Fostex FE206En speaker box build all options? Building for a friend.

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#24
BK20 is about the smallest usable blh for FE206EN.

As mentioned before, I prefer a Karlson. But you may not. Karlson's K8 is simply too small to work without a sub. A bit larger will work. A K10 size at ~20.4"Hx14"W x 11.25D is pretty good. It plays well enough in a Karlson 12 (1954) and preferable to my Klipschorn. K12's never changed outside dimensions, and only a little inside from 1954 until Karlson's death in January 1973.

here's what looks like a clone of a factory 1960's K8 loaded with FE206EN
- tuning is near 95Hz IIRC. The speaker must have been installed before the aperture plate was fixed.

https://www.youtube.com/watch?v=CLhQClWJEBU

https://www.youtube.com/watch?v=I_is--dMAH4
 
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#26
freddi said:
BK20 is about the smallest usable blh for FE206EN.

As mentioned before, I prefer a Karlson. But you may not. Karlson's K8 is simply too small to work without a sub. A bit larger will work. A K10 size at ~20.4"Hx14"W x 11.25D is pretty good. It plays well enough in a Karlson 12 (1954) and preferable to my Klipschorn. K12's never changed outside dimensions, and only a little inside from 1954 until Karlson's death in January 1973.

here's what looks like a clone of a factory 1960's K8 loaded with FE206EN
- tuning is near 95Hz IIRC. The speaker must have been installed before the aperture plate was fixed.

https://www.youtube.com/watch?v=CLhQClWJEBU

https://www.youtube.com/watch?v=I_is--dMAH4
Click to expand...

Thank you for your post. I will show my friend but it's up to him now. Thanks Jeff
 
#34
As GM says, it would be useful to know what the amplifier is. The 206, while a good driver of its type, is not especially well-suited for use in a standard vented box (not if you want any LF out of it) unless used with a high output impedance amp or suitable series R (which is what Fostex assumed when they designed it). Too low a Q, too high a mass-corner. Corner-loading would help. But it's a nominally limited travel design -it has plenty of mechanical excursion; linear excursion is more open to question (Xmax is almost useless unless the manufacturer tells you which method they used to put a number to it), and is of limited value even with that.

Some form of horn loading or a BP type like the Karlson should give more usable results with the 206 than a regular vented box. That does usually mean more woodworking though, so if that's out of the question and the amplifier is not a SET type, try about 2.5ohms - 4ohms series R and design using the artificially raised Q. Based off the Fostex plot & doing some swift mental arithmetic, 4ohms should kick the nominal maximally flat (I don't recommend maximally flat, but it serves as an example) box Vb up from approximately 6 litres to about 4x that, with Fb for a similar alignment being about 50% lower.
 
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#35
Bob Brines said:
Unless I am totally wrong, the Fostex FE's are all underhung and will only move so far as the coil will be entirely out of the gap. You will get really impressive dynamic compression just before they catch fire.

Bob
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Now that would be a dramatic finale! Sounds like something I would do. Well it was only for a few seconds and I had my hand on the volume but still not a good idea I guess. I don't know of any FR design that could play organ satisfactorily without a sub but still I believe the half-changs can play most music at reasonable levels with very good bass and is a fairly easy build. I'll put them in a k12 and compare.
 
#36
one thing to consider in a K12 would be the choice of vent type - whether to go with a distributed slit/slot/hole array or a single vent. Under sine conditions, the distributed vent with narrow slits will distort. Whether that happens with music = ? Karlson's first K12 (1954) had a 15/16" high horizontal slot vent. In 1956, the 6-slit 10 degree vent board variant shown in July 1958 Popular Mechanics appeared. I have a pair of later 60's K12 with 4 -slots less constricted than the usual 6 type. Karlson offered a K12 with a blank port board and (maybe ?) instructions on drilling hole arrays to suit particular drivers of its day.

one could use a squarish 12 sq.in. single vent in K12.

the first K12 had a rear chamber adjustable tightness lowpass choke, that re-appeared for the K12 with the hole array vent.

FWIW I've run FE206EN in K-coupler smaller than K12 - K8, a taller version of K8, 0.62 scale K15. K8 needed help on the low end - getting up near one cubic foot in the rear chamber was better. One cubic foot rear chamber can be good for some powerful 10" woofers.

all I have for FE206EN sound clips are with a 0.62 scale K15 - about a "K10"
- I normally have the 0.62 scale loaded with Beta10cx - that speaker has a clobbering amount of output in the 100-200Hz region - Beta10cx could use at least another pound of magnet to bring up its midrange.

Here's approximate dimensions derived from a brochure sketch on the K12 which came with blank port panel plus two pictures

https://lh3.googleusercontent.com/b...Nch9WPi22EzT4Wlc3-DAhdWAgEow=w1280-h800-rw-no

http://usr.audioasylum.com/images/6/66574/University_200_0021.jpg

http://i.imgur.com/ip5l9A0.jpg


"SK8" tast tapers, Eminence Delta pro 8a, Dayton 250p on "The Tube" - drumkit (John French)
https://www.youtube.com/watch?v=T71pRwTGfuc
0.62 scale K15 with FE206EN - soprano and harp
https://youtu.be/NaWvtfI6FiA
0.62 scale K15, FE206en - drumkit (John French)
https://youtu.be/GpGkYpAcUdw
high aspect K8 with W8-1772 - sax
https://youtu.be/z1RYpD9MrV0
high aspect K8 with 1772 - Steve Clarke drums
https://youtu.be/LuNOzlQAVlw

with w8-1772, the high aspect K8 which has about the same bulk as K12,
had 2-5dB less output in the 110-220Hz octave than 1772 in K12.
 
#38
k12 with good 12cx or woofer + K-tube sounds better live/ion-person than my Klipschorns - K-horn go deeper but have worse overhang and other problems.

k12 with FE206EN will play pretty well - it might be good to keep the rear lowpass shelf then tweak that feature

I don't know how FE206EN would play in a Karlsonator 8- might lose some "hit" vs K10 and K12 (can't remember if xrk971 simulated that case -?)
 
#39
GM said:
Didn't notice what the amp is, which if SET could make moot some of what's been suggested. Ditto max average, peak SPL and location desired in room location.

GM
Click to expand...


Sorry for any late reply. The amp is a PS Audio amp and pre amp combo about 15 years old. I don't know about the wires that are being used? He is using a sony CD player for now and for records his record player is broken so that's on his list to fix things. He has other solid state receivers but, I told him to stick with the P.S. Audio stuff. Still waiting to build the boxes? Jeff
 
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