Fostex FE126En Build

[eldarvanyar]

Hi I am new to full range and have not yet heard one.

I have purchased a pair of Fostex FE126En speakers after reading various forums from Wilmslow Audio.

I have had some box's made to the Fostex Spec Standard Bass Reflex Enclosure 15mm Plywood with an Ebony Macasser veneer that I have been polishing with beeswax. They are from a trader on Ebay in Moldova and were a bargain in my opinion.

http://www.fostexinternational.com/docs/speaker_components/pdf/FE126En.pdf

They are 105L Tuned to 60Hz according to the Fostex Plans.

I know that they will not sound as good as a horn according to the various forums, but what I want to do is learn along the way, get used to the BR and then look at building a suitable Horn once I know more.

What's so bad about the Fostex Hybrid box plan compared to the other designs?

To make this starting project sound the best I can what do you recommend? Please don't say don't bother and start with a Horn strait away. I could do that but the journey of learning is important to me.
I have been listening via commercial Hi-Fi for over 20 years now and feel that the internet forums are giving many of us freedom from the commercialism, snake oil and spin.

I am in the process of building a Lenco GL75 TT with heavy plinth and Rega RB300. This has taken me a couple of years to do due to work and family commitments but I am almost there.

I also have a Thorens TD160 and Yamaha YP900 TT for vinyl duties.

I have built a Vortexbox player loaded up with FLAC files from all my CDs as well as having various CD players and Dacs I can use.

I have a 20w SMSDL class D amp, a 40w Push Pull EL34 amp and various SS amps to choose from as well.

At present I am listening to Mission 752 floorstanding speakers and Proac S1C stand mount speakers. I prefer the proacs but they cost 3x as much.

I listen to MOR, contemp country, some classical and film soundtracks, (I love the mellow stuff from Hans Zimmer like the Last Samurai) and love women's vocal and things like Diana Krall.

I don't listen to very loud music, probably about the 10 0'clock position on the amp volume.

Back to these speakers, I have bought the drivers from Wilmslow audio along with Monacor MDM-3 lambswool stuffing for the speakers.

I am looking to use some high quality silver plated OFC cables that I have in the box.

The listening position is approx 9ft away and my current speakers are 5ft apart although they could be 9ft apart

Can you please help me with some of these questions before I start to assemble:

As its a BR Box do I need to us a resister for the FE126En to tame it?

How much stuffing / damping of the BR box is required?

What mods should I make to the speakers?
(I cannot find 'Duct Seal' on Ebay or in any hardware shops in England)

Is there a gasket that needs fitting between the speaker and the box?

Any advice on using Cones or Bluetack on the Partington Dreadnought speaker stands?

Any tips on getting the speakers just right before committing and screwing them into the box.

I will run them in for a 100hrs before any listening, using a burn in CD on FLAC. Should I do that for a constant 100 hrs or limit the times to burn them in?

The next project later this year once my Lenco is finished will be to build a horn enclosure.

Any early advice to start thinking, dreaming, researching about would be good. I don't think I would be able to get away with a kongo or other similar tall horn due to WAF but you never know so may be looking more at the more compact horn enclosure.

I know much depends on the room and WAF

Thanks

Lee

 

[Scottmoose]

Ye gods, that's a battery of questions. I don't think many people have the time to answer quite that amount from a single post. I'll do my best since I've a few minutes over my lunch hour.

I know that they will not sound as good as a horn according to the various forums, but what I want to do is learn along the way, get used to the BR and then look at building a suitable Horn once I know more.

They'll sound different.

What's so bad about the Fostex Hybrid box plan compared to the other designs?

It's rubbish. Resonances all over the shop, poor gain, severe midrange colouration. Would you like me to continue?

As its a BR Box do I need to us a resister for the FE126EN to tame it?

Do you mean a shelving filter? Yes.

How much stuffing / damping of the BR box is required?

How long is a piece of string? Line the faces initially & add more later if required.

What mods should I make to the speakers?
(I cannot find 'Duct Seal' on Ebay or in any hardware shops in England)

You're not obliged to make any, but if you look over some of the material on the Planet10-hifi site, you'll get some ideas you could try.

