What cabinet to build for a Fostex FE168 S Sigma?

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andyjevans

andyjevans

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artsandmedia.com
#1
I just won a pair of Fostex FE168 S Sigma on ebay. What sort of cabinet should I build?

Don't want to build a large and complex horn but should be fine building something a bit simpler and less large. I've built speakers before and have tools and skills. My listening room's not that big, so tall is OK but trying to avoid a large front-to-back footprint.

All suggestions extremely welcome - I'm waiting to get started!

Andy
 
#3
andyjevans said:
I just won a pair of Fostex FE168 S Sigma on ebay. What sort of cabinet should I build?

Don't want to build a large and complex horn but should be fine building something a bit simpler and less large. I've built speakers before and have tools and skills. My listening room's not that big, so tall is OK but trying to avoid a large front-to-back footprint.

All suggestions extremely welcome - I'm waiting to get started!

Andy
Click to expand...

Looks like Scott beat me to it, but the first that come to mind would be BIB or Metronome - certainly among the simpler builds around , and probably smallest footprint,



The Metronome

An externally hosted image should be here but it was not working when we last tested it.




or Scott Lindgren's own Hiro

An externally hosted image should be here but it was not working when we last tested it.



http://homepage.mac.com/tlinespeakers/FH/download/Sachiko-map-1v01-220309.pdf


There are also a couple of the larger Fostex BLH (Nagaoka) manifold horn designs for 166 etc that have been well reviewed - however, they are a time consuming build, and consume even more material than Hiro.



Of course the simplest enclosure is none- there is always something like the MJK Open Baffle concept - with support by a 15" woofer. Someone must have tried that by now.
 
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#6
andyjevans said:
Hi guys,

Thanks for your quick responses! Where can I find the plans and dimensions for the Metronome and an appropriate BiB?

Many thanks,

andy
Click to expand...


If you're not already familiar with the designs, take a quick trip through the sites for a background.

There are tables of calculated dimensions for a wide range of drivers for each of the design types, and in some cases detailed drawings or photos.

BIB:


Bigger Is Better 'BIB' Cabinet Dimensions - ZillaSpeak


Metronome:

The Metronome
 
#9
Hi andyjevans, congrats (I saw that auction).

If you go BiB, use the BiB calculator on the BiB site. It will tell you the exact dimensions for every piece, allow you to choose material thickness etc. It will also calc a tad differently.

Hiro looks very tempting, as does Bob's MLTL. Why not build them all 🙂
 
#11
Andy, are these the old Σigmas with the whiz? I have a pretty good box for these. It's a it's a PITA to build, but sounds very good.

The Untold Story

speakFinal04.jpg


Aloha,

Poinz
 
#12
Poinz - inspiring, as usual. It seems to me that this wouldn't be too hard to build IF I had access to some kind of bendy material. You've used wood, which as you say is a PITA. But there must be some kind of material that is bendy yet robust and about 1/2" thick? The curves would be glued on each side so should be stable. Anybody come across a material like that? Can't be rocket science.

Andy
 
#14
Kerfkore seems to be a US product and I'm in UK. I did look at some bendable MDF in a store, but is didn't seem to bend to the radius needed for such speakers. there's this:
MDF - Bendy

On this site they say radius is 150mm - that seems optimistic to me unless I was looking at different stuff in the store.
Bendy MDF

I was wondering about some sort of heavy rubber material. Like this stuff is made in 10mm thickness.
Commercial Rubber Sheet - Rayflex Rubber

Not sure how practical all these DIY ideas are for back loaded horns.

Andy
 
#15
andyjevans said:
Poinz - inspiring, as usual. It seems to me that this wouldn't be too hard to build IF I had access to some kind of bendy material. You've used wood, which as you say is a PITA. But there must be some kind of material that is bendy yet robust and about 1/2" thick? The curves would be glued on each side so should be stable. Anybody come across a material like that? Can't be rocket science.

Andy
Click to expand...
Use several thin layers.
 
#16
You guyz, if you click on the link there, there's a methodology to do the thing with common plywood (or even lumber), y'know.

Wun mo' time!

There's such a thing as 'benderboard' as well, but it's not cheap, and you got to lam up six layers of it (it's 1/8" stuff), and so on. I looked at a lot of ways of doing this, and decided that making it a kerf bending tutorial for m'seff was The Way.

'Course, y'all gotta go where y'all gotta go.

P
 
#17
Hello again. I've applied myself to calculations of the BIB. My provisional plan is as follows for a quick build. Use Contiboard - that cheap laminated board available everywhere, and cheapest in white. Use 9" for the front and back (and partition) and use a double thickness on the front. Use 12" for the sides. Use a total line length of 132" so height is 66". This gives the following calculations.

How does this look?

Fs 60
Vas 0.54
Qts 0.37
Line Length 132.0
Folded Height 66.0
Vb 3.5
Sm 92.0
Depth 10.22
Width 9.0
zdriver 28.6
a-b-c 5.1

Comments welcome!

Andy
 
#18
Hello again!

I haven't started building yet so still in the choice stage. Going over my possibilities for the FE168S I also see two bass reflex designs. One is 53 litres and the other is the one on Godzilla's site which he seemed happy with - the Japanese design which is reported as 48 litres.
Single Driver Website

I don't know if I'm reading the original Japanese drawings right but these look like 65 litres
http://www2.nkansai.ne.jp/hotel/nakanou/**-168.htm

I'm trying to choose between a BIB and these ported box designs. Can anybody help me here with some useful input about how these sound and what would be a preference?

Andy
 
#20
Hi Andy!

>>> Depth 10.22

I had to triple! up the front of my BIBs to make sure the magnet on the back of the 168s did not touch the inner baffle. Please check your measurements! Also, the large ported box is very good sounding too... but it does have a bit of a one note bass sound on some music... while sounding rich and effortless on most music i listen to. I do really like the easy presentation of the large ported box personally. The BIB needs corners to sound it's best filling out the bass. I will have to look for the old Japanese file i have somewhere from the designer of this driver... he recommended the large ported box. I believe it's a double thick walled 48L not 65L... the large ported box i built was single walled plus a bit of light bracing on the front so this may be why my box doesn't sound optimal. Also, Scottmoose simmed years ago for me how the 168s would work in the straight pipe i built (which is slightly wider than it should have been) and the sims are pretty nice. I will try to gather it all and post later. Fact is, this is one of the best full range drivers imo. They can be used in lots of different boxes from small ported to large ported to back horns... pipes, BIBs etc... i also built two other smaller ported boxes and liked the 25L but not the smaller one. When you go too small the bass really thins out with this one.

Godzilla
 
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