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[Ivan Beaver]

I believe I have a drawing that I made of the Maryland Sound 1/2 clams that I had.   I will see if I can dig it up.  These were the concert versions.

[Iain_Macdonald]

Hi,

OK, glad I was wrong about the vent.

But I am still thinking that the analysis of the Tube is going to be different to that of the Khyboe(Clam).

Acoustic - Well well... I seem to remember them producing a motor driven sub. It never made it to the UK. When was/is this  115BK produced. The Leech product had a huge vent, the width of the cabinet.

Fred Walecki at Westwood Music LA used to build Karlson cabs for bass players. Fred told me that his cabs were a direct copy of the original. Nicely made and very solid.

Iain

[Tom Danley]

Hi Iain, Freddyi, all

I would agree the tube and “box” version are different.
In Freddyi’s post of Karlson’s patents, I see he played with antenna’s too.
This makes me sure that was the direction he was thinking as I have seen a balanced antenna which made me think, huh, a Karlson.

There are some amazing parallels between radio waves and sound but also some major differences.
For example, with an antenna, one reaches the radiation impedance of space with a wire a quarter wavelength long perpendicular to a ground plane (a mirror image). One can couple into that space at about 4X the impedance with a balanced (0 and 180 degrees) antenna made of two quarter wave lengths (half wave length overall).
For sound, that same “flat part” of the radiation curve is a function of area not conductor separation. .

Where a horn I think is a variable resonator (above the low cutoff  frequency) and like an electrical tank circuit can transform impedance’s from one end to the other, I do not see that in the box version of the Karlson, at least at low frequencies.
My guess would be that it is an acoustic low pass filter, which may have gain at the higher end of its response.  
A danger in drawing a conclusion from “close up” measurements is that when one changes the size of the radiation aperture, one can see differences in the sound level near field that are not related to acoustic power and would not show up at say 10 meters.
My hunch would be that if one measured the “box” version at 10 Meters, one would not find the “slot” increases the LF acoustic power (over some other shape), none of the dimensions are like what is needed down low.  
On the other hand, like any acoustic low pass filter, it will lower the distortion of the drivers output where it is rolling off.
Also, unlike any simple port used to make a low pass filter , one does not see organ pipe resonance’s, rather internal box modes mostly (it looks like) up high.

The Tube on the other hand is acoustically large enough in some of it range to do something unique. Exactly what I’m not sure, I’ve never seen a sensitivity or polar information on them. If it were also a variable resonator, then it could also provide an impedance conversion like a normal horn.

I do know that there is nearly always “another way” to solve a given problem and in antenna theory, there are things that look reminiscent of a Karlson and the goal of them is to provide a constant impedance over a broad frequency range (Freddyi, that book turned up).
It does make one wonder.
I suppose the thing to do would be to figure out how to model something with few enough segments and small bandwidth to work.

Iain, in that earlier post about Ted N., our PA wasn’t that loud, we had about 800Watts of mostly Tube amplifiers.  We played with Ted after Journey to the center… but right before he got big the second time.  I was 20 at the time so to me he was a scary fellow, although his brother was similar looking but a normal guy to talk to.
I found a link to a photo of the speakers we had in the PA and Gary Gand had one of me working on one of those tube amps back then fwiw.

http://www.livesoundint.com/archives/2003/april/water.php

Acoustic did make a motor driven woofer briefly, a subtec 2.6 or something.
This was an attempt to make a Servodrive but by using a crank throw, added the cosine distortion such a mechanism imposes.
I was pleased with Servodrive motor system, man its hard to believe that was 20 some odd years ago now. It did allow T&S parameters which one couldn’t make with a VC driver though, a key to making the horn work.

An interesting comparison can be drawn between the most powerful Servodrive, the BT-7 with uses a servomotor driver and conventional horn and the originating subject of this thread, the TH-115, which uses a conventional driver but a new horn configuration called a Tapped horn.
Four TH-115’s and four BT-7’s have about the same sensitivity / efficiency, the BT-7 is rated at 400Wrms, the TH-115 @1000Wrms.  The 4 BT-7’s are flat to about 32Hz, the TH-115’s to about 35Hz.  The Th-115’s, because of the different horn are about half the weight, cubic volume and cost.
Like I said to an old Boss, “there is nearly always a way to go around, under, over or bore through a technical problem”.   I think that is what Mr. Karlson was thinking too.
Anyway, the Karlson is a curious acoustic device, a better understanding and refinement of the various dimensions and shape could I think lead to something new also.
Best Regards,

