Bottlehead Forum
Other Gear => Speakers => Topic started by: Noskipallwd on September 13, 2011, 07:17:24 AM
-
Hello, a couple questions for those who have, or have had Fostex drivers. Planing on building my first pair of full-range horn speakers. I am considering the Madisound BK-12M kit, due to price and a small listening space. I also don't feel comfortable building the cabinets from scratch at this time. The kit uses the 4.5" FE126en driver. I will be driving them with a 16 watt PP amp for now but plan on building the Steremour soon. Would these speakers be a good match with the steremour, and would they benefit from the addition of a super tweeter such as the Fostex T90A? Thanks for any advice!
Shawn P.
-
The FE126E (I assume the -EN is similar) is rated 93dB, which by itself is satisfactory for most purposes with a 2A3 amp. (For a serious assault on orchestral music, especially in a large room, I'd like to see 96dB.)
It's a pretty small driver, so it will not likely go extremely loud without distortion no matter what power you have on hand. I doubt that you would benefit from more power than a Stereomour has to offer.
Because the BK-12 is a back-loaded horn, it may be more efficient in the bass, and hence get louder than the 93dB midrange rating suggests.
Tweeters used with these type of drivers are usually super-tweeters, crossing in for the highest octave only. They will add some air, but will also muddle the point-source character. It's a crap shoot which any one person will prefer. You'll just have to try it and see.
-
Thanks for your reply Paul, yes the EN is rated at 93db. So, if I were to use a super tweeter all I would need for the xover would be a cap? If so how would I determine the value?
Thanks again,
Shawn P.
-
Hi,
You might be interested in the Mark III Frugel-Horn
<http://www.frugal-horn.com/>
I think I am going to build them for my secondary system and just because they look cool.
-
...So, if I were to use a super tweeter all I would need for the xover would be a cap? If so how would I determine the value?...
That's what a lot of people do, and it's simple enough that that is where I'd start if it were me. Actually, I'd use a cap feeding an L-pad so you can adjust the level and cut-in frequency independently.
Choosing the capacitance is not as simple as it seems. The cone will have close to adequate frequency extension, measured on axis; it's the job of the tweeter to fill in some more off-axis energy (some call it "air") and perhaps to give a cleaner treble, free of Doppler distortion and cone resonances. Making that balance is a matter for listening, not for calculating. You can spend endless time on the internet getting reams of conflicting advice, or you can experiment. Obviously I'd go for the latter!
For 8 ohms, 2uF is a -3dB point of 10kHz and would be a reasonable place to start. If you want a suggestion, get a pair at 1.8uF and another at 1.2uF. That gives 3uF in parallel, 1.8, 1.2, or 0.72 in series. Between these options and the level control, you should have many happy weeks of careful listening. Get inexpensive polypropylene caps, Solens or similar, and ask Grainger about breaking them in before you make any long-term judgements. Once you have narrowed it down, then it's time to look into better caps. Same goes for tweeters, IMHO.
-
Paul thanks for all your help, I think a L-pad is a great idea. Experimenting is alot of fun! Thanks for the link to the Frugal Horn, Thoburn, they do look interesting.
Shawn P.
-
I have the Fostex Fe206en's in a Madisound BK-20 cabinet. I originally used a pair of supertweeters , but as time went on I found I liked them better with out them. i used a 3uf capacitor and a L-pad.
At first I found them a little shouty and not very smooth. I put some small pieces of foam between the whizzer cone and the main part of the speaker. They also needed a very long break in time over 300 hours. With time and the foam they sound much smoother to me now.
Debra
-
Debra, thanks for your reply, I've decided to buy and build the BK-12M stock and give them an extended burn-in, then I'll know if I want to try the super tweeter. I will try the foam behind the Whizzer cone though.
Cheers,
Shawn P.
-
I will try the foam behind the Whizzer cone though.
The FE126En used in the BK-12m does not have a whizzer cone to put foam behind.
A buddy of mine has some older Omega speakers that used the similar Fostex 127E in a reflex box.
-
Shawn
If you go with these let us know how they sound. I was thinking of building a pair for a secondary system.
Debra
-
Hello,
Hey Wanderer, your right about the whizzer cone, did your friend like these drivers in a Bass reflex cab?
