can we manipulate response by picking front chamber shape and aspect? sometimes with the original K, there's some climb in the "hit region" - from indoor response traces, a skinny (28"H by 13.5"W by 12" D) K-coupler had 2-5dB less output in the 110 to 220Hz octave than the old K12 when both were loaded with a Tang 1772. It could be useful for the builder of new couplers to see if there's some generalizations to be made for several aspects so they could mentally balance the effect vs simple bandpass kludges. Hopefully there will be some Karlsonator 6, 8 and larger builds to compare vs akabak sims and K15. BTW, does the Karlsonator behave different in simulation than the "same" cabinet with a reflex vent above the driver?
FWIW I think both the 28" and 20" tall 8 inch K-couplers built in the last few years were good performers and better in ways than direct radiators - initial gap and aperture flare have more effect on tone overall than what will show in a simple one-mic graph. There should be some good new K couplers in-between these two heights.
If you ever get time, I'd like to see a simulation of the Acoustic Control 115BK K-coupler. I'd recommend it and a K-tube as an alternative to a midbass horn.
FWIW I think both the 28" and 20" tall 8 inch K-couplers built in the last few years were good performers and better in ways than direct radiators - initial gap and aperture flare have more effect on tone overall than what will show in a simple one-mic graph. There should be some good new K couplers in-between these two heights.
If you ever get time, I'd like to see a simulation of the Acoustic Control 115BK K-coupler. I'd recommend it and a K-tube as an alternative to a midbass horn.
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- no hurry whatsoever - by 'BR" - meant a standard Karlson vent vs GB's Karlsonator. The one example of the 13.3"W by 28"H x 12"D cabinet with horisontal slot vent vs the factory 1954 K12/"Karlsonette" gave 2-5dB more output in the 110Hz to 220Hz area than the skinny coupler with a W8-1772 - in other words I think the original K had more output in the upper "hit region" and the skinny K-coupler was more flat/neutral. 1772 should be good in certain K's and sounded good in the little (13.5"w x 12"D x 20.5"H) "SK8" (Super K8)
its strange to me that Karlson remain unexplored - if I had better health and woodworking skills plus space, then I'd do a lot more.
its strange to me that Karlson remain unexplored - if I had better health and woodworking skills plus space, then I'd do a lot more.
OK, I understand. BR is a like a 4 letter word around here 
The standard Karlson (e.g., K15 from 1955) cabinet is very efficient. The K'nator is not as efficient but has deeper bass extension. So there is a tradeoff as usual. The K15 also has a cleaner near ideal impulse response so percussion instruments like drums, plucked bass, piano, etc will sound more natural. The T15 design that I was working on with Anthony Bisset appeared to be closer to standard Karlson but with reach down to 40 Hz. It is more of a dual chamber than triple chamber design. Still remains to be seen if my predictions are true though - Anthony said he will get around to building one.
The standard Karlson (e.g., K15 from 1955) cabinet is very efficient. The K'nator is not as efficient but has deeper bass extension. So there is a tradeoff as usual. The K15 also has a cleaner near ideal impulse response so percussion instruments like drums, plucked bass, piano, etc will sound more natural. The T15 design that I was working on with Anthony Bisset appeared to be closer to standard Karlson but with reach down to 40 Hz. It is more of a dual chamber than triple chamber design. Still remains to be seen if my predictions are true though - Anthony said he will get around to building one.FWIW, the Karlsonator was originally an attempt to get more bass extension from 12" and smaller drivers than the original K12 and K8 enclosures. K15 is bigger, so no fair!
The relatively taller front chamber (of both mine and others' K-variants) was intended primarily to keep front chamber tuning closer to that of a K15. Nobody has figured out how to make a shorter bass wave.
I'd suspect that the traditional K12 might subjectively have "more hit" because the front chamber has more volume and aperture area. Fiddling around with BP models shows than increasing volume also increase output and Q.
The relatively taller front chamber (of both mine and others' K-variants) was intended primarily to keep front chamber tuning closer to that of a K15. Nobody has figured out how to make a shorter bass wave.
I'd suspect that the traditional K12 might subjectively have "more hit" because the front chamber has more volume and aperture area. Fiddling around with BP models shows than increasing volume also increase output and Q.
Let's talk about this again in a couple of months, when temperatures hit -30°C at night over here...
IG
Here is a Karlsonator with the Altec 416 scaled to 15/12 in both height and width:
With the width scaled to 18/12:
Now with both the height and width scaled to 18/12:
It seems that this driver has a very pro audio behavior of high efficiency with some reduced bass extension. It's a rather big cabinet though to achieve bass extension. The sims are for walls far away with mic at 1m.
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