Tom Danley

Danley Sound Labs

[Freddy Ireson]

re:Acoustic Control 115BK - had large vent ~3" high by 9" wide - IIRC Z-minimum with EV15L is ~56Hz so there's probably some pipe action besides added mass-load on vent from coupler.

a description of "Westwood" bass-guitar bin was very close so will assume 115BK is very close in size and innards if not "exact" to Zintz/Leech KHYBOE(?)

here's an ~half-space (my yard drops/slides off about 8ft from mic - lol)
for the 115BK with EV15L - it must not have any more than 2cu.ft. rear chamber

http://home.earthlink.net/~buddhaboy2/AKTILT.jpg

a PV FH1 in the same spot would look like

http://home.earthlink.net/~buddhaboy2/FH.jpg

Freddy

[Freddy Ireson]

Hi Tom (whoa - great pix!), Iain, Phil , guys (hey Ivan - U find  half-clam sketch?)

re: distance and plots here's an 8cu.ft K-box about like K15 but missing shelf refinements and loaded with a 0.25qts / 103g mms Eminence 18 vs UCS1 at 44ft distance. had K tuned ~42Hz z-minimum with two 4"ID x 4.5" long vents on its 1st reflector panel.  each cabinet was in same spot against corner of house and mic not moved:

http://home.earthlink.net/~buddhaboy2/44F.jpg

34Hz low level sine K vs UCS1 - 15dB more H3 on the pipehorn:
http://home.earthlink.net/~buddhaboy2/34hz.jpg

30vrms 50hz for K-box - careful not to smoke that coil!
http://home.earthlink.net/~buddhaboy2/30vrms.jpg

Rough side-view sketch of that 8cu.ft. k-coupler - its vents are 4.5"
holes on the 1st reflector panel. one board and an upper piece would probably be as good for midbass work. It started as a 15" coupler but got bored and took jigsaw to it to see what it would do with 18"
http://home.earthlink.net/~buddhaboy2/8cu.jpg

Another arrangement within 7.4cu.ft. which might work could be like so
(woofer is same Eminence 18" used in 8cu.ft. coupler above)
http://img358.imageshack.us/img358/4287/ha18capwjpg1co.jpg

This mod with extra cavity and a handful of polyfill produced the following 2M plots (rear chamber volume ~80l)
http://img408.imageshack.us/img408/7889/2mwebjpg4rx.jpg

whether sine testing showing high H3 has significant meaning vs "tone" - dunno

wideband, the original 1951-52 Karlson is probably tighter on than my box above - (15 vs 18 plus lowpass choke)

I'd normally tune this k a bit higher for a riper upper bass and nice shockwave effect. also like it as took one sheet of cheap plywood and weighs about 70lb loaded vs nearly double for the Unity.

The UCS1 had lots more 3rd harmonic than this k-box below 50.  UCS1 also has a higher Z-in - think around 10 ohms minimum- -neither are any good in my house for 32Hz -haha

John Karlson musta had good relations with Robert Moses as K15 (probably with EV 15RTX) was used in several exhibits at the 1964-65 World's Fair including Ford (with Disney Animatronics) GE and other exhibits.  a reliable source says Karlson did a rocket mic-speaker install for Moses and in abtract way reflected the twin-towers project.

FWIW in the legend of Karlson its said that loading below cutoff is one feature:

snippet from Dave Young's post:

I have built and used various Karlson couplers for PA since 1983.
There have been 15" and 18" woofers in 2'x2'x3' Karlsons of my own design.

"-For a while, I used X-15's for midrange with very
drastic equalization. I have used the Tube on top of a 12" Altec
for small jobs. I have also made a 2" Tube coupled to a Renkus-
Heinz 3300-8 for outdoor use. There are also some 12" coaxials in
use with a K-coupler for the highs.

As a low frequency cabinet, the Karlson is usable to 35hz with
low harmonic distortion.

Like any enclosure that depends on porting to augment the bass output, Theile-Small parameters have to be taken into consideration. I have yet to measure anything of comparitive size
that came close.

They get ugly above 175 hz. and require a crossover set from 100-150 hz.

The key to its low freq. performance is the coupled front chamber.

The increased air pressure loads the cone and dampens it.

A front loaded woofer and a horn loaded woofer operating below cutoff doesn't have that
advantage.

