Karlson dipole sub - would it do any "good"?

[freddi]

Icebear gave a Karlson-dipole box sub a whirl a few years back - it had two drivers and rear slot aperture was inverted - besides looking different and potentially exhibiting a cavity peak, could the approach be useful?

[Ron E]

A sudden flash of inspiration. Wouldn't it look kool to have a 2 driver dipole karlson box.

If you don't like the look of the woofer motor, you could hide it behind the skinny portion. IF you do, you put it in the open portion. Or you could hide them both behind grille cloth....

enjoy.

[moray james]

for the phase of the two drivers? I agree I like the look.

[Ron E]

I was thinking one mounted with cone facing forward and one with cone facing back, wired so they move the same direction. Instead of Ripoles, freddi could call these Kipoles BTW, that's my first Sketchup model ever, done in ~15minutes. Would have taken less time, but I am used to AutoCAD.

[moray james]

So the drivers are mounted such that their magnets are both inside of the cabinet and from the front or back side of the cabinet if you look inbetween the tapers all you will see is cone, is that correct?
Are the drivers in phase with each other? Meaning that a positive impulse causes both cones to move out of the cabinet at the same time? That being the case we have a Bipole configuration.
Or are the drivers wired so that as one cone moves into the cabinet the other moves out of the cabinet. Sorry but I always get myself confused about this sort of thing. I think that I have a disconnect between what I read/think and what I visualize which probably has something to do with my dyslexia. Thanks for taking the time to make your thoughts clear to me

[Dag Johansen]

Here in Norway we have an loudspeaker-manufacturer wich makes a sort of dipole like that:
Its sounds nice with all the benefits of a dipole construction, but the midrange/tweeter suffer from the positioning inside the wraping.

[Ron E]

Originally posted by moray james
So the drivers are mounted such that their magnets are both inside of the cabinet and from the front or back side of the cabinet if you look inbetween the tapers all you will see is cone, is that correct?
Are the drivers in phase with each other? Meaning that a positive impulse causes both cones to move out of the cabinet at the same time? That being the case we have a Bipole configuration.
Or are the drivers wired so that as one cone moves into the cabinet the other moves out of the cabinet. Sorry but I always get myself confused about this sort of thing. I think that I have a disconnect between what I read/think and what I visualize which probably has something to do with my dyslexia. Thanks for taking the time to make your thoughts clear to me

There is a K-coupler on each side, and in the middle of the box is a baffle with two holes cut in it. You wire the woofers out of phase and mount them so that in the diagram one woofer is facing you and one is facing the rear. When a positive pulse is applied, both woofers move towards you. Basically an H-Frame Dipole with couplers on each side. The front and back sides of the woofers are just open to the couplers, no enclosure other than to hold the baffle and front and rear couplers.

I don't think the couplers would do much other than perhaps mass-load the diaphragms a bit. The concept looks kinda kool, and I don't think the couplers will hurt anything in a subwoofer application.

[Rudolf]

Some thoughts about that double Karlson H frame (Kipole) Ron E showed above:

1. Looking at the large opening at the top of the frame it should behave like a conventional H frame with its quarter wavelength resonance. Looking at the almost non-existent opening at the bottom it should behave like a closed box with a half wavelength resonance inside.
So I would expect a somewhat "smeared" resonance peak, mainly at quarter wavelength but broadened to higher frequencies.

You could get a similar "smearing" of the resonance by rotating the driver baffle 45° in a conventional H frame. Whether horizontal or vertical 45° doesn´t matter.

2. The Karlson slot aperture closes the H frame opening to some degree. This is what a Ripole does too. So you can expect some mass loading of the driver (probably resulting in a lower Fs) and a pronounced quarter wavelength resonance peak (which will be attenuated by the slot aperture as discussed in 1.

Since we are talking about subwoofer frequencies, the special exponential(?) aperture of the slot doesn´t matter at all.