Is there a gasket that needs fitting between the speaker and the box?

The drivers come with one.

Any advice on using Cones or Bluetack on the Partington Dreadnought speaker stands?

Try both and see what you prefer. Only you know what you like.

Any tips on getting the speakers just right before committing and screwing them into the box.

Don't use screws. Use something that's more easily detachable that doesn't tear the wood apart. Otherwise, since you haven't built them yourself, there's relatively little you can do with the cabinets.

I will run them in for a 100hrs before any listening, using a burn in CD on FLAC. Should I do that for a constant 100 hrs or limit the times to burn them in?

Depends who you ask and exactly what material you're using. The way the 126 is designed, I'd just leave them running.

 

[xrk971]

That is some beautiful veneer. Also, the bellmouth vents made of wood look really nice. I can't believe you have not stuffed the drivers in for a listen yet! I have heard some very nice things about the FE126 in a Frugelhorn Mk3 (FH3) - lots of threads on it - do a search and you will find it. But if you want to try this driver in a nice horn, that would be a good place to start.

 

[eldarvanyar]

Thanks Scott for taking the time out of your lunch hour to answer. Its my day off today probably why I got a bit carried away with the questions.

What's a shelving filter? Is it a resistor in parallel and what value type do I need and where and how do I fit it? I presume I solder it?

If I don't use self tapping screws can you put in the right direction what to use and where I can get them from?

I bought the self tapping socket hex head screws below

Fixings

This is all new to me so I really appreciate the advice

Thanks again!

Lee

 

[eldarvanyar]

Hi XRK971,

I have been tempted to try them out but I am looking forward to assembling them with all the parts in one go due to lack of time.

One day I will build a horn later this year once I have some hours under my belt with this.

I do like the cabinets, I have put beeswax on them and been polishing like mad, which is after the picture was taken. I will post once its all in situ.

Thanks

 

[xrk971]

Hi XRK971,

I have been tempted to try them out but I am looking forward to assembling them with all the parts in one go due to lack of time.

One day I will build a horn later this year once I have some hours under my belt with this.

I do like the cabinets, I have put beeswax on them and been polishing like mad, which is after the picture was taken. I will post once its all in situ.

Thanks

Eldarvanyar,
I liked the shape of the FH3 so much I was inspired to build a small homage to it out of foam core. It actually sounds quite nice and is one of my favorites. Here is what I ended up with using a TC9FD driver. http://www.diyaudio.com/forums/full-range/227460-fh3-inspired-foam-core-mini-build.html

I hear that the FH3 flatpacks are a relatively painless build - takes a lot of clamps more than anything.

 

[eldarvanyar]

Hi have looked on here

Loudspeaker Diffraction Loss and Baffle Step Compensation Circuits


Where:
Re is the DC resistance of the driver voice coil [ohms],
Wb is the width of the baffle [inches],
dB is the amount of attenuation required [decibels],
f3 is the frequency midpoint of the transition from 4π space to 2π space,
Lbsc is the calculated baffle step correction circuit Inductor [mH] and
Rbsc is the calculated baffle step correction circuit Resistor [ohms].

Put in the info on the calculator

Re 8 [ohms]
Wb 7.08 [inches]
dB 93[decibels]

This is what it gives me

f3 644.1 [Hz]
Lbsc 88301.7 [mH]
Rbsc 357338.9[ohms]

Really sorry to be thick and hopeless, what do I now need to buy?

Thanks

Lee

 

[Scottmoose]

Re is the actual value (7.2), not the nominal impedance (which means nothing). The amount of attenuation you enter is the number of dB you need to lose from the output. In this case, I'd aim for the full 6dB since you're not just needing to compensate for step loss but the inherently rising response of the 126 drive unit. The tradeoff for obtaining a balanced response is that total sensitivity drops.

More realistic values are 1.8mH paralleled with 7ohms in the hot lead.

 

[eldarvanyar]

Eldarvanyar,
I liked the shape of the FH3 so much I was inspired to build a small homage to it out of foam core. It actually sounds quite nice and is one of my favorites. Here is what I ended up with using a TC9FD driver. http://www.diyaudio.com/forums/full-range/227460-fh3-inspired-foam-core-mini-build.html

I hear that the FH3 flatpacks are a relatively painless build - takes a lot of clamps more than anything.

