208EZ. Main reason is that the FE168EZ is sometimes annoying (beaming issue). Having a seperate tweeter gives you a whole lot more control over the sound (you can use the 208 FR or roll it off a little, then add a ST to taste).

Not so with the FE168EZ, you live with what you got, unless you roll the highs and add a ST (or experiment with resistors). So it's kind of a no-brainer.

Also, both Fostex specs for FE168EZ and FE208EZ are almost the same size (BIG!).

Question, do you like bass? Do you plan to use a sub? if so, may I suggest you try a FE108EZ? This may seems like an odd proposition, but the highs in the FE108EZ are much more smooth and better dispersed than the FE168EZ, the bass extension is almost the same (but it's a non issue with a sub), except that it won't play as loud. But if you are not looking for ear splitting levels, overall, I think it's a better choice.

Ribbon ST are a real good match for the FE208EZ (none needed for FE168EZ and FE108EZ).

Guijs

Thanks for post Scott.

The FE168ez, alone, give good quality on the highs? Tonal quality on drums plates for example?

Guijs

Robert,

I hear on normal (moderate?) listening levels. I'm not going to use subwoofers, but I want acurrate bass. The FE208ez doesn't need any crossover right, just the tweeter with a 0,68-1,0uF capacitor? How low can the FE208ez go?

I like Jazz, Blues, and rock. But not opera and orchestra. I'll use a DIY Tube amplifier with 5 to 15wrms.

robertG

All three Sigmas will reproduce correctly double-bass fundamental notes with lifelike quality.

I'd say the main quality of these IS the bass and mid-bass reproduction (and of course the midrange). Air is very efficiently moved by BLH, and double-bass, kick drum, grand piano and all percussive instruments sound marvelous.

BUT, some people want low bass (like 20-40Hz), and these won't provide AT ALL. The horn will unload the driver at these frequencies and since they have very little excursion capability they will bottom out if you force them to play very low.

Fortunately, there is NO bass content in acoustic music below 40Hz, so you should be happy with any of the Sigma drivers (in BLH).

By the way, they take a very long time to break-in, so you need to be very patient.

Guijs

So do you think that the FE208ez + Fountek ribbon tweeter will be the best way to go? I found the old FE208 Sigma for less than the new one. Is this better?

Thanks for all the Help!

robertG

Frankly, I didn't listen to any of them (old and new one). I'd go with the new one for two reasons:
1. No wheezer on the new one;
2. Better directivity and tone control (because of the added tweeter, and the abscence of wheezer).

Guijs

FE208ez + Fountek combination seems like the best way to go! But, I have a weird question :xeye: .... Can I put the BLH upside down? Because the speaker will be in a big bookshelf, and it needs to be upside down for the driver to be in my hears level...

robertG

Sure. But the bookshelf will need to be very very sturdy to hold approx. 50 kg...

Guijs

About those L-pads that Fostex recommends http://www.madisound.com/pdf/fostexdrivers/att.pdf , they have great quality for this project FE208ez + Fountek? And about that Sound deflectors http://www.madisound.com/cgi-bin/in...5.22984&pid=311 , they really make difference? How can I make a DIY sound deflector like this (if I would really need) ?

Thanks

Scottmoose

You don't need the deflectors really. The internal right angles to the Fostex horn design (for the love of heaven don't round them off!) act as deflectors, so you get plenty of that effect without any additions. No idea about the L pad, but I don't see any reason why it shouldn't be made to work. Oh, and do remember that you'll be sacrificing some bottom-end if you invert the horn and stick it on a shelf: it uses floor-coupling to boost the bass (i.e. room gain); without that, you'll loose out a bit on this front.
Cheers
Scott

Guijs

Yes, i'm afraid of loosing some bottom end Scott... But this is the only place that it's possible to put a loudspeaker in my room. I believe that I'll loose even more, if I put another type os speaker in the Shelf. Do you have any tip, to less this problem of loosing the bottom end in the shelf?

I'll make a drawning, and post here soon.

thanks

xcortes

I have the 103e in the recommended blh and I would recommend it for your sioze room and volume needs. cheaper and doesn't need any tweeter.
less efficient though. what amp will you use?

Guijs

I'll use an DIY Tube amp, but it's not done yet. I have a friend that make a good amplifier.

I can use a subwoofer to supply the bass that i'll lost in the shelf too. The F103 can give the details that I can reach with a Ribbon tweeter?

xcortes

do a serach and you'll find lots of qualifierd opinions on the fe103e. i consider it a great driver

Scottmoose

If you're going to use a sub, then narry a problem. The FE103E or FE108ESigma would be a terrific choice. The smaller drivers tend to have a more capable midrange and high end than the larger ones, and there's no reason why you can't still use a tweeter. You could even go for a better spec tweeter with the money you save. Or spend it on more music instead. I'm currently building a doubled factory Fostex FE103E cabinet at present, a la Terry Cain's Double BEN. Cheap does not automatically mean inferior.
Regarding the original plan with the 208s, how high off the ground will that shelf be? There are ways and means of recovering some, but it depends on the room.
Cheers
Scott

Guijs

Great! I like the idea of saving money, and space :D . Basicly, the shelf is 80cm (31,5 in) from the ground. Is 275cm large and 60cm deep to the wall. The listening position is almost 3 meters (9ft) away and my ears will be around 110cm from the ground. But I do not have space for a 2m tall speaker. The idea is something below 130cm. The shelf is not in corners, there is space in the sides.

