Fostex Fe166En build

har297

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Hi All..

After listening to a Full-range setup assisted by a Subwoofer, I was bitten by the magic of vocal reproduction by full-rangers, also this was a easier step in achieving better sound quality mainly because hassles of crossover design and tweaking is skipped. And any coloration it "may provide", i would skip about this as i am no expert in crossover design.

To realize this, best budget to performance ratio was found to be in Fostex drivers, with lot of documentation and measurements available across forums, as a next step, few drivers were shortlisted fe126en, fe166en & fe206en. All of these have been proven to provide excellent results if implemented right.

Then began finalizing the driver, as this may sound simple, but it took lot of going back and forth between these three.

Finally, after several months, as impulse order fe166en was bought, main reasons to choose 166 were relatively flat response compared to 206. Can try to avoid BSC as the main intention of trying a Full-range was to have no passive components between amp and driver. Even though 126 was a highly regarded driver, 166 proved to be a bit more robust in low end of the spectrum, this if we want to listen without any kind of bass assist, it can be manageable.

So now comes the tricky part of the build, choosing the enclosure.
I had a chance to listen to the BLH enclosure recommended by Fostex, this sounded really good, but i am not sure if there are any better designs (BK-16, Jericho, Metronome, etc).

So want to know if there are any recommendations for the enclosures.

Thanks
Har297
 
Here are the specs

Impedance - 8 ohms
SPL - 94dB/W(m)
Rated input - 22W
Sd - 0.0133m2
Zn - 8 ohms
Fs - 53 Hz
Re - 7.2 Ohms
Le - 0.052mH
Qms - 3.426
Qes - 0.266
Qts - 0.25
Mms - 6.8 g
BL - 7.65 Tesla/m
Xmax - 1 mm
Cms - 1.474 m/N
EBP - 199.25
 
I had build the Metronome with the FE166en driver last year. I later removed the whizzer cone due to extreme harshness in the mid and upper mid range region accompanied by the classic full range driver shout.

I later discovered that you should not do any tweaks to the driver unless its burnt for a minimum of 100hrs (more the better). Only after that you should try to balance the lows, mids and the highs. For me it was over-enthusiasm to get it right soon and hence later i now mate the fostex with a ribbon-tweeter to take over after 5.5KHz. The good thing was, the trick worked for the better.

Now i am not very sure about the low-end if i would be requiring a sub-woofer or not. The fostex does give me a good low-end, with deep and tight bass but at times i get a feeling that a gain one-octave lower would have been beneficial. The major crux with the subwoofer was to find the right amount of space in my small listening room and to tame the possible boom that would accompany.

You will need to discover various solutions on the way to find the best approach and solution to live with the fostex. No one approach or no approach would be the best. My 2 paise.
 
Thanks Hari,

Your Metronome build also was a deciding factor towards fe166.

I am not sure if i will try modifying the driver :) not adventurous enough :lol: if i feel there is a need for high freq detail, i may go towards FT17H starting at a higher point, as they sound good along with 166.

And true about the Subwoofer integration, but as you said the lower octave may be missed a bit (being a bit of bass freak) , but finding a good Sub with the same attack as fostex may be a bit of challenge , more to be read on this area.

Thanks
Har297


I had build the Metronome with the FE166en driver last year. I later removed the whizzer cone due to extreme harshness in the mid and upper mid range region accompanied by the classic full range driver shout.

I later discovered that you should not do any tweaks to the driver unless its burnt for a minimum of 100hrs (more the better). Only after that you should try to balance the lows, mids and the highs. For me it was over-enthusiasm to get it right soon and hence later i now mate the fostex with a ribbon-tweeter to take over after 5.5KHz. The good thing was, the trick worked for the better.

Now i am not very sure about the low-end if i would be requiring a sub-woofer or not. The fostex does give me a good low-end, with deep and tight bass but at times i get a feeling that a gain one-octave lower would have been beneficial. The major crux with the subwoofer was to find the right amount of space in my small listening room and to tame the possible boom that would accompany.

You will need to discover various solutions on the way to find the best approach and solution to live with the fostex. No one approach or no approach would be the best. My 2 paise.
 
Similar to the above discussion, can anyone suggest me the best enclosure for Mark Audio 12P full rangers?
Thanks in advance.
 
