Fostex FE103A small footprint cabinet options

I've come across a pair of (apparently) unique FE103A and given the dedicated cabinet Fostex released for them is no longer available, is anyone aware of a suitable enclosure that can accommodate the very deep drivers?

Screenshot_2023-09-19-16-49-00-16_1883c7f851f01ba16e32f0f357d2f56b.jpg


Due to room size floor standers and horns are out of the question. The Solo-103 design for FE103 won't work with the FE103A due to clearance problems.

Screenshot_2023-09-19-16-34-11-31_57e717c094f371a1dada6567a1123b99~3.jpg


Fostex do have a simple bass reflex cabinet which might work:

https://www.fostex.jp/products/bk105wb/

However I think a cabinet like this would be doing a disservice to an Alnico driver such as the FE103A.
 
frugal-phile™
Joined 2001
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I have gone thru a whole lot of FE103A, none teh collectors edition you have scored.

I worked from measured data which i have always found a bit off for reflexes.

They perfomed best in Aiko.

Do you have T/S provided by Fostex?

BTW: FE103A is my term for the driver class. Does Fostex actually use that name?

dave
 
Thanks @planet10

Yes I noticed from the threads that you had referenced the 103A class independently of Fostex.

Fostex released this limited edition 70th Anniversary driver a few years ago and indeed named it the 103A.

As far as I can tell there are not many left in circulation. It's a beast of a driver for a 4 inch unit!

I've attached the datasheet here.

Fostex did release a specific cabinet for this driver but it's no longer available - info also attached but I think the Aiko or Minionken would be better, just a matter of getting a design which can actually house the driver.
 

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  • FE103A_specs.pdf
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  • Fostex_YK103A_manual.pdf
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frugal-phile™
Joined 2001
Paid Member
The results are not promising. High Qs. large Vas (for the driver size).

A small box will not be that small. Not sure how small it can be squeezed into.

At the moment i have a decent looking alignment for a miniOnken (won’t do all that well in a regular reflex, sealed probably won’t do it either).

The Xmax will be exceeded in the LF at less than 1W but Fostex Xmech is far larger. 15 litres.

I can see if it can be squeezed further if you’d like.

The Fostex enclosure is probably too small.

A TL of some sort, or a horn specifically for, or Frugel-Horn Mk3 would likely be optimum.

dave
 
Excellent I'll see if there is a local supplier with CNC machinery and try to bring another pair of Fonkens to life!

Out of curiosity, does anyone know what sort of design this cabinet is based on?

I came across it in the search for something that would fit. It's less than 5 liters so probably not suitable but I'm not sure what the idea behind the physics is here?

Screenshot_2023-09-20-09-19-46-71_40deb401b9ffe8e1df2f1cc5ba480b12.jpg
 
Earl, Dave’s Fonken style enclosure as displayed in the YT video has proven to work very well - a lot of bracing in the design, and well controlled LF roll off - at the expense of “gut punching, dynamic impact” - but as he notes, the absolute best I’ve heard the 103 sound was in Scott Lindgren’s Aiko.
 
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Earl, Dave’s Fonken style enclosure as displayed in the YT video has proven to work very well - a lot of bracing in the design, and well controlled LF roll off - at the expense of “gut punching, dynamic impact” - but as he notes, the absolute best I’ve heard the 103 sound was in Scott Lindgren’s Aiko.

The Aiko design file isn't loading on the p10hifi site, does anyone have the PDF of the drawings? Size is certainly a concern but it's worth considering all options.....