Guijs

Well, I want the best performance possible in my room. It's really thought to choose wich speaker to use. But I think it's better start with the "litte" and not expensive ones. So, FE103 and FE167/166 probably will be the better choice.

Scottmoose

You can't use the FE167E in a horn, but the 166 is a popular option. The FE103 / 108ESigma in either the Buschorn or the factory horns are also regular favourites. As your speakers are going to be off the ground though, my top choice would be to think (and fire) laterally, and go for the Fostex factory spiral horn, designed for the old 108Sigma. With a little fettling, it should work fine with the new model, and being a side-firing type, you should still get reasonable[ish] bass. http://www.fostexinternational.com/...sigma_enc.shtml

Scott

DocLorren

Guijs,

Try the Fe103e and you'll be amazed by the detail and clarity of this driver. First go for a simple enclosure, Fostex recommended boxes or the Solo103 by Tony Gee for example are a good start. Make sure you let the driver run in for at least 50 hours before you start to tweak or add notch filters. You will love it and it is affordable as well. Just remember it is not going to play very loud or go very low. Enjoy.

Guijs

Scott,

Considering that i'll use the speakers off the ground, I agree the best will be these 4'' Fostex. A subwoofer based on the response of the BLH (after break-in of course) will be in charge of the low bass. But, why the old FE108 enclosure and not the new one? What will be the difference in my case?

DocLorren,

The FE103 can play as good as the FE108ez? Because I don't have problem in spending a litthe more on the 4'' Sigma driver. If I can really have more detail with the Sigma's, I prefer to go with them. But, if I can have the same response with the FE103... I go fot it! HARD DECISION!!! :smash: :confused:

planet10

quote:

Originally posted by Guijs
The FE103 can play as good as the FE108ez?

No. The FE108es has one of the best midranges i have heard. It is a bit harder to coax bottom end out of it than an FE103 (one of the reasons it really needs a horn -- or be used just as the top of a FAST system -- or used with a current amp)

dave

Guijs

Ok, so the best shot will be in the FE108ez. Sorry, english is not my language and i'm afraid I did not understand well what you said.. You mean that it's harder to have low bass in the FE108ez than the FE103, that's why it needs a horn. Right?

thanks for the help.

Scottmoose

Basically yes, to an extent. The 108ESigma has minimal cone excursion, so like most other drivers of this type, needs a horn to produce the bass it cannot generate itself. Less importantly, but still a factor, is that it isn't quite as efficient as its cheaper (but still good) 103E cousin, so it needs more power for a given enclosure type. Horn-loading helps, because a driver mounted in a horn is the most efficient way you can mount one, except an open baffle. And believe me, your English is excellent by the way.

I suggested the old spiral eclosure because you intend placing these speakers off the ground. Now, that basically rules out rearward-firing horns as experimenting with distance from the wall is impossible. A front-firing horn-mouth like the current Fostex factory FE108ESigma enclosure is fine when placed on the ground, but because it uses floor-coupling to help generate bass, sticking in on a shelf will most likely rob you of this. The old spiral enclosure, on the other hand, is side-firing. While this too used floor-coupling to help generate bass, this layout will also activate a different room-mode, and should help by generatring bass from both the rear and side-walls too. It's also quite unusual to see them, so you'll have something a bit different.
Cheers
Scott

Alexandertol

Hi Guijs,

I finished building the BLH with the FE-108EZ a few months ago. I play with them in a 17 m� room. I think it would be the best decision for you to choose for the 108. In my room the sound is loud enough, with more then enough bass response.
The reason I choose for the 108 was that they have the most linear response. Also the cone is the lightest of them al, so it has a fast response. I really would choose the 108 instead of the 103, because it is not much more money.
I also read a lot of the differend units and I also considered the 168, but different people wrote that also this unit like the 208 really did need a tweeter ( loke at the frequentie response). Also I loked at a few designs with the FE-206(7)E, because I was worried the base response would be to low. After a lot of consideration I decided for the 108, because like you I have a small room and the gole was to have the best quality in bass, mid�s and high�s with a fast response. Because of the small room the speaker won�t have to deliver high sound pressure.
When my speakers arrived and I toke a first look at the cone, I must say I was a little bit worried. The speaker is a very heavy unit and also the outside diameter is 13 cm, so it isn�t a small unit, but the cone instead is very small. Also my friends thought I was nuts building a that large enclosure for such a small unit. But when my project was finished they couldn�t ( like myself) the amound of sound coming out of such a small unit.
I play with a very 3,5 Watt tube amplifier te Aurexx Crystel 1. The bass is very detailed and fast with enough energy. You can�t believe the amount of sound coming out of the horn�s mouth. It really bang�s loud when you stick your head into the mouth! The mid�s are very open and sound very open and realistic. The high�s are very detailed and I hear every little detail in the music. Comparing with other speakers with good tweeters ( I also have Dynaudio speakers with the Esotec tweeters) I don�t miss a thing. The only disadvantedge of not having a tweeter is the very small sweetpot. Meanig you only will have one seat were the music sound good. Outside the sweetspot the high frequenties will drop rapidly.
About placing the speakers upside down, I think the BLH with the 108 also would be the best choiche, because the horn�s mouth is in the middle and ( I think) it less needs the ground coupling then a design with the horns mouth at the bottem.
If jou have any questions about building the enslosure let me know. I have one importend thing about building them, and that is that you really have to use birch ply wood and not mdf ore other material. You will find a lot of articles about it. With mdf the speaker will sound dead. The horn is like an piano ore a gitar, the enclosure will have to ampifie the sound, not absorbe it.