Awsome how do they sound?

I have looked online for the FH3 kits i think the postage makes them prohibitive as I can't find them in the UK only in the USA

 

[xrk971]

My little foam creations sound great - I love them! The imaging is fantastic, the vocals are my favorite aspect, and the bass extends down to about 60 Hz and is sufficient so that BSC is not required. I have not heard what a real FH3 sounds like but can only imagine it is much better if using a larger and higher quality driver in a wood cabinet. I believe there are FH3 flatpacks available in the UK. Planet10 or Scottmoose can point you to sources.

 

[chrisb]

1) you mean 10.5 liters
2) this design will arguably sound less horrid than the atrocious hybrid enclosure (which I built several years back) , but I'd take the "tuned to 60Hz" with a small dash of pink Himalayan salt - without severe EQ, and corresponding reduction in usable SPL \ excursion, don't expect much torque below 100Hz in this enclosure
That's easily enough cured with the use of compact supporting woofers
3) nice work on the veneering

 

[planet10]

.... FH3 kits i think the postage makes them prohibitive as I can't find them in the UK...

You can't actually find them in the USA.

Colin (aka Toppsy) makes FH3 flatpaks. He is just NE of Manchester.

The Macassar Ebony is lovely.... and expensive. We did a pair of uFonken clad in it.

What i do hope is that this project does not turn you off full range, as this particular box design conspires to exagerate what the FE126En does not do all that well. Warning: after spending all that money on those boxes what follows may be painful ... but there is an out.

From the sims you can see that with this box any bass response you have will be way down which will exaggerate the FE126's forward midrange and the 7k peak.

The top curve is half-space (ie what you would get if you mounted them flush in a wall or approximately what you would get with BSC added). The lower curve is with no filters and a simulated 6 dB of baffle loss. You would need a 2-stage filter to give any semblance of flat response. You would lose some 12 dB of sensitivity and then you run into the very low xMax which means that for anything but nearfield use you are likely exceeding it, and even there you probably won't be able to really push them. Further, in our experience, this kind of filter reduces the speakers DDR (downward dynamic range) and wipes out some of those things that makes the FE126 special.

All of these things work together to make this enclosure what another member described as a cruel joke.

Not all is lost thou. The FF125wk will drop right in and give much more satisfactory results (top curve). The box is still a bit big, and perhaps could be tuned a bit higher, but they could be done after the fact. Just add up to 2 litres of solid fill. Make it irregular, stick it to the backs, sides, level with the driver to break up standing waves, and on the bottom/top.

dave

 

[planet10]

You can't actually find them in the USA.

After a panicky email, let me expand on that. FH3 flatpaks for the USA are currently made in & shipped from Canada.

dave

 

[JR_W]

I didn't mean to come off as panicky or hijack the guy's thread, but as I'm in the USA I was just hoping that I'd still be able to "find" the pair I ordered. It sort of sounded like there were no more to be found here. Glad to find that I was mistaken.

 

[planet10]

 

[Bob Brines]

Ok here's my speaker in Madagascar ebony. Fostex F200a/FT7RP and high gloss finish.

Bob

 

[eldarvanyar]

Hi Dave,

Thanks for your very comprehensive and helpful reply. It did make my heart sink a bit but I thought, well I might as well put them in and see what they sound like. It will be an education that's for sure.

I am burning in the speakers for a 100hrs using an XLO Reference Burn IN CD MP3 and some Hams Zimmer Movie Albums on an old mobile via the smsl D class amp. They have been on for 48 Hrs now and the phone and amp are not even warm.

I did check with Colin about Frugal Horn Kits and he is not doing them any more for the foreseeable future. Do you have the CAD files for them as I may be able to get them made up by a company with a CAD machine?

I think the whole thing of a adding a filter will defeat the point of them losing 12db and is probably too complicated for me.

What would you recommend if I were to use a subwoofer for now?

I think when I build a proper horn enclosure then I will put some FF125wk speakers in as you suggest.

What would you say would be the difference between a FH3, Kongo, BK12m cab?

