komeback little karlson (any Karlson activity?)

K15 midbass pair up and running, posted on September 13, 2009 at 22:56:06
keto Audiophile Posts: 1006 Joined: September 29, 2001	I now have a boomin' bloomin' pair of K15 copies up and running. The sound is growing on me. Drivers are Lambda TDM15 Apollo's.

RE: K15 midbass pair up and running, posted on September 14, 2009 at 06:36:09
freddyi Audiophile Posts: 3866 Joined: December 6, 2001	for fun you could whittle a 5.25" long 1" inside diameter Karlson waveguide tube with half-ellipse slot and 1/8" starting gap to run on top as a two-way - - there's a lotta of interaction in bass/midbass k's with regards to subjective effects of the aperture and the initial opening width Karlson Evangelist

RE: K15 midbass pair up and running, posted on September 14, 2009 at 09:37:23
keto Audiophile Posts: 1006 Joined: September 29, 2001	What's your favorite 1" driver? Any chance one could get away with a 1st/1st passive XO, say, around 1K5hz?

RE: komeback little karlson (any Karlson activity?), posted on September 14, 2009 at 13:54:01

zobsky
Audiophile

Posts: 569
Location: dallas, tx
Joined: June 11, 2005

well, .. a buddy left his K15 at my place for a while and we've been experimenting with it loaded with with a 4 ohm pyle pym1298 or an 8ohm eminence sigma pro 18 !! Not much difference in either for sub duty, .. not much below 35 - 40 Hz, but above that, it's subjectively cleaner / punchier than my current HT sub- a fitzmaurice table tuba loaded with an MCM 8" . I haven't found my measurement jig yet but I have some unscientific measurements with a RS SPL meter , and the drivers powered by a plate amp (which likely has some built in boost ). Any of these arrangements can easily bring the house down with the 100 watts or so available.

I'll try and post the measurements / some cell phone pics later.

I see pym 1298 K12 in my future for 70 - 400 Hz duty.

RE: K15 midbass pair up and running, posted on September 15, 2009 at 16:10:19
freddyi Audiophile Posts: 3866 Joined: December 6, 2001	Eminence would work, B&C are cool, cheap Selenium usable - whatever you might have laying around - you could try 1st order - it might be ~3rd order acoustic - it would be hard on the driver at higher peaks - but that's what Karlson did in his 1965 X15 with internal slotted tube wavegide Karlson Evangelist

RE: K15 midbass pair up and running, posted on September 15, 2009 at 16:58:32

kenpeter
Audiophile

Posts: 450
Location: Dallas
Joined: August 27, 2007

Zobsky and I continue the occasional Karlson experiment...

Pulled my Sigma18 from 1955 K15 w 12inch hole in baffle.
Please don't ask how I got the 18 to fit a 12 inch hole.
It was conjested and lost its kick, compred to earlier
DeltaPro 12. Don't know if the Sigma too big for the K15,
or just the 12 hole was choking the bigger driver to death.
Did get some phase plug effect from the undersized hole I
think. Upper mids were decent for 18.

And we installed Zob's 12 inch PYM per your suggestion to
do some measurements. But not using all the bolts, so its
sometimes a rattle... Doing OK against BillFitz 10, but
the BFM horn loads lower than K15 in a corner.

Plans are to open the baffle to properly fit the Sigma.
If that don't get the missing "hit" back, then new boxen
with taller coupler, probably not much wider than K15...

Zob wants to build a Smith horn.

RE: K15 midbass pair up and running, posted on September 17, 2009 at 11:27:12

freddyi
Audiophile

Posts: 3866
Joined: December 6, 2001

I had good luck with low Q lower mass 18" Eminence stuffed in ~K15 volumes - just a bit of loss vs K15 at 50Hz and a bit more around 60Hz - bulk for bulk any T-line including inverse taper can have more LF than K15 as K15's LF imo is dictated by its rear chamber volume and tuning vs parameters

here's inroom LF of an inverse tapered line with heavy cone 15 (Dayton 295070 ~like 2226 TS) vs NIrvana Super10 in K15 - overall builk is pretty much equal for the two types - I think the K could measure cleaner with two tone testing depending upon the tones picked :^) - as you can see from the inverse taper T-line's red trace with a full opening that hybrid k-t-line could be built

Karlson Evangelist

Koupler mods..., posted on September 29, 2009 at 17:50:03

kenpeter
Audiophile

Posts: 450
Location: Dallas
Joined: August 27, 2007

This is prolly what I'll be tryin with the new K18 tallboxen...
Going 4ft high x 24.5 x 20. Just cause I'm lazy with the saw,
and 20 fits thru my door. Beides, its not exactly like an open
rectangle inside...

K15 works with Sigma 18 now that I got the hole resized for it,
though some internal butchery of rear shelf and bottom happened.
As the K15 speaker baffle is only just barely tall enough for 18.
New K18 baffle will obviously need to be taller too, and that may
change the angle slightly...

Maybe why Khyboe eliminated the shelves?? I don't know what they
were thinking... I still think the shelves are necessary to move
down the frequency of that acoustic short circuit. From the back
of the driver to the front...