Succes,

Hi-man

Guijs

First, thanks very much for all the help guys! I'm really glad!

I'll go with the FE180ez!

Scott,

I'm going to build both enclosures, and hear what sounds better. What Alexander said makes a lot of sense, because the mouth is in the middle right? Thanks for the english :D

Alexander,

Man, thanks for the pictures you sent and for the topic reply! I think now I know everything I need. You have a 3,5w tube amplifier? I have a friend, that uses a DIY 2,5w tube amplifier, with a BLH project using a old 6,5'' B&W Matrix midbass and a Foster Ribbon tweeter. It's a very new project and I still didn't heard, but people say that is awesome, excelent BASS, image, depht, etc....

About the wood, I was going to use "naval" plywood BTW, because all the pictures I saw, people was using it! And i'm building a TL subwoofer (for my HT) at the moment, using NHT 12'' subwoofer. I'm using 25mm Plywood.

I think that is it. FE108ez is the one. Now i'm gonna start to save money for the amplifier/pre and a CD/SACD player :D .

Thanks

DocLorren

Guijs,

The reason I suggested the Fe103 in something like the Solo103 enclosure is that it is a relatively cheap and almost foolproof way to build your first set of speakers. If you, however, are already comfortable with woodworking and don't mind spending a few more bucks on your drivers then go ahead and build yourself a nice BLH with the 108EZ.
Guess what kind of speakers I am currently using?
Exactly, Buschhorns Mk2 with Fe108EZ without notch and without damping in the mouth. It is a big step up from the Solo103 but costs a llittle more in $$ and the amount of time it takes you to build it.

Ps. I recently experimented a bit with removing damping wool from the compression chamber. Don't do that. The sound gets sharp and the upper mids shout your ears off. Oh well, do experiment a bit and find out yourself with your upcoming project, it is all part of the fun.

Guijs

Sure, the big fun will be trying these different enclosures! I already have some experience with woodworking...

So we have the Fostex recomended enclosure, the Old Fostex enc. , and what is this Buschhornd mkII?

To break-in the speakers before building the enclosure, what type of signal shoul I use? I used 25hz signal with commom speakers, but the Fostex have really low excursion... Pink noise will be best? How many hours?

Thanks

Guijs

This is a drawing of the shelf, with the FE108ez enclosure. It just need to be a 10cm high (the enclosure) to fit with my hears level. I'll be 3 meters far from the enc. .

DocLorren

Never heard of the Buschhorns?
Do a little Googling my friend!
Although some knowledgeable people from this forum may disagree, I would just let the drivers break in with your favorite music at normal listening levels. I cannot think of a 'premium' method to break in this driver and it has certainly never been tested during a randomized controlled double-blind trial...
It is however amazing to hear the driver go from tinny (barely bettering telephone quality) to full color in a few hours. And then it takes another hundred hours for all the superb tiny&shiny details to show up.

Guijs

Got it! I never heard about the Buschhorn, I'm new in the Fullrange world :D . But I'll do a research!

doorman

I recently built a pair of modded Buschorn MK2's, w/ FE108Ez's. Still breaking in but way more bass than you would think, using this enclosure. The mid-range is as good as I've heard, and these things are really fast. They're a very worthwhile project, Go for it!

Guijs

I'm not going to need any crossover pieces for this FE108ez project right? Just the driver, plugged in the amplifier!?

Hum.... I think the Buschorn will not work in my case, because the mouth is in the back, and it will be to much close to the wall. Very close...

planet10

with RS 40-1197 & helper tweeter....

planet10

and much later -- same box, new skin and an FE108ES

Guijs

Very cool Planet10! I'm going to order my FE108ez pair next month.

Alexandertol

Hi,

You won't need any crossover. You can indeed just hook the driver up your amplefier.
About the dampingmaterial. I just used damping material in the mouth according to the original plans. I used 6 cm thick acoustic foam "pritex". I don't know how you call it.
I haven't ( like the design) used any form of damping behind the speaker. I know another owner, who had put some wool behind the driver. He didn't notice any differance at all. I think because the compressionchamber is very small.
Another tip with building the enclosure is replacing the 6 parts with number 29, by 2 parts of 170x60 mm. I asked around what the purpose was of the 6 parts, but nobody had any idee. The only reason I can think of that the part won't fit the saw plan. In the designs with the 168 and 298 it are also 2 parts and not 6. In the beginning I thougt it were loose parts that you can take out to enlarge the compresion chamber, but in the more detailed plans that come with the driver, you can clearly see the parts have to be gluded for the strenged of the construction. When I have some more time I will mail you the plans. I hope your Japanese is good! Don't worry the plans contains 3D pictures and pictures in what order you must constuct the enclosure.

