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graeme uk 18th May 2006 09:47 AM

which fostex driver/enclosure should i choose?
I want to build some speakers, its the first time ive done anything like this.
At the moment i am using a modded quad 44 power amp (100w)
and a pair of mission 733 floor standers.
I fancy building a full range horn, what can i expect it to sound like compared to my missions?
Because its my first build, for ease im going to use the recomended horn enclosure recomended by fostex for the particular driver, unless anyone has a better recomendation, but which driver should i choose?
Im not looking for huge volume, im more after clarity and detail at normal listening volumes.

Any advice appreciated.

P.S. stupid question this but just to make sure, as its one cone, full range, i assume no crossover ect in needed, just speaker wires connected to the terminals on the driver?

sreten 18th May 2006 01:51 PM


rabbitz 18th May 2006 02:08 PM

Re: which fostex driver/enclosure should i choose?

Originally posted by graeme uk
P.S. stupid question this but just to make sure, as its one cone, full range, i assume no crossover ect in needed, just speaker wires connected to the terminals on the driver?
You still may have to add baffle step correction which uses a resistor and inductor.... in fact I found it absolutely necessary on a FE127E I recently completed.

Here's an example of a BSC circuit.

graeme uk 18th May 2006 03:42 PM

Thanx for the link, and the info.
I like what he's built in the link but why that inclosure rather than the fostex recomended enclosure?
I would have thought they know how to get the best out of their drivers.

sreten 18th May 2006 04:09 PM


it seems the BK201 design has been discarded by Fostex
in favour of a design that only uses right angled cuts.

IMO the Solo 206 cabinet is more like what rear horn loading should look
like than the latest cabinet design - which I'd describe as extremely crude.

I'd also describe it as a number of linked resonant cavities in series
rather than horn loading - which requires a constantly expanding
cross sectional area in my book.

Also I think the form factor of TGs design is much nicer, though
you could add a couple of inches to the width of his design.


graeme uk 18th May 2006 04:14 PM

yeah, i see your point.

Reading about these though, he says their best for valve amps, will they sound good with my 100w ss quad 405-2?
Also, he said there best with intimate jazz.
I like alot of different music, from jazz and classical, to rock and electronic.

Am i looking in the right direction for my new speakers?

I like my missions, but they sound there best at volumes too high for my neghbours and girlfriend, so i want to build a pair of speakers that will give me more clarity at lower listening volumes.
I supose if im only using a couple of watts of my available power, thats not so different from a low power valve amp?

sreten 18th May 2006 04:42 PM


i'd say you need better quality speakers, checkout :

May not go as loud as the missions with 100W, but with a well
made braced cabinet should eat them for breakfast detail wise.


no xo 18th May 2006 04:45 PM

My first horn project was the recommended horn for the Fostex FE206E and I like them better than my Proac Response 1sc`s, which are highly rated in most of the magazines and so forth.

chrisb 18th May 2006 04:56 PM

With the quantity of power you've got available, the sensitivity of any back loaded horn design would probably be less important than the synergy of amp/speaker combination, as well as room placement / WAF issues. .

The cost difference between the FE126 and 127 is minimal, and the latter driver is much more flexible in terms of enclosure design.

I've built or heard quite a few of the design variations in the "reference" thread using FE127s, as well as several horn designs with the FE126 and FE108EZ. (also quite a few CSS FR & WR125 variants)

While I've concluded my personal preference as a coin toss between 2 particular horn designs, (Ron Clarke's A126 and the freshly minted and still evolving FrugelHorn) it's important to consider a couple of factors:

I'm listening exclusively to low power tubed gear ( SE and class A P/P EL84 designs); particularly on either of the horn systems, a SS amp ( mini-Aleph classA 15W) sounds more detailed and analytical, and less emotionally involving.
With all due respect to the venerable Quad 405-2 amp, once you've experienced the synergy between hollow-state and FR horns, it's a whole 'nother ball game.

Proud poppa syndrome - as with many DIYers, I've built or tweaked most of the non-source components in both my audio and videa systems, so it's hard to be completely objective. A few months ago I had to donate my Denon AV receiver to my son, as it become fatiguing to watch TV on my Heil AMT/ Fostex speakers without tube amps involved.

Having said that, my mom and everyone who's heard them are quite thrilled with the performance and size/form factor of the folded mono-pole FE127. Dave (Planet10) can probably dig out the photos of same. They're just not very big, and unlike the rear mouthed horns, don't rely on corners for reinforcement of the lowest octaves.

And don't forget the Fonkens - not quite as stealthy or easy a build as the MLTLs, but superior performance.

Plans for all of these designs available at:

graeme uk 18th May 2006 05:27 PM

Hmmm, im getting confused now.
Luckily WAF in not a problem really, only approval of volume is a problem.
What speakers look like, how big they are, and where they are placed is entirely up to me.
Unfortunately im in temporary accomodation so cant say what kind of room they will be in next year.

I must admit im getting confused by all the different options available to me, should i be looking at something other than fostex drivers?

Im happy with my amp, the recent mods have helped lots.

I suppose my requirements are

Around 100 for drivers
quality, clear sound at low to normal listening volumes (if i want loud ill switch over to my missions)
Im no stranger to woodwork, so complexity of cabinets isnt a problem
Would be nice if they looked funky/retro/60's sci fi, but obviously that isnt exactly important.

I liked the idea of the fostex drivers as they seem good for the money.
I liked the idea if full range as it reduces the crossover requirements (electronics are still a bit of a mystery to me)
I liked the horn idea as i assumed it would improve the bass at low volumes.

So, horn or no horn?
Fostex or other?

Turning ito a bit of a general speaker thread now:D

Chrisb, you say synergy of amp speaker combination is the more important issue.
What speakers would give me good lowish volume clarity with my 405-2?


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