Fostex Fe167e as center in HT - sealed?

Crossblade

Member
2006-07-06 9:32 pm
Hey guys,

I am expecting to receive a Fe167e to use as a center speaker in my Home Theater surround system (Thanks Dave!). Phantom center is good, but only when you are in the sweet spot (1 person).

As I will have to put it below TV height, the driver must be pretty low (less than 80cm/31.5" for its upper end). That rules out every available cabinet (Chili, Fonken, bib, MLTLs) but the bookshelfs.

I was thinking about the recommended 15l bass reflex enclosure, but sized in a way that it is wide and short - a "Horizontal speaker". But as I do not love BR, and do not expect miracles in the bass (though I do NOT want it to sound thin), can I do a sealed enclosure?
It can be big, as I will put it BEHIND my audio rack - it can be wide, tall (but the driver at low height) but rather thin as I do not have much space behind the rack. Or it can be normally sized (like < 30l).

About the location: Yes, I realize this way there will be some reflective surface in front of the driver, but I will try to keep them at minimum and that is the only way I can put a center speaker. I cannot put it above the TV.
Here is a sketch of my room, but my rack is a normal double TNT Flexy, so it doesn't have a center column for a center speaker.
MyRoom_v3.1.4.2.png
 
ask Dave if he can dig up the drawings / photos for a CC for FE167E we did several years ago for "sprow" ( approx 10 liters IIRC)

I think the short answer is that a small sealed box would definitely be doable, and that the higher bass roll-off this would effect on the driver would not be a deficit in this application.
 
I can't recall the volume, but we used a volume that gave Q=0.7, F3=106 hz. It works well.It was designed for placement on a mantle-piece.

You might consider a box that acts as a "foot" to stand the television on.

dave

I calculated that volume from an old CAD sketch that I stumbled across

Just don't be tempted to reduce the depth of cabinet to the absolute minimum, which could be expected to cause internal reflections and coloration in the critical mid-range area on which the CC is intended to concentrate

The latter is certainly a lot easier with the current generation of moderately sized (36-42") flat screens that are at least half the weight of old CRTs ( my chiropractor remembers more fondly than I the last big Sony KVR set - felt like over 120lbs when you picked it up, and somehow got heavier the further you moved it :rolleyes: )
 

Crossblade

Member
2006-07-06 9:32 pm
Chris, what is the minimum depth I should do?
This is discussed here, but I do not find a straight answer http://www.diyaudio.com/forums/full-range/94519-fostex-fe-167e-flat-enclosure-fot-ht.html

Also, how many Liters is optimal for 167 sealed? :)

After I didn't find a suitable position for the center channel speaker (except BEHIND the rack), I am thinking about putting it in front of the audio rack when I am watching movie:D
This means, I can do an enclosure as high as 88-90cm (35"). Still, Fonken, Demetri and Chili are out, as they are like 100cm high. Any suggestions?
I prefer something smaller, as I can move it easier. If there is no great enclosure which is that short, I may do a sealed with minimum depth (so it doesn't bring the driver too close to me) a height like 88cm total and width to make the best possible volume.

Thank you again!
Nanko
 
Chris, what is the minimum depth I should do?
This is discussed here, but I do not find a straight answer http://www.diyaudio.com/forums/full-range/94519-fostex-fe-167e-flat-enclosure-fot-ht.html

In the case of the little sealed box pictured earlier, there were dimensional constraints, and per my archived sketches the number was 127mm.

It sounds as if you're far less restricted than that, so as deep as you can make it shouldn't hurt - but try to keep cross section from being perfectly square. As even a cursory review of the Fonken series drawings would indicate, we like to use GR proportions and/or irregular orthogonal shapes whenever possible.

Also, how many Liters is optimal for 167 sealed? :)

Thank you again!
Nanko
I think Dave as already suggested that "optimal" depends on application, and in this case I suspect the higher F3 invoked by a smaller enclosure might work in your favor
 
Great info Dave!
Is there any enclosure for the 167e that is shorter than 90cm (35.5")?

p.s. please reply to my email when you have time ;)


I'm not sure if Dave had made revisions or publicly released official drawings of the Fonken167 (the discontinuation of the driver made that moot), but as you can see from the attached photo there is a substantial lower void cavity intended to eliminate the need for short stands, and placing the driver center at approx 766mm from floor. Indeed, some builders have modified the plans to accommodate a separate woofer in the lower cavity.

The net volume is approx 27L and depending on material thickness and treatment of base plate, etc., the height of active enclosure is approx 665mm.
 

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I was planning on doing the Fonken, but now decided to go with the much simpler Seasled.

Guys, please give me last advice - which is the best Volume?
You told me there is good result with 10l and it shouldn't be bigger than 23l. Will the biggest (23l) give me lowest bass, and will it have any negative sides when compared to the smaller 10l one?

I guess Bigger is Better (once it is in the limit) but ...

Nanko