Alexander

Guijs

Hi Alexander,

It's very strange, this 6 "29" pieces... they don't fit in both side walls, there is some space there! Did you cut the pieces with a circular saw? It will take a long time to cut all these pieces with the circular saw... I have a friend that has a laser cut machine on his job, probably I'll cut there! The pieces will be perfect!

Do you think that the enclosure needs a marble or granite piece on the bottom? A saw some enclosures with this...

Thanks for the plans! It will really help.

Guilherme

Scottmoose

The Buschorn was designed for use in corners, so it's relatively used to being close to walls. By the way, there's a MK3 Bushorn lurking around now. Dave has talked me into doubling a pair of these things (all in the name of experimentation of course) with FE103Es, so it's going to be, shall we say, an interesting project!

However, your drawing indicates it's also going to be somewhat enclosed around the sides too. On that basis, I'd go with the current Fostex factory design as it's front loaded. It doesn't look like you have room either for the old spiral type (pity).
Scott

Guijs

Scott,

There is space in the sides. The shelf is not close to the wall on the sides. On the left there is 70cm from the side wall (it's the window, with a curtain) and on the right I have more than a meter, with a opening to the closet.

chrisb

The Buschhorns photos posted by Dave above were formerly in my system, and I got the best sound with them (and all other speakers before and since for that matter) with an apex/diagonal placement
i.e. the plane of the front baffles forming the base of an isosceles triangle, with a room corner as the apex.

While both speakers are at an angle and much further away from the corner than a "standard" corner placement, they are both loading into the same corner and there's some good room gain happening. Also, you only need one decent corner, and in my case while the other corner might be "available" it's over 15 feet away.

In addition, with a bipole (and if you put your ear to the mouth of the Buschhorn, there's quite a lot of energy well into the midrange coming out) you'll get a fair amount of delayed side wall reflections that can contribute to "soundstage"

For an interesting article that graphically represents the placment:

http://www.decware.com/paper14.htm

I'm sure Steve didn't invent this set-up, but it has certainly worked for me for over 5 years.

Alexandertol

Hi Guijs,

I have sent you a mail with a scan, as prommissed, of the original drawing you get with the units. The rest of the plans contains the drawing you will find on the Fostex site and a lot of Japanese:confused:. If you look good in picture number 1 you will see that parts 29 are replaced by 4 parts. Now they fit and there's no place left. It's importend that it fits the side wall for the extra strenght of the compression chamber. I still don't understand the idee of the 6 lose pieces, the only reason I could come up with was that it didn't fit the cutting plan.
A piece of granite would look nice and I think it will work. In the original design you can fill the compartments in the bottem with sand. If your speaker is upside down it isn't possible, it will fall down. With the granite platform you will get the extra weight. I haven't filled the compartments with sand yet. What I last did was put some spikes under it so it stand more stable on the ground ( I have carpet), it was a lot better:D.
One question: It is possible to line the speakers directly to the listening position? What I mean is if the speakers face straight to the front, so that the don't point directly to the listening possition, You will have a lot of loss in the high frequenty. So you will have to be able to turn the speakers to the inside, directly pointing to the listening possition. Then you can experiment with turning them bit by bit to the outside to get some more depht in the soundstage.

Guijs

Chrisb,

Thanks for the explanation, I'll read the articles carefully.

Alexander,

Thanks for the scan, I can't read it but the pictures are nice :D . As you can see on my shelf drawing, there is some space on the enclosure place in the shelf, so I can move it and point directly to the listening position! No problem with that. About the granite, I think it will be the best way since since I can't put the sand bags...

pieterv1

To Guijs (and others):

To avoid doubling of my contribution to questions about implementation of 10 cm horns I give this signal to Guijs.

In the thread 'compression chamber size' I have given today some thoughts to your question about 'placing a horn against or too near to a wall'. Go to that thread for more information.

I also asks in relation to that thoughts for some hornparameters for use of the fostex fe108ez, but that's a question that reflects issues of several other threads on diy also. The answers others will give to that specific parameters can be of interest for your decisions on wich cabinetimplementation will be chosen by you.

Greetings.

Guijs

How many amplifier Watts RMS (from a pure triode tube amp)the FE108ez can handle? What is the recomended power? Is it possible to reach up to 100dB with the FE108ez ? Not saying that i'll hear in this level all the time... but I have my "loud" moments.

robertG

The efficiency is roughly 90dB /1w / 1m
so
93 dB / 2 w
96 dB / 4 w
99 dB / 8 w
102 dB / 16 w

Assuming you do not listen at 1 m distance, but at the same time your room is not that big, you probably could get 100 dB - brief -peaks in the midrange (I very doubt you can push that high in the 60 - 100 Hz region without damage - especially with the Bhorn)

Guijs

I'll be 3,5m from the speaker. So, around 10w will be good. Can you guys point me to some tube amplifier projects with this power?

thanks

Guilherme

chrisb

After several iterations of very basic SET amps, loosely based on a small scale commerical product, I tried both the EL84 and 34 versions of Alex Kitic's designs.

http://www.diyaudio.8m.com/Laf/Lafse2.html

Don't let the modest output power dissuade you from trying these out. With a well implemented power supply and decent OPT, these are very fast and dynamic, which can go a long way to sounding more "powerful" than the math would suggest, while retaining their musicality.

