XKi - X's ab initio Karlson 6th Order Bandpass

[freddi]

until X replies, --

what kind of amplifiers do you use?

original K12 all tune around 60-62Hz - fe206en had a robust and lively presentation in the old K12 (aka "Karlsonette") .


I have run FE206EN in K-coupler smaller than K12 (~"K90->K10" in size and it still had an attractive midrange. GregB's Karlsonator8 is tuned about a half octave lower (~42Hz) than the classic K12. I'm not sure what that lower tuning does to the low end - xrk971 could make a reasonable simulation.

here's GregB's kluged simulation done some years ago for FE206 in the Karlsonator8 - dunno if it would be that strong on the bottom (?)

Fostex FF225K

 

[xrk971]

FE206 has low Qts so best for XKi if you want deeper bass extension.

 

[Vix]

Yep, I was afraid that Fe206 won't go low enough in Karlson 12, but it might do in Xki. Amps are low power Class A, Pass Zen V9 and/or Sewa (7 w mosfet follower)...

 

[freddi]

do you listen to a lot of music which "goes low" ? - bass drops, low tuned electric bass, pipe and electric organ, etc. ? the "bass" you do get with a K12 & FE206EN is pretty impressive for an 8 inch driver. Some of my Taiko drum CDs were pretty good tone-wise - sounded like my 26 inch Ludiwig and more solid than a little BLH. (The BLH sounded like the initial hit and its bass were not in time and spatially "disconnected" - - no punch ) I'm interested too in what xrk971 has to offer in an XKi for FE206EN.

 

[Vix]

Yes. I had and still have sealed boxes (with CSs125fr), had ML TL with 8" drivers (tried various ones) and currently use Open Baffles. As with everything else in life, it is difficult to find something that provides everything. With sealed boxed I like transient response (unlike BR), but they miss some life and slam, also don't go very low, ML-TL sounded nice, went low but in my opinion it lacks some midbass and is not well suited for rock music. Open Baffle is a love and hate relationship due to its inherent strenghs and weaknesses. Some Backloaded horns I also didn't like (of other people) because I felt like there was some coloration/time delay in the bass. Now I am wondering wether it is possible to build a speaker that has that fullrange magic, does the kick and goes low. Too much, I know. Yet, Fe206 in Xki migh perhaps provide all that...

 

[xrk971]

Let me run a sim of FE206 in an XKi for you. Did you ever provide me the TS parameters?

 

[freddi]

if his version is FE206E then



Def_Driver 'FE206E" | Fostex 8 inch full range speaker
SD=206.1cm2
fs=39Hz
Mms=15.35g
Qms=3.73
Qes=0.18
Re=6.69ohm
BL=11.82Tm
Le=0.3mH
Vas=54.53L

 

[Vix]

Yes, it is the FE206e, with the above parameters.

Thanks!

 

[xrk971]

Yes, it is the FE206e, with the above parameters.

Thanks!

Try using a 24 liter box, 80% volume in rear chamber, 20% in front chamber, make the box 10in wide (internal dimension) with a 10in wide x 0.75in deep x 10.0in long vent. This gives it a F3 of 50Hz and can handle about 8w rms before hitting xmax. Make front K aperture following usual guidelines. Wings should open up and intersect driver surround when viewed from front.

 

[freddi]

24 liter airspace = that's a real nice size - 206 seem very graceful at + - 2mm - it will be interesting to see the drawing and build

 

[xrk971]

I like the 24L 10in wide format too. My main RS225/10F speaker is 24L and looks nice.

 

[freddi]

would you make the inside height ~14"?

 

[xrk971]

Probably 15in high and ~10in deep.

 

[freddi]

- so the front chamber about 4" deep at its top (?)

 

[xrk971]

- so the front chamber about 4" deep at its top (?)

Yes. The math works out that way - for 20% front chamber, depth needs to be 40% of total so 10in x 0.4 = 4in.

 

[freddi]

so the finished build will be about 12" deep x 11.5" wide by 16.5" tall - 5/8" BB or 3/4" "Araco" plywood. 1/2" BB might suffice with a few braces. It would be nice to make the wings rather "dead" from some laminate.

I've only one FE206EN so an XKi might be the 34 liter version for SN10C. The 60 liter XKi for 1772/Beta10cx is a bit big for my little bedroom.

 

[xrk971]

I think 1/2in BB would be nice to keep the bulk down.

 

[freddi]

the FE206 XKi is just a bit larger than Beta8cx XKi

Beta8cx in the XKi should sound pretty good on female vocals when things are right

would FE206EN XKi's aperture look as "constricted" as with the image above?

 

[xrk971]

That plan for the Beta 8Cx looks almost about the same as for the FE206E. Vent is also 0.75 deep but 10.0in long. Cabinet on FE206E is an inch taller and depth an in deeper, with a 4in deep setback on the front chamber.

 

[freddi]

with some foam blocks in the rear chamber, the Fostex version could also accommodate Beta8cx (?) - - (maybe others ?)

out of all of your K models - which one might you most easily add a stub feature to the front chamber? - Could that be useful to quell the peak seen right before the "W" fill area in K15 type? Is it useful on the XKi where the sim shows substantial rise to a peak ? (typically 200-300Hz)