 

[chrisb]

Hi Dave,

Thanks for your very comprehensive and helpful reply. It did make my heart sink a bit but I thought, well I might as well put them in and see what they sound like. It will be an education that's for sure.

I am burning in the speakers for a 100hrs using an XLO Reference Burn IN CD MP3 and some Hams Zimmer Movie Albums on an old mobile via the smsl D class amp. They have been on for 48 Hrs now and the phone and amp are not even warm.

What would you say would be the difference between a FH3, Kongo, BK12m cab?

I'm quite familiar with the FH3 and BK12m, and have heard the earlier Saburo, but not Kongo; my assessment of the differences would be - they don't sound the same (duh..) , but the more salient question would be - " which might be the most suitable compromise for you?" In the case of these 3 designs, that depends very much on your room and placement issues.

The BK12 is the most compact of the bunch, and suitable for small rooms- the Kongo being a tall double mouth design definitely delivers more LF gain and larger soundstage than the BK12, but also requires a greater primary listening distance for integration of the 3 sources.

To take full advantage of its rear mouth design, and particularly the corner/boundary loading that delivers the optimal performance with the FE126E, the FH3 has the largest effective foot-print requirement of the 3. Personally it's my favorite of the bunch - but as much as I hate to use the term, the "best" enclosure I've heard for this driver is the Woden Valiant - approx the same size as Kongo, but like the FH3, a rear mouth design.

 

[chris661]

I think the whole thing of a adding a filter will defeat the point of them losing 12db and is probably too complicated for me.

What would you recommend if I were to use a subwoofer for now?

A couple of things...

I found FE126s really need a good thrashing to come on song. Seriously.

I used 15 Step by Radiohead, wired the speakers out-of-phase, and left them face-to-face playing with ~3-4mm p/p excursion. Cover with a duvet to avoid annoying people. Give them as much time as you can, then listen again.

I found the sound really changed each time for the first 20 or so hours of really giving them some pain. Apply bass boost (via phone, iTunes, whatever - just make the cones move).

Once you've broken them in...

Plug a computer into the amplifier, and use Foobar2000 or even iTunes.
Using the equaliser, apply the curve shown below.
The overall HF shelf is -3dB, for baffle-step compensation.
Then overlaid there's a broad notch filter around 7kHz. These drivers have a lot of output around the upper midrange, and this should knock them down into line. Should sound more "relaxed".

Put something reasonably neutral on (try Sultans of Swing, for example), and listen right through the track. That should give your ears a little time to adjust to what you're hearing.
Now play anything you like.
Tweak the eq if you want a more forward/detailed sound by reducing the cut around 7kHz.
If it sounds too warm and lacking in definition, move all the attenuated sliders up by a decibel.

Make incremental changes. What I've shown will be somewhere near, but your tastes will be different to mine.

Chris

PS - spread them out a bit! You'll get no stereo image with them so close together.

PPS - if you want to go the subwoofer route, I'd advise stereo woofers, cross ~500Hz. For <80Hz, do it well or don't bother. A little box booming away in the corner constantly attracting attention isn't HiFi.

 

[chris661]

Bumping this again, as I've just tried something that may be of interest.

My FE126s are in ~1.5L sealed cabinets, and usually have a 6.5" woofer doing <500Hz for them.

I disconnected the active crossover, so it was computer > passive preamp > amplifier > Fostex.
Initially, it sounded pretty bad. No bass what-so-ever. The rolloff starts around 200Hz, IIRC.

So I threw together a really quick Linkwitz Transform (using the positively astounding iTunes eq), which brought the bass back in line.

At a couple of metres listening distance, there's still considerable volume available. Not as loud as it was before, for a couple of reasons:
1 - I've run out of gain before the soundcard clips
2 - I can see the surround of one of the drivers deforming slightly when any low end comes along, so won't push it much further.

Still sounds rather good, though. Its also a sound that I'd call full-range: nothing's really missing.

If you block the port with something reasonably solid and check the cabinet volume in WinISD for an idea of where the rolloff is, you could do something similar very easily.


If I ever change speakers, I'm gonna make these into my computer speakers, and build an amplifier + LT into the cabinet. Much, much better than I expected.

Chris