Deb I will surely give you my impressions, after I've had a chance to build them and have some quality listening sessions. I plan on ordering them this week, I work 7 on and 7 off in a Hospital lab, so I would like to time their arrival just before my time off. I was at the DIY audio forum recently and apparently the cabinets were designed by the gentleman from Planet 10 Hi-Fi who is responsible for the Frugal-Horn. Grainger gave me some good tips on breaking the drivers in, looking forward to it. Finally finished my Crack bulild, and our fellow Bottlehead HF9 built a great new cable for my HD 650s, so I have spent most of my free time listening to some great records I have not spun in awhile, anxious to hear how they sound on some great gear.
Cheers,
Shawn P.
-
Hey Wanderer, your right about the whizzer cone, did your friend like these drivers in a Bass reflex cab?
My friend is using them with a older hybrid Musical Fidelity amp. He likes them, but I found them like a girl I used to date in college, Hot, Thin and Harsh.
I don't think these Omegas used any baffle step compensation ("BSC") and sound too treble forward to me. I have since talked my buddy into trying an inexpensive small Sony servo "sub"woofer Amazon had on sale for next to nothing. Adding a little "thud" to the bottom end tended to warm things up and he now likes that sound better.
Back horn loading should take care of the BSC and has the potential to sound more ballanced sans add on helper woofer.
-
I know this is getting a bit old but ... I have a pair of older Fostex speakers, and cant remember the model number. I was to say FE207's but not sure. They are shielded as at the time they were going next to a CRT television (10 years ago atleast now). Anyway, I built double bass reflex cabinets for them. I used Damar varnish on the cones if memory serves. I also placed a fairly efficient tweeter on the back of the enclosure. Cannot remember the cap value I used. The tweeter is not on an L-pad and I got very lucky with it. It really doesnt add any treble extension that you can notice but just adds the very slightest bit of "air". Anyway, yes they take a long break in. They are connected to one of the original version S5 amps (cheap push pull kit amp) with a tube CDP as source or sometimes swapped over to the DIY Tube 35. I have no idea what measurements would show, might be a mess but they actually sound really good with solid bass. Although not extended I never felt like I was missing anything with the blues and rock that I mostly listen to. I liked them so much that I was looking into doing something with the Sigmas but found a pair of JBL LE8TH's (need a re-foam now).
Fostex drivers are great, especially for those on a budget looking for the single driver experience. Several models always seem to have real good potential and someone always seems to come up with good enclosure designs for them.
-
Laudanum, a cautionary note on the LE8-Ts. There are I believe several after-market replacement foam suspensions, but they have ***four times!!*** the stiffness, and raise the resonance frequency by an octave (and double the QT).
Try to get a real JBL kit installed. Those kits typically are "out of production" then every few years they make a batch of them and they are available again for a year or two. They are not cheap, but nothing else works. You can sometimes get kits to re-cone them as 2115s instead; a little more efficient and less flat response.
-
Thanks Paul. Im probably 1/2 hour away from Speaker Exchange in Tampa FL. I've spoken to them a couple times about it but was more concerned about the dustcap. I dont know if you know who they are but they are pretty well known and have been around a long time. They can do the re-foam without replacing the dustcap. I also inquired about surround materials wanting to avoid butyl rubber and stay with foam which also isnt a problem. But I didnt know about needing the specific JBL foam to retain stock parameters. Makes perfect sense though as that foam was really "soft" for lack of a technical term. Thanks so much for mentioning it. I will have to give them a call again. I know that they know JBL so I may just need to talk to someone there who has been around a long time but Im a bit miffed now that they wouldnt mention it. Hopefully it may have just been who I talked to not knowing. These arent the alnicos but they are still great speakers. I use them as extended range with a fostex FT17H capped and through an L-pad. Ive had them for 10 years, they are dropped into large vented enclosures. They are my favorites. I may be best off trying to find the JBL re-foam kit and then brining them in with it, even if I have to wait for production.
Thanks again Paul, you probably saved me some heartache.
-
Yeah, I think that 99 out of 100 owners of LE8-Ts are shocked at the JBL kit cost and simply refuse to get it - and get angry at the dealer who tries to sell it to them. So, many won't even mention it. In a lot of cases, these were just ceiling PA speakers - that's how I acquired four of the alnico ones :^) New surrounds come with a new cone, voice coil, and dust cap - that's worthwhile because the aluminum dust cap has a foam damping parch on the inside, which is probably in as bad shape as the surrounds. I spent something like 10 times the purchase price to get them re-coned.