Twice I've measured the 3rd harmonic of 40hz(120 hz) louder than the fundamental with 100 watts
feeding the speaker.

The Peavey FH-1 and a Yorkville 2-18 with RCF's. When the 1504-4
Black Widow was tested in a 12 cu. ft. Karlson, the 3rd harmonic
distortion went from 103% to 8%. I didn't have the Yorkville long
enough to switch speakers."

***********

Carl says mass loading changes T-S parameters and evaluates up to 5 sets of wings (whew) - by his critera a Karlson bass coupler would not have a large rear chamber.

if feel up to it -  do some plots of Transylvania Tube in 15 degree increments at several heights.

re:K-Tubes - x15's tube imo has a significant ammount of energy propogated perpendicular to its long axis so theres a fairly high and even vertical window.  

Too Tall mentioned the Transylvania tube (which normally has slot "down" and tube angled up ~30 degrees) not having high vertical dipsersion - not sure - up close didn't seem to have much anything happening right above its structure- maybe it can be aimed towards the rear of an audience to good effect - straight down the tube would be imo where the highest HF goes (from listening to tape-hiss components)

Here's an indoors plot of a x15 copy with mic going up to overhead and perpendicular to the waveguide (loaded IIRC w. old PV 22A) the 1.875"ID tube on this Karlson x15 is mounted on its first reflector panel and aimed down 12 degrees from being parallel with the floor. (12 degrees subtracted from a nominal 35 degrees give the 23 degree baffle tilt)

http://home.earthlink.net/~buddhaboy2/X15/Perp.jpg

Here's same coupler/tube 85 to almost 90 degrees off horizontal axis in-room - that's the mic's position - lol

http://home.earthlink.net/~buddhaboy2/X15/Horz.jpg

like to get rid of that 2K2 notch - maybe wasn't as deep with 806a(?) was it from a diameter transition of a 1" OD 30 degree slice pre-waveguide to 1.875" ID tube?  

Karlson presented two circuit models for the coupler in 1952 Audio Engineering article - separate circuit for LF.

what type of Z tranformer (if any) is an Ultra-Fidelity type Karlson? - some couplers seem to have high outputs with good cone control.  there could be BP action - but is there more?

maybe they're 100% bunk - but can/or seem do some "stuff"/ give illusion - I like the vortex gun type effect on kickdrums

Best wishes to all
Freddy

ps - one more thing - here's plans for 18" 5181 10.3 cubic feet Karlson cabinet by Cetec-Gauss. note - dimensions on page one include carpet. look at page 3 before building - lol (also double check that wing radius to see if correct)

http://home.earthlink.net/~buddhaboy2/GK

can some K-couplers be made to work stronger within their passband for a given bulk by allocating more air-mass load from front chamber so rear chamber isn't quite as large as 5181's approach? - thoughts?

[Iain_Macdonald]

Tom,

Yes I have heard the Servo product. For a short time,(and not short enough for me) I was part of the company that imported Servo product to the UK, 1988 approx. We had 12 x SDL 5. They were sold to a "rave company", and the last I heard they were still working.

Now I know why you moved south.

http://www.tnugent.com/

Iain

[Freddy Ireson]

Hey Iain, Tom and guys - IIRC there were other Karlson-types in the 1970's -  around 1971 I saw and heard "something on a pole" outdoors in a small venue which wasn't standard Ultra-Fidelity type nor klam-projector 'ala JEK AP and JEK's Oliver-Projects - wonder what  those were and what called? - didn't look DIY but could have been.

Freddy

[Phil Pope]

Anyone got to grips with the Poppe paper?

http://home.planet.nl/~ulfman/files/poppe_kcoupler.pdf

I managed to struggle through the Marshal Leach horn paper but the Poppe paper is a bit beyond me.  

Got some spare Ciare 12.00SW drivers sitting around so I am going to try a 1.8m Klam and see how it goes. Hoping to get down to around 50Hz.

Anyone know how LF cutoff is related to length and cross-section area at both ends? What sort of T/S parameters are suitable for a Klam design? Is rear chamber volume important?

Phil

[Freddy Ireson]

Hey Phil - you'll have to contact and engage Carl into some practical directions as to what will happen as he's built a number of AP-style klams.  I'd think be some coupled-cabity type action to  account for part of its response.  Ciare should be nice driver.

Best!
Freddy

[Phil Pope]

Freddy

you mention Carl in one of your other posts but where would I find him?

cheers
Phil