Contemplating This Fostex Fe127 Project

[JimOfOakCreek]

I am contemplating building the attached Double Bass Reflex Type Enclosure for a Fostex Fe127. The project is recommended and designed by Fostex. I think I can build this cabinet. I'm going wait until the weather warms and do the cutting out of doors.

I want to build it using 3/4" MDF. I built a sub cabinet in my basement but the MDF dust was too obnoxious, hence my reasoning for doing the actual cutting out of doors.

My question is this. What do the experts think of the attached project for a newbie builder? Any thoughts about the sound?

[TerryO]

Originally posted by JimOfOakCreek
I am contemplating building the attached Double Bass Reflex Type Enclosure for a Fostex Fe127. The project is recommended and designed by Fostex. I think I can build this cabinet. I'm going wait until the weather warms and do the cutting out of doors.

I want to build it using 3/4" MDF. I built a sub cabinet in my basement but the MDF dust was too obnoxious, hence my reasoning for doing the actual cutting out of doors.

My question is this. What do the experts think of the attached project for a newbie builder? Any thoughts about the sound?

Jim,

I'm not sure what the experts might think, but it looks fairly simple, so why not? You'll gain some experience constructing a speaker cabinet and it'll give you something to listen to while you build one of the Frugal site designs.

Just remember that the "experts" are usually those with a fair amount of experience, and experience starts the moment you begin.

Best Regards,
TerryO

[ttan98]

Planet 10 is the expert on this driver, he may you recommend the Fonken cabinet, with more bass and few other mods to consider at a later stage.

[chrisb]

Originally posted by ttan98
Planet 10 is the expert on this driver, he may you recommend the Fonken cabinet, with more bass and few other mods to consider at a later stage.

gee Terry, since I've built at least 8 different designs for this driver, does that make me an "expert"? Frankly, this driver is capable of much more than either of the "factory recommended" enclosures can deliver. The same can be said of the FE126E.

"Fonken" has really morphed into a family of enclosure designs of different configurations, but using essentially the same loading/ tuning criteria. Dave might want to elaborate on that detail - I just build and listen to them. The original multi-slot port, bevel sided cabinet is by far the most PITA construction of the bunch, but still edges the others out by small margins in delicacy of lower midbass & down articulation. They are my "daily driver", well sited they can do quite the disappearing act.


For a builder looking for a relatively easy project using the FE127E, I think it's fair to say the "Classic GR" or "Floorstander MkII" would be a safe bet. The latter can particularly be made very wife friendly, and don't need stands, but due to their very narrow baffle, could require either BSC ( ) or corner/boundary loading. (and don't forget the sand / shot ballast or enlarged plinth - they can be more than a bit tippy)

A slightly larger pair of enclosures (as in wider) that squeeze a bit more low end extension from the FE127, at the price of refinement, and with the risk of exceeding the driver's X-Max when overdriven in a large room, are the Mileva and Brynn. These are also floorstanders, and with the appropriate cosmetic treatment, can earn huge WAF points, and sound excellent.


and please, if not plywood, then at least particle board instead of MDF

As for maximizing the bass from this driver - careful how you approach that - you could well sacrifice what it does so well from the lower midbass up. Outstanding performance can be achieved with ScottMoose's BVR designs - i.e. the Brynn could be considered a "half-sized" enclosure - I can assure you their is nothing pint-sized about the sound! However, for those domestic situations wherein a 60" tall double mouthed horn might be a hard sell, another approach would be a pair of active woofers crossed over anywhere between 80 -120Hz . The new CSS SDX7 is a dynamite performer, and works great in pretty small sealed enclosures, and sub amps are so damned cheap these days .....

[planet10]

I've not heard the Fostex double bass reflex. I am a bit predudiced against BR nature (since T/S parameters change i feel it important that any vented enclosure counter these changes).

That said the few references i have seen of people building this box reported favorable results. One particular execution struck me as particularily nice -- attached below.

The PITA Fonken is still the best box we have managed to make* for the FE127, but all the others have not been slouches. Seems to be one of those boxes it is some work to make a bad box.

*(we've done PITA Fonken, GR Fonken, FS Fonken Mk II, Mileva, Brynn, mFonken (& 2 prototypes), straight bipole diyRef ML-TL, folded monopole diyRef ML-TL, Fostex Hybrid TL/BR (not that good). We haven't tried it in the Frugel-Horn but that would be fairly easy. Would like to try Metronome, bipole Met, Curvy Gabriele, Odessey (this one should rock), iBIBk, and we are playing with the idea of a bipole Mileva -- right now we are concentrating on helper woofers for the Fonken, mFonken, µFonken)

dave

and sounding like a broken record, no MDF please

[Bluto]

ChrisB-

" If not plywood, at least particle board".

I thought I'd read every thread every where on this subject and though I agree regards baltic birch I don't think I've seen your statement before. Why? You can't run a router on particle board, it'll chip so roundovers are out and it's lighter so I'd think sonically not as tight.

Bluto

[chrisb]

Originally posted by Bluto
ChrisB-

" If not plywood, at least particle board".

I thought I'd read every thread every where on this subject and though I agree regards baltic birch I don't think I've seen your statement before. Why? You can't run a router on particle board, it'll chip so roundovers are out and it's lighter so I'd think sonically not as tight.

Bluto

guilty of chumming the waters....


It can't hurt to try thin particle board (1/2" or 5/8") with strategic hardwood or plywood bracing - it could sound faster than MDF . Why is "lighter" necessarily not "soncially tight", or even a bad thing for a full range driver enclosure?

The quality of joinery and assembly will have at least as much impact on the musicality of the sound the enclosure contributes to the system as the material.
Having said that, my experience with multiple versions of at least 3 different enclosure designs has lead me to the conclusion that some materials are more "noble" than others. For example, 3/4" bamboo plywood is lighter than 1"MDF, but is an absolutely brilliant material for loudspeaker enclosures.


Can't run a router on particle board - maybe you're thinking of OSB? A large percentage of melamine, PVC or thermofoil wrapped panels used in lower grade furniture are particle board core, and include a lot of routed / shaped and machined profiles edges, and even glue-lock mitered joints.

Sure the exposed grain would need much more prep for paint grade finish,(or will absorb more glue than MDF) Proper finishing of even high grade MDF takes skill and once you fully account for the time and materials, can cost more than veneering. Of course, I'd prefer the speaker cabinet to look a much like real wood as possible, and that's what works for me.

[JimOfOakCreek]

[i]

and sounding like a broken record, no MDF please [/B]

Baltic birch plywood it is then.

[JimOfOakCreek]

FYI: There are some dead links on the Planet-10 commercial site. I went there to glean some information and found many of the links to the box plans dead. There are other dead links as well. After a winding trail of links I did manage to download several box plans.

An interesting site. I didn't realize that Fostex speaker drivers could be modded for higher performance. Interesting!

[planet10]

Originally posted by JimOfOakCreek
FYI: There are some dead links on the Planet-10 commercial site. I went there to glean some information and found many of the links to the box plans dead.

Let me know which one -- i checked all the fostex plans (and fixed one that has moved)

dave