-
oh-oh ... how much does JBL charge for the kit for a pair if you dont mind me asking?
Thanks
-
Yeah, I think that 99 out of 100 owners of LE8-Ts are shocked at the JBL kit cost and simply refuse to get it - and get angry at the dealer who tries to sell it to them. So, many won't even mention it. In a lot of cases, these were just ceiling PA speakers - that's how I acquired four of the alnico ones :^) New surrounds come with a new cone, voice coil, and dust cap - that's worthwhile because the aluminum dust cap has a foam damping parch on the inside, which is probably in as bad shape as the surrounds. I spent something like 10 times the purchase price to get them re-coned.
WTF?!?!?!? Have I ever heard these? Did you ever put them in an enclosure and hit them with signal? Oh, the inhumanity!
Sorry, just coming off a day of moving a few parts of a Hammond model E organ/speaker complex, including two D-20 speaker cabinets with two each Jensen A12 field coil drivers. So I'm in the "vintajjjjj" mode.
-
No, they are still sitting in their shipping boxes. Two are LE8Ts, two are reconed as 2115s, plus I have a pair of D-208s - all 8-inch fullrange JBLs. Never had a suitable box. Needs to be, oh, about the size of the Thrasher, actually... :^) Seriously, I think I'll get a pair of those.
-
Hello again,
Thought I would give an update. By the way, I think I'll avoid the JBL LE8-Ts. I built The BK-12M kit, it was an easy build, the cabs went together well. Just make sure you have enough bar clamps! I have not done any finishing, still just bare Baltic Birch. Well, right out of the chute the Fostex drivers were harsh and shrill. Kind of like a neighborhood cat in heat. So I ran Graingers break-in method using my music server and gainclone. After 60 hours or so the Fostexs began to settle down. So I have done some listening with my cheap PP 16 watt amp and I have to say I am glad I decided to get this kit. Soundstage is excellent, they fit my listening area well. Lack in bass, but that was expected, and I don't think I will need to add a super tweeter. Symphonic, as well as vocals perform well on these speakers. I might look into adding a subwoofer for the Bass, although I am happy with classical and jazz as is. Now I need to build a Stereomour or some Paramounts so I can drive them properly!
-
I think you will find with even more time they will sound even better.
It took mine almost 300 hrs before I was really happy with them (mine are fe206's)
Enjoy them
Debra
-
Shawn,
Any more updates? Having been through three iterations of another very similar design I can confidently state that these need a good 400 hours to break-in, but continue to improve slightly for probably double that length of time.
I don't know the design, but if there is an empty sealed chamber near the bottom, you can fill it with BBs and sand, or just a lot of BBs and that tends to make things even smoother and the bass still better.
You could also bolt them to a heavy maple block -- the michigan maple 12" x 18" x 4" ones work really wel and aren't terribly expensive -- they are just maple cutting boards.
These look really interesting, and an awful lot of speaker for the price. I may just have to build a set to see how well they do with the s.e.x. and stereomour as I'm always looking for reasonable, high-value, decent sounding speakers for friends on a tight budget.
-- Jim
-
Hey Jim,
I have put alot of hours on the Fostex drivers lately, I recently aquired a Jolida tube phonostage and have enjoyed running my LP12 and Concept through it.
Shawn,
Any more updates? Having been through three iterations of another very similar design I can confidently state that these need a good 400 hours to break-in, but continue to improve slightly for probably double that length of time.
Yes, the SQ is continually improving, and I have finally settled on the best placement for them. The soundstage is already excellent, now I understand the single driver thing. Well recorded symphonic vinyl sounds fantastic through these.
I don't know the design, but if there is an empty sealed chamber near the bottom, you can fill it with BBs and sand, or just a lot of BBs and that tends to make things even smoother and the bass still better.
There is a small triangular space there, I'll have tap into it and give this a try.
You could also bolt them to a heavy maple block -- the michigan maple 12" x 18" x 4" ones work really wel and aren't terribly expensive -- they are just maple cutting boards.
They say great minds think alike! HeHe, actually I built stands for them using 1" square steel tube stock for frames with spiked feet in the corners. I bolted 2" thick maple cutting boards on top of the frames and the speaker cabs to those. They lifted the drivers to a better listening height, but the SQ change has been fairly minimal so far.
