diyAudio (
-   Full Range (
-   -   Sealed Fostex FE126/7 (

a1rocketpilot 17th October 2005 08:11 AM

Sealed Fostex FE126/7
First time poster here. I am planning to make a dual driver setup using the Fostex FE126/7, similar in design to the Omega Speaker Systems TS 33. However, I want to make a sealed enclosure, since I'd rather have tight and accurate bass than extend down a few Hz more.

I have several questions though.
1: Should I use the 126 or the 127?
2: Should the drivers be wired in series or parallel?
3: Where can I find useful information on how to actually design an enclosure? Everywhere I've looked, they've just given descriptions of the different types as opposed to actually telling you how to optimize one.
4: As a final question, would I end up happier in the long run with a system like this or by waiting and saving up to upgrade to the Hammer Dynamics Super 12's (my much more costly alternative)?

Any advice on these questions would be much appreciated. Thanks a lot!

bobhayes 17th October 2005 12:21 PM

The FE166E has a low Q (highly damped) and will be very bass shy in a sealed enclosure.
The FE167E would be better in a sealed enclosure, but is still has low Q.
Experimenting with volume might give you a reasonable bass level (smaller box raises bass level but cutoff is higher).
Why not build a double BR enclosure like the fostex recommended ones?

Roemhild 17th October 2005 01:35 PM

2 Attachment(s)

On the picture of the OMEGA's are Fe127e.

I've used Fe127 and Fe127e.

Personally I like the Fe127 better because I've the feeling that the resulution (?) of higher frequency is better.

Both are playing in a combination with two 13cm drivers. I wouldn't use two drivers per side.

The enclosure for the FE127 is something arround 0.8-1.1 liters.
The enclosure for the Fe127e is something arround 3.5-4.5 liters.

I wouldn't run these small Drivers under 200Hz so you will need a Bass/Subwoofer under the Fostex.
left is the Fe127e / right the Fe127

x. onasis 17th October 2005 04:16 PM

Welcome A1. You should have a look at this thread ....that should answer questions 1,2 and 3. I built a few of those designs and the Bi-pole TL is by far the best design.

Getting useful bass out of these drivers is the point of using something other than a sealed enclosure.

To answer question 4 is more difficult, but even you won't know the answer unless you build both. Prolly depends on how interested you are in building in the first place, and why. Feel free to elaborate on your're among addicts here.

On a related note: I have a pair of 127E's left over from those projects and Roemhild's post gets me thinking about using them in a 2-way or similar. Anyone have more thoughts on that?

SCD 17th October 2005 07:04 PM

I made a set of folded MLTL from the noted thread. (post 446 of noted thread) They sound great and look pretty good too. This is a great driver. For my ears it does not need a tweeter, it could use a sub to help augment the lower octaves but it really shines in the mid range. I highly recommend the designs noted in the thread referenced by x. onasis

It is a long thread but worth the read if you are interested in FE127 designs.

Good luck
I hope this helps

Josephjcole 17th October 2005 09:12 PM

One thing to consider that has not been mentioned yet is that bass reflex helps to control cone motion at the tuning frequency. These are fairly small drivers that if run open will run out of excursion at higher volumes, the port loading can do some good in this respect. Of course the driver will unload at frequencies below the port tuning. It's all give and take but I would certainly take an MLTL design over a sealed for this driver if you want to run it open. Of course you could have a subwoofer then it would be a whole different deal.... my prefred option would be to seal them and role them off around 300Hz to a large Pro Sound woofer.

just my :2c:

landpirate 18th October 2005 03:47 AM

Roemhild Hi Nice speakers in the thumb nail. Are the 27 & 27e the ones in the middle and what are the other four if you don't mind me asking.:skull: :Pirate:

Roemhild 18th October 2005 06:52 AM

Hi landpirate,

the driver in the middle are the Fostex Fe127(e). The other ones are from Monacor


They are playing in a bass reflex. The only difference between these two speakers is that the round version has the Fe127e and of course the design shape. If you are interessted I can post the plan for the straight version and the x-over.

bst regards Till

Floric 18th October 2005 07:02 PM

Hi Till,

I would be very interested in your plans and crossover for the Fostex d'Appolito because I am thinking of a Fe127e with bass support. My ones are running in a bass reflex enclosure at the moment and I am not very content with the bass though it is really amazing regarding the little speakers in those little cabinets.

Did you think of building a horn "your kind" for the fe172e?



Roemhild 18th October 2005 09:21 PM

2 Attachment(s)
Hi Flo,

first to the question about the horn: No I have never thought about a horn for the Fe127/127e because I wouldn't get deeper than the fs.
That's the reason why Raffi and I have build the horn for the Vifa.

I will try to finish the plans tomorrow for the preso.
The x-over of the preso is very easy and can give you a good start for your own x-over design. A few years agow I have tried symetric x-overes with a very good result. Just try it out:

cap: 2x 68F
coil: 2x 1.8 mH

I had to reduce the Fe127e about 2dB so I took resistors with a value of:
2x 1 OHM
1x 33 OHM

I had to change the values of the caps a bit so take this x-over just for a starting point.

All times are GMT. The time now is 05:04 AM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2