Anyways, I plan to bend Fig 6 into a full arch. And turn the shelf
sideways. Both mods intended to give additional brace for the wings.

I think Karlson wanted the path lengths of the reflections in the
upper koupler to come back together in phase at the slot. That it
might radiate more like Carl's fantasy of how it ought to. I don't
think thats ever gonna be possible with too many different path
lengths up the middle, not even with Fig 6 reflector. But give two
equidistant paths up the sides.... Hey, we might have something?

RE: Koupler mods..., posted on October 4, 2009 at 17:08:23
kenpeter Audiophile Posts: 450 Location: Dallas Joined: August 27, 2007	First attempt at Google Sketchup. Some mistakes are evident and not too easily correctable at my current skill level. Probably have to start over... Cabinet 2 and a half inches wider than I realized, the first of many big oops. Upper Koupler looking like Crosley radio turned inside out ?!? Wasn't exactly the shape I was trying for... Not satisfied yet. Back to the drawing board.

RE: Koupler mods..., posted on October 20, 2009 at 17:20:22
kenpeter Audiophile Posts: 450 Location: Dallas Joined: August 27, 2007	Tweaking on it some more.

RE: Koupler mods..., posted on October 20, 2009 at 17:23:25
kenpeter Audiophile Posts: 450 Location: Dallas Joined: August 27, 2007	And more tweakage... Too tall this one, focus too far above the slanted shelf?

RE: Koupler mods..., posted on October 20, 2009 at 17:25:34
kenpeter Audiophile Posts: 450 Location: Dallas Joined: August 27, 2007	Wish I could sKetch old fasioned violin f-holes, or bats...

RE: Koupler mods..., posted on October 20, 2009 at 19:08:33

freddyi
Audiophile

Posts: 3866
Joined: December 6, 2001

really dunno what will happen with Fig666 - "Fig6" approach in X15 seems to intensify the ground-plane dips (?) - not sure of it's effect upon the on and off axis response (JanS liked the sound of his Fig6 couplers) ----in opposition to K's patent, a perpendicular board might "sometimes" give a smooother graph. Ray-tracing with curved reflector per Fig6 is supposed to keep reflections off the cone and minimize destructive interference. Do the dips negatively impact the sound much? Does Fig6 style reflector focus some of the front upper coupler's midrnage and treble slap echo though the aperture "better"?
Karlson Evangelist

RE: Koupler mods..., posted on October 20, 2009 at 20:59:48

kenpeter
Audiophile

Posts: 450
Location: Dallas
Joined: August 27, 2007

Thats the idea. Constructive interference focused into a vertical
stripe, directly behind the K slot. Maybe more of the sound will
make it out on the first pass? Hopefully reducing reverb issues.

Fig. 6 always seemed to me that it focused to a horizontal stripe,
unable to pass efficiently through the front opening.

This may be technically a "high order mode", where sound from the
left and right edges of the shelf crash back together... But done
for a plausible good reason??? If it actually works, that is.
I won't know till one is built.

Long list of stuff to do.

RE: Koupler mods..., posted on November 10, 2009 at 08:38:55
kenpeter Audiophile Posts: 450 Location: Dallas Joined: August 27, 2007	Fig.999 view#1

RE: Koupler mods..., posted on November 10, 2009 at 08:41:42

kenpeter
Audiophile

Posts: 450
Location: Dallas
Joined: August 27, 2007

Fig.999 View#2 (with the bottom access plate off)

RE: Koupler mods..., posted on November 10, 2009 at 08:48:36
kenpeter Audiophile Posts: 450 Location: Dallas Joined: August 27, 2007	Fig.999 Build plan. (Note: left angle piece in back was drawn redundant for dimensional clarity) (If you were to cut as many pieces as shown, you'd have one left over...)

RE: Koupler mods..., posted on November 10, 2009 at 09:15:50
freddyi Audiophile Posts: 3866 Joined: December 6, 2001	looks good - what do you expect for the results of: (1) rear panel braces which also taper upwards in area? (2) the two brace's guides with circular cutouts? (3) truncated width front-shelf? Karlson Evangelist

RE: Koupler mods..., posted on November 10, 2009 at 16:55:14

kenpeter
Audiophile

Posts: 450
Location: Dallas
Joined: August 27, 2007

So for the moment throw out everything Fig.666 theoretically
does for full range. The Fig.999 Koupler entirely about bass!
Wether it works or not is still subject for build it and see...

Taking the Metro T15 style folded stub to its most absurd?
The entire box is a folded stub! Horn loaded to the point
where the waveguide expands no further. Exponential K slot
loaded from that point forward into the larger volume of
the room. I won't know how smooth the K loading takes over
from the horn till one is built. All imaginary for the moment.

Obviously I've had to sacrifice the curved reflectors that
formed the upper chamber of the Fig.666. But I did retain
the high order mode shelf, if only for the added bracing.
If those modes still align behind the slot would be bonus,
but not part of the design criteria.

High Efficiency Speaker Asylum

komeback little karlson (any Karlson activity?)

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