These look really interesting, and an awful lot of speaker for the price. I may just have to build a set to see how well they do with the s.e.x. and stereomour as I'm always looking for reasonable, high-value, decent sounding speakers for friends on a tight budget.
-- Jim
I would recommend these to anyone with a small listening area interested in great single driver full-range speakers that won't break the bank. They are a good bang for buck deal. I haven't been able to decide on how to finish them though, any recommendations?
Cheers,
Shawn
-
Shawn,
Finishing is always a matter of personal taste, but all kinds of possibilities are open with these because of the BB ply (which I think looks fine finished natrural, but can also be a lot of work, especially if using an oil finish on the end grain sections. Wipe-on poly also works well, as does veneering -- I veneered my last pair of Horn Shoppe horns with australian lacewood and they came out beautifully and now live with a neighbor who loves them. because the construction is not done with bevel joints and the eend grain is exposed, a good bit of sanding prep will be needed, and you should stick with paperback veneer and contact cement or a vacuum press and cold press glue -- raw veneer and heatlok glues will probably not hold up as well.
If painting, try to use one of the textured paints -- also because of the exposed end grain -- as the wood shrinks and swells, the textured paints will telegraph the seams much less than a glossy or even semi gloss paint.
All up to you, of course. but I think the textured paint can look really good on these and I'd probably do my pair in red instead of black, and Debk would probably do hers in purple :-). For me, a stain annd wipe-on poly would probably be the next choice -- all depending on the room it is likely to be used in.
My eldest neice will be 11 in January, which means the following year she will get her first stereo from uncle Jim, and these are looking like a very likely pair of speakers for her -- now I just have to find out what her favorite color is :-).
Thanks for the update and glad to hear they're doing so well.
-- Jim
-
Just discovered you post. I have Hornshoppe Horns, which use the Fostex FE126EN driver.
They play extremely clean. A couple of tube watts can play them above 110 db without distorting. Though I don't play them that loud, I have tried it, just for the fun of it. I also added a Fostex T90 Super Tweeter which even enhances the sound of the Horns. Secret is to cross them over rather high, like at 35 khz, using a 0.33uf cap. This way the Supertweeter does not add anything in the frequency the FE126 plays, but it 'continues' the upper Frequency response, which lets you see much deeper into the acoustical scene. Having the Supertweeter, I no longer would want to live without it.
-
Regarding JimR's post on veneering raw BB plywood (such as the Madisound BK12 kit) - I've built more than a few dozen pairs over the years using the iron-on wood glue technique with quite satisfactory results (including the Macassar Ebony enclosures for Jim's Fostex F120As a couple of years back)
Aside from the most obvious issue with contact cement - no room for adjustment, there's also the potential for solvent based stains/finishes to penetrate paper backed or pure veneers and delaminate solvent based contact cement.
Yes, the butt joints and exposed edge grain will need good sanding and a glue-size pre-coat to eliminate telegraphing through the veneer, but at the end of the day, it's no more work than proper prep for a paint job, even when applying textured products.
The BK12 has two small triangular cavities at the top of the fold and a slightly larger one at the bottom - filling those with BBs, crushed glass blasting media, sand etc certainly can't hurt.
As the mouth on this design is forward facing, it won't benefit from boundary reinforcement as do the Hornshoppe, FH3, or any rear mouth BLH.
-
Chris,
So is the BK-12 the same basic configuration as the bk-16? Sounds like it, in which case my recommendation for filling with BBs probably won't do all that much as compared to the sizeable void aat the bottom of the Horn Shoppe horns.
From what many bk-16 builders said, an extra layer of 1/2" or 3/4" ply on the sides was a pretty useful addition, which probably means a 3/8" extra layer on the sides of the bk-12 might be a good thing.
As for the veneer, I suppose whatever each person is comfortable with is fine but I'm mostly trying to stay away from veneer and paint these days myself.
I would still however, stuff the triangular voids with something -- felt, or whatever, just to cut down on resonance, but not having heard this speaker, I don't even know if that is an issue.
I will really just have to get a pair of these -- they really look like they have a lot of potential, especially for te price -- less than $400 total for a sweet liittle floor standing speaker is somethig that has a lot of appeal.
