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Old 14th February 2010, 09:49 PM   #21
freddi is offline freddi  United States
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doesn't look like a horn - ~15lb built of 3/4" plywood - would play ~10dB louder than in this demo (might cook voice coil)
YouTube - karlson projector speaker
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Old 15th February 2010, 07:59 AM   #22
max axe is offline max axe  United States
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All right.....whats the scoop on the Karlson impedance match invention?
I am going to have to leave it up to you who have knowledge.

Can you increase the effective acoustic diameter by scalloping the edge of a horn? It would take me too much time I think to try and search and digest everything when the knowledge lurks somewhere in the minds of diyAudio members.

I like the design direction of bjornos bass bazookas coupled with a horn. Im on the verge of ordering more 2 inch drivers to pursue the unity as per the suggestion. If the Karlson concept could reduce the mid horn diameter at the expense of more length, that would be perfect. In an ideal portable PA system, the horns could fit just inside the bass bazookas although as the design is, they are too narrow in diameter. Small point. With some minimal legs, the bass towers could double as stands also for the horn. It would be really cool...

Isnt there an iron law about size vs efficiency? I wonder how bjornos bass tubes compare. In fact what is the type of speaker with the greatest efficiency per volume everyone should know that I guess? hmmmm electrostatic flat panels maybe...being theoretically two dimensional....

Max
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Old 15th February 2010, 02:36 PM   #23
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Yep, it's proportional to the cutoff frequency (Fb) cubed times box volume (net Vb), divided by the electrical quality factor (Qes). The proportionality factor is different for different designs, sealed/reflex/whatever. This is the best efficiency possible within the laws of physics, naturally there are ways to get less efficiency for the same box which is what most actual speaker alignments wind up being as the trade-off to get a wide band-width (BW).

GM
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Old 15th February 2010, 08:59 PM   #24
max axe is offline max axe  United States
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obliquely truncated conical horn, standard model for mammalian pinna. Cant be all bad.

did anyone have success with a midrange karlson looking like his high frequency unit?
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Old 15th February 2010, 09:59 PM   #25
freddi is offline freddi  United States
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the high frequency Karlson unit was the 7" long slotted tube used in his 1965 2-way X15 system - - I'm not sure how good of a midrange one could make but Robert Reams (Neural Audio) made a double slotted "Clothespin" tube which I believe was driven by an EV12L


Karlson's 1961 letter to Carl Martin Poppe explaining the asymmetric projector
pattern
http://home.earthlink.net/~buddhaboy2/Let61.pdf
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Old 16th February 2010, 08:09 PM   #26
max axe is offline max axe  United States
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SCIENCE!
Thomas Dolby

I guess I begin the long process....
"we believe the cause of death was multiple iterations"

Hornresp! what a fantastic program! He blinded me...with SCIENCE

I expected the size of bjorno's much appreciated Unity design using 4 peerless 2 inch to have a mouth of 18 inches probably. But I started to play with his template in Hornresp and it appears that the diam is more like 7 inches, which is what the concept calls for, size wise. I started to play with parameters, and it appears that the gain is due to the 6 db half space radiation and 6 db from using four drivers, while the horn serves to modify only a few db in the 3k hz and up region. Actually, it confuses me a little that if I start with full space radiation as the baseline, then add baffle area, it seems to reduce the high frequency as opposed to boosting..... Maybe its due to how the measurement is specified in the field.....

So I could be entirely wrong in all of the above thinking, but if its about right, it makes me wonder about the value of the horn,with its driver mounting difficulties when the drivers themselves should have the same spl at the low end, and full range on up....
Thats to say that simply mounting the four drivers on a flat baffle at the horn mouth and using the horn as a labyrinth, the low freq spl looks the same, and the high end might be smoother..?

Now using a much longer horn, and the same mouth area, its possible to get about a 10 db boost but with periodic peaks of about 6 db. I wonder, in this application, how bad that would sound. Are the peaks due to reflections and phase interaction? Is it worth persuing a sub optimum mouth size horn in order to achieve a usable response down to 200 Hz?

Max
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Old 16th February 2010, 08:20 PM   #27
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What Unity design? It can't be simmed in HR.

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Old 16th February 2010, 09:52 PM   #28
max axe is offline max axe  United States
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uh oh. My mistake. Maybe I should have said offset driver location. Im not at all familiar with these things yet. Its just the bjorno placed a picture of a Unity indicating what could be possible and this threw me off...I guess the thing with the unity is that the mid drivers can be placed to load the horn at the right flare and yet maintain phase with the compression driver at the throat....or something like that, and HR doesnt model two different simultaneous driver locations. In that case I suppose you cant tell at all what mid band response you would end up without the rear driver in the mix....

thank you,
max

Max

Last edited by max axe; 16th February 2010 at 09:57 PM.
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Old 17th February 2010, 05:23 AM   #29
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OK, just wanted to be clear on what you were referring to. Anyway, no way to use a Unity concept to hide your actual instrument in, so not sure why you're interested in it.

GM
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Old 17th February 2010, 06:56 PM   #30
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Hi there MaxAxe: I would like to prpose a diffrent solution: a vented enclosure using 2 drivers, and for apperance ( audance reaction ) a horn section coupled to the enclosure vent. Some sound will exit the horn, near your ear and the enclosure will be housed in a form of a back pack with the drivers sound exiting from each side. This concept is the result of an experimental enclosure I constructed a couple years ago, and the parts are still gathering saw dust in the shop. If you are interested, you can contact me at ddroke@msn.com ...regards, Michael
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