Power handling concers for the FE127E


2008-01-08 2:24 pm
I am looking into building a speaker set using the fe127e, but I am concerned about overdriving them. The xmax is pretty low, and I am worried that they will bottom out easily in an enclosure like the BIB (no back pressure right?). They will be my mains in a home theater/ music system. They won't see anything below 100hz, and will be paired with an MK sub that my dad gave me :D

Any thing will be better than the plastic cubes I have now. Thanks to this wonderful forum I can't make up my mind on an enclosure. After reading forever I decided on the BIB, although the Harvey looks like a lot of fun to build. How do they sound?

thanks in advance. I've done some searching but haven't found specific answers.
Used within it's limits, this is a wonderful driver. If the HT receiver has full bass management EQ, and the signal to mains is set to "small", you shouldn't run into problems at "moderate" listening levels (i.e. below 96dB) . For that matter, it makes for a marvelous center channel as well, if you're so inclined.

I'd suggest a small aperiodically damped enclosure such as one of the Planet10 Fonken designs. They are intentionally tuned for higher roll off, and offer tighter control over bass excursion (i.e. less ripple) than the BIB, or conventional bass reflex designs. The GR "classic" rectangular box or milliFonken slot loaded are much easier builds than the large bevel sided Fonken - bear in mind that any of these designs need stands.


If you'd rather avoid the cost of stands (good ones can easily cost more than the drivers) - the Brynn(Chang) is a relatively compact footprint and fairly easy to build BVR design which sounds excellent as well. The lower void chamber behind the slanted baffle needs additional triangular bracing to the back panel that is not shown on drawing.

I don't have experience with the super-sized Gabriel Chang , but as you've already indicated sub(s) will be used, the extra bass impact from double mouth format would probably be redundant.

Let me chime in here... if you only need bass down to ~100 Hz, the BIB is not the best choice...

The whole reason for the BIB is to get as much bass as possible out of a driver. The compromise for its excellent bass extension is ripple, size, and the requirement for corner loading. i'd expect sub 40 Hz out of an FE127 BIB. to cross it over at 100 Hz you would still be paying for the compromises while throwing out its advantages. Same applies to Harvey (althou it likes to be out fom the walls).

With a 100 Hz requirement you would likely find something that goes to 100 Hz or so a better choice -- this will give you more midrange finesse. If the box doesn't go much below 100 Hz, a simple 1st order PLLXO can be used for the roll-off on the bottom so that you insert no extra active circuitry.

Rolled off at 100 Hz thou you are not likely to have excursion issues with a BIB. Something like the mFonken which is very specifically tarageted at this kind of application would hasve fewer compromises for this ap (and use less resources). Now if visual SLAM is important the mFonken won't cut it, but on the other hand WAF is HUGE :)

What is your amp?

The doubled designs do indeed tend to give more subjective puch to the sound, but more significant IMO is the superior front-back imaging & scale over single-mouth types. Great for piano. More complicated & larger of course.

The problem with the smaller BIB cabinets is loading them right. The large ones (~70in tall) genuinely don't suffer from much response ripple at all once correctly located in corners, because they're properly coupled to the room & the horn flare is completed. The smaller ones (any driver with an Fs over ~60Hz) have a much harder time of it. Upward venting is pretty much a waste of time with them -they're far too far from the ceiling for the expansion to be continued properly by the room, even in corners. Inverted is better, but they do need to be right down on the floor in ther corners to get the coupling they need.

Given that nothing under 100Hz is wanted, then overall, I'd be inclined toward mFonken.


2008-01-08 2:24 pm
Thanks for the responses. Good to know that I don't necessarily need a BIB for what I would be using it for. The thing is I may use it full range someday. The other thing is that BR and sealed enclosures are no fun to build :D I'm kind of a tinkerer, so building a crazy enclosure is a lot of fun for me.

My amp is a middle of the road Sony HT amp. It does have the "small" speaker setting which as far as I know is set at 100hz. Thanks for the advice about the Fonkens. I may go with them if I can get two out of one sheet. For the center I was going to use the same driver in the recommended BR enclosure, but with the port in the back so that the driver can be in the center.

BTW, I stumbled on this DIY speaker stuff completely on accident, and it seems to want to pull me in!
JJ77 said:
Well I've looked around again. Would there be any compromises to using the floorstander MkII? Tall enough to not need stands, and less wood.

No real compromises compared to the mFonken (but better bass), not quite as much finesse as the full-fledged fonken (i expect mostly due to those big champhers on the front). The whole point of the Floorstander was to create a speaker with a VERY small footprint that reached the floor on its own. The Mk II was done to counter the somewhat tippy nature of the MK 1 (do fill the bottom with sand/lead shot/kitty litter.



2008-01-08 2:24 pm
Thanks to everyone for the advice. It's especially nice to hear from all the knowledgeable folks about different solutions. It's also nice that so many designs are available for free instead of being kept secret to make a little extra $.

I've found a solution to my indecisiveness. I'll make the FSII's, then later Ill make a small amp and try something for the 103's.

thanks again.
Re: Re: Floor Standing Fonken

planet10 said:

That one was really more of a thot experiment.


too much fonken around, and not enough building - there are several other enclosures in this particular size range that also work quite well with the FE127E - Tom Z's PAWO, and the Mileva - the latter of these the easiest build of the group.

Dave - I tried to attach one of the composite photos of the walnut towers from earlier this week - file size is too large.

Maybe you could perform some presto changeo to post either of these.

With the addition of a sub, I'd wager these would sound excellent indeed - certainly much bigger than their physical size would suggest. Visually they are certainly the opposite of any of the HGH-enhanced double mouth BVRs/horns or BIB, and granted may lack some of the scale of the big boys.

OTOH, there is the considerable advantage of easier installation - no corners or stands required, and they certainly don't take up much floor space. In my own domestic situation, the interior decorator aspect in the AV room is of primary importance.
Re: Floor Standing Fonken

gurley123 said:
You could try these: http://fullrangedriver.com/forum/viewtopic.php?id=533 post #20.

A little more wood but really good looking(I think).

Thanks to P10 for giving us (almost) too many to choose from.

OTOH The MKII looks like an easier build.

yes, there are too many concepts for "us" to build them all

the MKII FS is indeed one of the easier builds of the Fonken family - and certainly doesn't use a lot of material
Re: Re: Re: Floor Standing Fonken

chrisb said:
Maybe you could perform some presto changeo to post either of these.


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