I personally preferred the EL84 design (with extra PS chokes and parallel feed output) quite synergistic with the stellar midrange of the FE108E Sigma in BLH.

To safely operate at sustained SPLs above 90dB, you'll probably need to pre-filter and roll in a pair of bass drivers somewhere in the neighbourhood of 80-120Hz. You could start with a cheap plate amp with adjustable turnover to find the sweet spot, and upgrade later to something like a LM4780 gainclone.

I found that I hardly ran mine at peaks approaching 90dB, so 5-10W of SE (T or P) was quite adequate, and very "creamy"

Guijs

Thanks Chrisb!

I'm about to order my FE108ez, but I have another question in my mind: This driver can do well with complex music like Rock (Eletric guitars, drums, like Dire Straits or even Rush) ??? I don't say a full orchestra concert because it's not my kind of music.

doorman

Guij: I listen to a wide variety of stuff incl. prog rock, jazz, orchestral, etc. These little drivers do an excellent job of sorting out the textures and nuances of the music. FWIW, they also go louder than my FE167E's, 'though I'm no headbanger. Aside from limited bass, you can't go wrong. Don

Guijs

Thanks Doorman!

This is what I want to read! Let's see if i'll need a subwoofer... My room is small.

Guijs

Just ordered my FE108ez on saturday. Can't wait to try it!

Rodeodave

Hi there!

Interesting post. I am about to build :smash: the Fostex recommended enclosure for the fe108ez as well. I'll build it out of 16mm MDF. I got the pieces cut in a "Baumarkt", that's a chain of hardwarestores in Austria where you usually buy tools and bathtubs and stuff like that...the MDF and the cutting cost me around 60$ (51EUR) for both enclosures (~4 m^2) and looks really staight, rectangular and accurate. We'll see...

The next step will be that I will slightly sand (240 grain) the surfaces that were cut, because there the fibres are not so compact (the fibres are ripped by the saw); sanding closes the surface. But I certainly won't sand the edges, don't worry...

Then I will "soak" every single piece with some undercoat (I don't know if the translation is correct; primer is another possibility), to seal off the MDF. Probably I'll use some 2-component undercoat because these can be spray-painted afterwards. The procedure should be like coat, let it dry for at least 12h, slightly sand (just smooth the surface, 240-280 grain), coat again, dry, slightly sand.
If one likes a coloured primer can be used, so later scratches in the paintjob are not that nasty...

Then I'll glue everything together with some waterproof glue. :att'n:
People have told me that this (waterproof) is important becuase the pait could dissolve or reject from a surface where some glue is on. (it can dissolve the glue, not the surface...)

I hope you guys can give me some advice for the assembly, I've read something about some japanese instructions....please.

I'm not sure if I'll use nails or srews or just glue alone (shoul do fine, there's a lot of surface due to the many parts), but if, there is some levelling (again, not sure about the translation...) to be done because noone would want to see nails or scewsheads under the paint.

Well, then there's the paintjob...no idea yet. Maybe spraypaint and some clear coating.

The sand will most probably be put in some kind of bag to avoid a mess.

So, after sharing my thought, I've got a few questions:

What will you be using as dampin material? Filt mats, that white stuff (don't know the name, like glass-whool),...?

How will you mount the driver? Directly to the wood or with one of these brass rings or ?

Do you think it's clever to direct-mount the speaker-cables to the driver or should i install a connection-port?

And for piece #29: There would be enough space in the cutting plan to make them whole pieces (two per speaker), right? I have no idea why they are cut into tinier pieces and don't fit the width...

What do you think about making round edges (pieces 3,4,5,6,12,...) and round corners inside of the enclosure, could this reduce unwanted resonances? There are sure a lot of parallel planes inside...

Well enough this time.

c u , dave

robertG

This driver is a really good choice!

MDF is not so good to construct the horns, but since you plan to seal the fibers, then it should be as good as birch plywood.

You will see that MDF "drinks" a lot!

Now, two things about the sealant:

1. Make sure it is compatible with the glue you will use;
2. Probably best would be to mask the areas where the glue will be applied, before sealing the MDF. Glue needs to soak a little in the MDF for tight bond (especially on the edges).

I would suggest that to do all construction work, except the last side panel, without sealant. Then when everything is glued and dried, apply as much sealant as it will absorb. Shellac is a very good product (but incompatible with urethane paints - test before!!) to seal wood. If it does not work, use a compatible product such as a sanding primer (2 or 3 coats).

For construction you can use glue alone, if you have plenty of clamps of different sizes. If not, you can use glue and brad nails (you probably can rent one along with a small compressor - works wonder and cost little).

For damping material, if you can afford it, use only high wool content felt (usually 95% wool) 10mm thick. Depending on wool content and thickness, it can absorb up to 80% of frequencies centered at 520Hz with nice roll-off. This stuff is MUCH better than any fiberglass material.