-- Jim
-
I've been looking into the FE126EN too lately. I want to sell off my Axiom M60Ti to build a set of Saburo horns.
I don't know if it's the right step over what I currently own, but I love the way they look and I like the idea of building it with my own two hands.
I keep imagining what the Saburo would sound like with tubes :0)
-
Hi to all on the forum. This is my first post here. Three days ago, I completed my first speaker build, a pair of the BK-12s. I am very pleased with the sound so far. They just sound great, and the bass is amazing for a 4.5" driver. I am driving them with a home built Zen4 from the PassDIY site - I love the amp, have had it for about 5 years now. I have a foreplay3 on order to go with the system, no decent preamp now, and the Zen really needs one. The placement and orientation of the speakers in the room is seems critical...but the room is very odd shaped.
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fralphhowey.com%2F_audio%2F_images%2Fspeakers-1.jpg&hash=a45401a7ca69f7d8789457c4ed2270b899e07de0)
(https://forum.bottlehead.com/proxy.php?request=http%3A%2F%2Fralphhowey.com%2F_audio%2F_images%2Fspeakers-2.jpg&hash=384f0bae6e38078d6815ccc6ae31216ac94d7f3d)
-
Nice work.
Give the driver about 300 - 500 hour break in time to hear the full potential of the speaker.
-
Have not checked in on this thread in a while. Ralph, I like the way you finished those, mine are still naked. Yes, these speakers require alot of attention to placement, and are best suited to a small listening space. They do take a long time to settle in. Chris, and Jim, I put some steel sandblast media in the bottom space of the cabinet. Although very subtle it seemed to improve the clarity of the bass and mids. All an all they are great little speakers, I'm driving them with the first amp I ever built, a S5 electronics K16l push pull integrated. Considering they sound good driven by this amp, I can't wait to see how they perform driven by a Stereomour or some Paramounts!
Cheers,
Shawn P.
-
Thanks for the compliment on the finish. I got a little bit of glue on the "end grain" of the plywood that is visible from the front - will tape off some areas on my next build. After almost 2 weeks with the BK 12s I really love them for most of my music. They excel at jazz, folk and acoustic blues. Not as good with the "old" rock I listen to on occasion. Very curious to see what difference adding the Foreplay III to the system makes.
Then maybe another system for the times I feel like rocking out. Hmmmmm.... NP's BA3, or a PP tube amp
The possibilities are endless...
Ralph
-
I would agree with Catp.Z, the Fostex drivers seem to need a lot of break-in. I'm using the FE-166's in the BK-16 cabinets. Basically, the same thing just a scoonch larger all around. I have a pretty small listening room, as well.
I built mine two years ago and broke them in for 50 hours thinking that would do it. They sounded pretty good after 50 but just kept getting better. Every now and then, I'd play an album that I hadn't played and I was taken aback by some detail I hadn't noticed the time before. I'm currently driving them with a Foreplay III (stock) and a highly modded SEX amp.
They are part of my Heaven.
Someday, I may just have to build some horns for the 8" 206e's.
Looks like you did a great job on your build. You will get a lot of positive comments on those. Mine certainly start a lot of conversations.
-
I have to say that the existence of this kit really pleases me, serving a clear need to the community. It'd be nice to hear some some time, if anyone in the PNW area has them done.
Cheers,
Clark
-
I've been seeking out an easy first speaker build project and the BK-12M looks like a nice starting point. I currently use Blumenstein Orca's so I'm familiar with the fostex fullrange drivers and how lovely they can sound. My other thought is jumping up to the BK-16 if there is a significant benefit in frequency response.
I would assume the bass on these are good enough for acoustic genres of music like folk, jazz and classical but would benefit from an active sub? I like the idea of having separate speaker systems which focus on specific genres of music. Something I learned during my years of buying and trying headphones is there is no one can that can do it all perfectly.
I plan to drive them with either my Bottlehead SEX 2.1 or Stereomour feed by my Hagerman Bugle2 phono and Rega RP1.
Thanks!
-
No, they are still sitting in their shipping boxes. Two are LE8Ts, two are reconed as 2115s, plus I have a pair of D-208s - all 8-inch fullrange JBLs. Never had a suitable box. Needs to be, oh, about the size of the Thrasher, actually... :^) Seriously, I think I'll get a pair of those.
Paul, LOL. lets do it (!)
-Clark