Small coaxial Karlson-couplers

[freddi]

an eight to ten inch coupler with Eminence coaxial, might be fun. The 22.5" tall coupler below ran 30 degree tilt baffle, 12 degrees forward cant on the port board, and an extra piece (~3") at top angle set for highest and widest image. Rear chamber was ~ 1 cubic foot.

perhaps less depth from wings to baffle, less baffle angle and more height would have helped matters and reduced a half-space outdoors peak around 210Hz (?)

at any rate, this thing had a wild sound for its size with room filling "stuff", holographic depth and quite a bit of impact.

anyone here build small Karlson type? - if so , what worked well for you for aspect, tilt, etc.?

[Scottmoose]

No, but I'd like to, one day, out of interest. I still think the Karlson is fundamentally a good idea, but it's going to need someone like Martin King to take an interest in the physics before we're ever going to be able to optimise them properly without large amounts of ROT and trial & error. Which has put me off a bit: I don't have the time, the resources or the money to experiment in the physical domain -I prefer to do my major design work via a computer, and simply tweak / refine the details.

[freddi]

my take on couplers so far = mix of things. distortion can be very low - dynamics high - for their faults, I'll take K15 size (including 18K) over my Klipschorn, OB , etc with regards to getting a good drum tone. They intoduce a sensation of reverb where certain sounds such as strings plucked seem emphasized in body while vocal transients can be relatively undisturbed.

what does one do if a graph is like the following yet the wing change produces a large subjective change? (at least at 6-8 feet distance) - this is in-room with both traces about overlaying but I suspect outdoors plot might not show much either. This was a floor perspective. 3rd Z peak on this coupler came in around 195Hz. Adding a 20l right angle stub to the front pipe at top dropped that to ~135Hz.

did the larger gap simply introduce a better mix of whats happening in the upper half of the coupler? - it raised Fb by a couple of Hz which might not be easily offset by re-tuning the rear chamber in a "subjective-tone" manner

coupler was 21.25" wide, 16" deep, 23 degrees baffle, 10 degrees port board, two 4.5" by 4.5" vents and built to test 18" in compact setting. That wider wings gap was fun with a Smith horn on top and an 18"which sounded crappy midrange-wise in my 8 cubic foot RJ reflex. A subsequent taller coupler is a good player lower.

maybe Moray will add some observations and rules of thumb for fullrange K's (SP15B despite high qts sounded pretty good in middes with K15)


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