I do not know where you are located, but gemmeaudio.com in Canada sells the 10mm wool felt.

Several pieces are smaller than what they could be on the Fostex plan (this is to use every possible waste bits). You can use full width panels.

If you can afford the brass rings, use them. They provide mass loading on the driver frame and it improves sound focus. Plus it gives you a bit more compression chamber volume for you to tweak.

Sand should definitely be put in bags. Make sure the sand is dry (one hour at 100 or 200 degree in the oven should make it dry). You alson can use pebbles, rocks, ball bearings, etc. Anything dense, inert and heavy will do. Some people will pour melted paraphine on pebbles to make them "stick" together.

I'm not sure about the rounding edges on internal parts. Some people say it should be done to reduce turbulence while some other say you should leave them square to induce surface turbulence (which acts as a "lubricant" for air flow).

I would leave them as is, but then again I might be wrong because i did not do any turbulence analysis of the design.

Good luck with your project and I'm pretty sure you will be blown away by the performance of this little driver!

Craftsman

Hi Guijs,
Remenber when i told you about my BLH ??
Yes, They are Buschhorns. Understand now ?
I did some mistake, but our foreign friends speaks to me.
Take attention. This guys are so good.

:D PLAY A FOSTEX FOR REAL :D

Guijs

Those Brass Rings from Fostex are too expensive!!! Would a solid metal DIY ring, do the same job? Why the Brass rings are so expensive?

The FE108ez arrived on monday for me, and they are amazing. I'll start building the Fostex recommended enclosure next week.

Thanks for all the Help guys, this topic really, really help.

planet10

quote:

Originally posted by robertG
I'm not sure about the rounding edges on internal parts. Some people say it should be done to reduce turbulence while some other say you should leave them square to induce surface turbulence (which acts as a "lubricant" for air flow).

The steps in the Fostex design are intentional -- no rounding is recommended.

dave

Ghangis

Hi, I just completed a pair of backloaded horns using the F206e.I experimented with a super tweeter but didn,t notice much of an improvement.These are excellent speakers with this cabinet design but sound best with tubes.I found too much harshness and shout with solid state.Don't require much power as well.10-15 watts.Currently running them with an Eico HF-81 and they sound awesome.EL84 output tubes.

Scottmoose

quote:

Originally posted by Guijs
Those Brass Rings from Fostex are too expensive!!! Would a solid metal DIY ring, do the same job? Why the Brass rings are so expensive?

Because they are a company who wishes to make money, and this is a very good way of making some more.

To be fair economies of scale do come into this -they won't make / sell vast numbers of these brass rings, so that will push the price up. They're beautifully machined too. You want real extortion? Look at the prices of their plasic grills. Your wallet will scream for mercy, whilst you scratch your head and wonder how moulded plastic can cost so much.

A solid metal DIY ring will do the same job if made out of brass, which is not a particularly expensive metal. A change in metal type would affect the resonant quality though. I'm not a metallurgist except when talking about bronze and iron-age swords, which are another of my interests (well, I am a military historian!), so I'll let someone else work that one out. From my sword-making experience, I would favour bronze myself, but that's just me. The resonant frequency will shift, of that I'm sure, but which way would depend on the metal, how much is used, and which drivers you're using etc.

Best
Scott

kenev

quote:

Originally posted by Ghangis
Hi, I just completed a pair of backloaded horns using the F206e.I experimented with a super tweeter but didn,t notice much of an improvement.These are excellent speakers with this cabinet design but sound best with tubes.I found too much harshness and shout with solid state.Don't require much power as well.10-15 watts.Currently running them with an Eico HF-81 and they sound awesome.EL84 output tubes.

Which design did you realised?

10-15 watts might be more than enough for those horns. I think that even a 4 watter would make them play loud enough.

Ghangis

The cabinet I used can be found on the Fostex site under recommended backloaded enclosure for FE206E.I think you're right about the watts required.I can email you the plans for the cabinets I built if you need them.Email me at kevinl@maple.ca if you want them.

kenev

quote:

Originally posted by Ghangis
The cabinet I used can be found on the Fostex site under recommended backloaded enclosure for FE206E.I think you're right about the watts required.I can email you the plans for the cabinets I built if you need them.Email me at kevinl@maple.ca if you want them.

Thanks for your offer. I'm already aware of Fostex's horn design. As I wrote at the begining of this thread, I have decided to build Ron's Dallas II horn.

Evangelos

weidok

quote:

Originally posted by kenev

Thanks for your offer. I'm already aware of Fostex's horn design. As I wrote at the begining of this thread, I have decided to build Ron's Dallas II horn.

Evangelos

Why the Dallas II.. ??

weidok

quote:

Originally posted by Scottmoose
You can't use the FE167E in a horn, but the 166 is a popular option.
Scott

What is wrong with using the FE 167 E in a horn ??

serenechaos

quote:

Originally posted by weidok
What is wrong with using the FE 167 E in a horn ??

Some people use FE167Es in horns (high-end ones at that) to very good effect. see:
http://www.decware.com/newsite/cornerhorn.htm

The FE166E is usually recommended though as it is pretty much the same speaker with a larger magnet, instead of a being shielded.

Horns like high Fs/Qts ratios.