The Qts is good for TL, but Hari, would Xmax of 1mm be enough for some reasonable bass output in a TL ?

What about BLH ?

Open Baffle is out of question.

I have seen some interesting designs which were kind of hybrid BLH - TL .

I am using the Fostex in a hybrid TL. meaning for frequency below the tuning frequency which is 59Hz it behaves like a TL and above this frequency it behaves like a horn speaker. With my current speaker placement and stuffing of the enclosure the bass is very much adequate and i did not find any issues. I can easily listen till 35Hz (-6dB) without effort.

The 1mm xmax is better for a better and clear mid-range response. Too much of xmax in the dirver will cause the mid-range to smear and introduce coloration. Hence when building with this driver its very important to take care of box tuning and stuffing appropriately. I suggest to tune slightly above resonance of the driver (53Hz) so that cone motion is to the bare minimum. Below the resonance the output is dictated by the terminus and above resonance by the driver. Freeing the cone motion at around 60Hz will give you good mid-range transient without causing much cone vibration.

BLH is a good option if you have enough space for the box in your listening area. In my case space was a constraint and hence settled for a meterononme.

OB can be good with this driver, but the bottom end will require support from an subwoofer. I do not have experience with this setup though.
 
I have listened to the FE166en built by FM Satyaki some 4 years ago and was thrilled by its SQ. Infact, i wanted to built with the Fostex after that session. But these speakers requires a larger floor and ceiling area and was not practical for Mumbai type small rooms.

Infact the BLH design comes along when you purchase the FE166en. If you have the space and the skills to built the BLH, you should try this option first as its the recommended enclosure for the driver. If floor space is a constraint then the Metronome will be a good option too imo.
 
Here are my Jericho Horns built last month with my Fostex 208 Sigma drivers. Those Frugal Horns look so puny beside them ;)
Time to dispose off my Frugal Horns as no space in the living room.

qyw9aa.jpg
 
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Here are my Jericho Horns built last month with my Fostex 208 Sigma drivers. Those Frugal Horns look so puny beside them ;)
Time to dispose off my Frugal Horns as no space in the living room.

Wonderful, manniraj. I'm sure they produce beautiful sound.
 
Wonderful, manniraj. I'm sure they produce beautiful sound.

Thanks Rajiv, oh yes they are lovely and mesmerizing to hear, punchy bass and awesome mid range with vocals. Need to hear them with a tube amp (may be any local member can lend me). Also have to plan for the finishing this build with either veneering or painting.
 
Good to hear this Manniraj, If you offer an audition then perhaps I or others can lug our tube amps :) Cheers
 
I had grand plans many moons ago for a Fostex build (although my drivers were different but similar in size). But my dreams remained exactly that and I sold my drivers. What i recall from my research was that I was leaning towards building a Fonken. Generally, horns are considered the best design for this Fostex driver but the Fonkens have quite good reviews as well, and can be built as slim floorstanders or as bookshelves. And Dave from Planet10-hifi is extremely friendly and helpful. He will also design a cabinet for your specific driver if he doesn't have it already. They also sell flatpacks but from what I remember, the cabinet designs are freely available for personal builds.

It looks like they also have their designs at the frugal-phile site. There's already a design for the Fostex 167.
 
Thanks Rajiv, oh yes they are lovely and mesmerizing to hear, punchy bass and awesome mid range with vocals. Need to hear them with a tube amp (may be any local member can lend me). Also have to plan for the finishing this build with either veneering or painting.

If you want tube amp for demo, i can get mine .

Your Jericho horns look huge..

Thanks
 
If you want tube amp for demo, i can get mine .

Your Jericho horns look huge..

Thanks

Sure we can plan for a visit and yes they are huge and very very heavy. I could not alone move them to the spot they are currently installed, had to take help. What tube amps do you have as I read that single ended amps gel with this design and driver well.
 
I have a EL34 based SET (running at very low wattage of around 3.5W)

Sure we can plan for a visit and yes they are huge and very very heavy. I could not alone move them to the spot they are currently installed, had to take help. What tube amps do you have as I read that single ended amps gel with this design and driver well.
 
Simlated a BiB for this driver, and got a respectful size (considering it is a BiB ;) )

There are good reviews for this design especially in the LF region.

Width (external) 11.000
Depth (external) 15.000
Height (external) 64.5

*dimensions in inches


Thanks
Har297
 
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