Robert :)

MEX

Look what I found... ahahah

Guijs, have you started yet your BLH?? I'm very anxious for a review.

I've seen a page that were made a cabinet with 12 fullranges drivers... that surprised me. When looking for details I found your topic here.

Good Luck!

MEX (STF)

Guijs

Hello MEX :D !

I'll start to build my BLH on the next weekend! The wood pieces are ready.

Intersting this cabinet you said... a Line array with Full Ranges?

MEX

Yes... actually the owner doesn�t specify if the driver is a fullrange or not. But I�m quit sure the it is.

He used a Ribbon tweeter for the higher frequencies and twelve drivers. It�s quite strange, but seems interesting...

Don�t you know?
http://www.mrweb.com.br/fvm/
SPEAKERS -> L.A. Fidelity

It�s in portuguese, sorry guys...

MEX

eLarson

Tudo bem.

Rodeodave

Hey Guijs,

how's your project doing?
I think we're on the same project. I'm building the Fostex recommended enclosure for the FE108EZ.

Started last weekend and had like 1-2 hours per day this week for glueing things together...pretty much straight forward. One Speaker is almost done (like 7 to 8 hrs work). Will hopefully finish by the end of next week.
The fun part is, you can put it together without really checking if everything is in the right place (like right distance from each other...), because only two parts (5, 22) are not connected to any other parts which would hold them in place.

I started with the exponetial part in the middle, then with the lower part and finally the part where the driver is mounted.
I'm building it with 16mm MFD, which i will be sealing off before finally putting the three parts in the enclosure. The sealant makes the MFD really hard and almost shiny if you soak it well. I'm really looking forward to do the paintjob on such a surface.

I use waterproof glue, because the sealant is water-based (I don't like the smelly stuff plus the water-based stuff can dry in the apartement).

I decided to do the sealing after the glueing-stuff, because the plain wood can soak more glue that way; makes stronger bonds.

Hopefully I can post some picture this weekend.

Have Fun,

Dave

Rodeodave

Forgot something:

Will the FE108EZ mind being connected to a 4 Ohm output of an old, kinda crappy, but fun ECF80/EL86 10W tube-amp?

The amp has got a 12,5 Ohm and 4 Ohm output. The FE108EZ is rated 8 Ohms, as far as I know.

Guijs

Hello RodeoDave!

I'll start to build the enclosures tomorow, on the weekend. I've made a CAD drawing of the pieces and cut it with a laser machine! So the pieces are exactly perfect and you can do some rabbets like puzzle. I'll post some pictures on the sunday.

I'm using 15mm Naval Plywood, like the plan recomends. It will be very easy to build.

About your amplifier, the only thing I know is that you can use a 4ohms amplifier with a 8ohm driver, no problem. The amplifier will send half the power to the speaker.

I'll use a Pioneer receiver just to break-in the speakers, and after this i'll start to test some tube-amplifiers!

Good Luck

Guilherme

Guijs

I have finished the Fostex FE108ex enclosure this weekend. Tomorow i'll star the auditions.

One question: Did you guys round the speaker hole? Because with this little driver, I didn't feel that it have too much space for the air to flow nicely!

doorman

Yep, I always bevel the cutout on the back of the speaker baffle, takes so little time to do anyway. Will you post some pics when done?

Guijs

Well, I did it too. Not as much as I wanted, but I did. I have some pictures here, i'll post wne everything is done.

Thanks

planet10

We usually clear as much space as possiblt to enable airflow from the back of the driver... usually a 45 degree angle... my newest ones thou -- with a 1/2" baffle & rebated to flush mount the driver didn't need it.

http://www.diyaudio.com/forums/show...1378#post731378

dave

Rodeodave

Hey Guijs,

can't wait to see the pics...:bigeyes:

I hope that I'll finsh mine by the end of the week.

What kind of damping material did you use? And how much?

Guijs

Here are some pictures of the construction!

Last 2 pictures is just an improvisation! I'll make a better fisinh on the wood later, and i'm preparing the shelf to receive the loudspeakers.

Embalando pra terminar em casa...

Rodeodave

WOW! Nice work!

Didn't know that plywood can be laser-cut...impressive.

A few questions:

The cavity below the driver will be filled with sand, right?

What damping material did you use? Looks like some kind of foam-thingy...

I can see that you are using the original parts (#29) to fill the compression-chamber. Are there spaces between them so that they fit the 170mm? I'm thinking about using two 170mm wide pieces instead. But I'm not sure yet...

What do they sound like?

planet10

What is th epurpose of the big cavity at the top?

dave

Guijs

Rodeodave,

Yes, that cavity is to fill with sand bags, i'm doing it right now!

I used a foam on the front wall as you can see, but in the botton (in my case is the top) I used a long fiber damping, like a cotton. You can't see it on the pictures.

I used the #29 pieces, with spaces between them. You can see it here.

The sound, listening in the way that you see on my last picture, with no sand bags, I found that the highs are very clear and detailed, and so as the midrange! I notice that they get better during the first auditions! The bass is weak, but In this condition I cannot demmand much more from the bass.

I'm very satisfied by until now! If i'm linking the sound with this Pioneer receiver and old LD player, I can't wait to hear this with a single ended tube amplifier and a Hi-end CD player or Vinil!

Planet10,

That cavity is on the bottom, not the top. The enclosure will be on a shelf, so it needs to be upside down! The box is 20cm higher from the original project, so the speaker will be in my ears level. The cavity will be filled with sang bags.

I'll post more pictures later.

Thanks for all the help guys!!! Very much!

Guilherme

Guijs

Here is the picture of the enclosure on the shelf:

planet10

quote:

Originally posted by Guijs
That cavity is on the bottom, not the top. The enclosure will be on a shelf, so it needs to be upside down! The box is 20cm higher from the original project, so the speaker will be in my ears level. The cavity will be filled with sang bags.

I saw the pic below before your response... it was all i needed to understand completely.

dave

Guijs

Guys,

As you can see how my speakers will be disposed in the room, do you think that i'm doing right going with the original Fostex plan, or it will be better going with the Bushorns mkII?

Guijs

I'm asking because I feel a bit of lack bass output. Maby to early to wory about this? :D

planet10

quote:

Originally posted by Guijs
As you can see how my speakers will be disposed in the room, do you think that i'm doing right going with the original Fostex plan, or it will be better going with the Bushorns mkII?

I can't comment on the horns you built, but my experince with the one Fostex horn i did build has not been outstanding (i haven't given up on it).

The B-Horn II is a known entity to me. I know it works well.

As to bass. The 108es needs a couple hundred hours on it before its bass comes to the fore (and it will never produce lots of bass in the B-Horn or the Fostex. When fresh you should expect very little bass. The lack of bass is what is promting Chris & i to come up with a new design that is closer to a consistent horn than the TL/Horn hybrids that the Fostex & Buschorn represent -- the Qt on the FE108ES is quite low.

dave

PS: a current amp would help in the bass, but you might soon run into excursion issues. What amp are you using?

Guijs

Dave,

I changed the cheap optical cable I was using by a cheap Analogic RCA cable and the bass got better. You're right, I need to wait for the speaker to burn in before worry about BASS.

I'll wait for the speaker break in and then i'll test some tube amplifiers. If I still feel that I need more bass, i'll try the Buschorn mk2.

PS: "Current amp" do you mean a tube amplifier? At the moment i'm using just a Pioneer RECEIVER with an old LD player. I'll use these equipments during the break in period, and then start to try some tube amplifiers.

Thanks

planet10

quote:

Originally posted by Guijs
Pioneer RECEIVER

That is not going to do it....

A no-feedback SET amp tends toward being a current amp (Chris' EL84 parafeed (in triode or RH mode was beauty with the FE108ES in B-Horns), a SEP or PP Pentode amp with no feedback is decidedly a current amp.

dave

Guijs

Next week I'll try 2 different tube amplifiers: One with 3wrms/ch and another 30wrms/ch, I'm almost certainly that both are pure triode.

The receiver is just to burn-in, I can't wait to get a descent amplifier...

Thanks

doorman

Dave is right, the B'horn's bass is quite good, but definitley not earth shaking. Having tried mine with both tubes and ss, the tube amp is MUCH better. Good Luck!

Alexandertol

quote:

Originally posted by Rodeodave
I can see that you are using the original parts (#29) to fill the compression-chamber. Are there spaces between them so that they fit the 170mm? I'm thinking about using two 170mm wide pieces instead. But I'm not sure yet...

Hi,

You can use just two 170mm wide pieces. I did it also like that. The only reason the used the 6 pieces instead that they didn't fit in the original cutting plan.
Hope to see some pictures soon.
Here are some pictures of the speaker I build.

Alexander

Alexandertol

Hi,

And a picture when my project was finished.

Alexander

Guijs

I do not want earth shaking bass. But i now that I feel this lack of bass because the driver is very new, and I'm playing it with a poor amplifier. I'll have a tube amplifier very soon to run these babies!

Do you guys thing that the B-horn will work upside down?

planet10

quote:

Originally posted by Guijs
Do you guys thing that the B-horn will work upside down?

You'll miss the floor loading it was designed to use....

dave

Guijs

My amplifiers are decided for the FE108ez in Fostex recomended. Will be a pair of tube 30w p/ch monoblocks with EL34 in pentode. The Pre-amp will be tube too. I heard the sistem wirh this configuration and simply loved it!

Comments?

planet10

quote:

Originally posted by Guijs
a pair of tube 30w p/ch monoblocks with EL34 in pentode... simply loved it!

And when you get a hankering for more... those will make a REALLY good 8-10W Class A differential amp (EL34 in triode or 2A3s)

dave

Guijs

What subwoofer to use with the FE108ez?

I'll cross it about 80-100hz with a active crossover, and let a woofer do the BASS job. I have a automotive sub JL 12'' W0, and a pair of NHT 10'' subwoofers.

Wich kind of enclosure? Sealed, ported, TL?

planet10

quote:

Originally posted by Guijs
What subwoofer to use with the FE108ez?

Wich kind of enclosure? Sealed, ported, TL?

Sealed, TL, or aperiodic. You want something that is quite extended at the top -- a woofer rather than a subwoofer.

dave

Guijs

Planet 10, any suggestions?

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