Tell me about Karlson speakers

[gadget73]

I rescued this lovely beastie from the burn pile at Kutztown. This is an original Karlson 15" speaker cabinet in fairly decent shape. Some of the veneer is coming loose, but it can be re-glued. This uses formica veneer, so its not all that fragile. Sticker is all but gone, no grille cloth and its of course empty. The box is solid though and very fixable.

Question is whether or not its worth fixing and finding or building a mate. How does one run these, full range or do they usually go with an external horn tweeter or something to fill in the top end? I see lots of plans online, just wondering if it makes more sense to try and seek out an original mate or just put together my own. Looks to be basically all plywood construction, nothing that can't be duplicated without excessive trouble.

Also, aren't these supposed to have a back panel as well?

 

[elitopus]

I voted for finding an original mate. If I had two choices I would also include build a mate as an option.
I read a thread where a few people were saying the Altec 604/605 duplex sounded good in those cabs.
I'm pretty sure its supposed to have a back panel

 

[gslikker]

I would put it in the garbage (I built a pair 40 years ago.....using Philips AD12100, they were LOUD). Yes, they have a back panel

 

[knockbill]

Well, I have no dog in this fight,,, maybe like the last poster suggested, you may find a mate in the garbage!!!! However, if it were me, I'd find a good pic of the back, and replace the missing panel.... Then you will be in a position to try replacement speakers at will and see how you like it before spending time to restore it... I'm sure its worth that much attention...

 

[phil-g]

would a karlson cabinet be considered a tapped horn?

 

[bshorey]

I'd go for choice #4 - load it up with a single driver and use it as a subwoofer.

I had a single one many years ago. I don't remember being impressed with it very much as a full range, but it did deliver decent enough bass, and might be useful in a situation where you need some bass reinforcement along a wall.

bs

 

[AFP1]

Check over on thhe Audio Asylum, a member there, Freddyi, has been posting about Karsons for many years. Tons of information, he's always willing to help.

 

[Joe Roberts]

I ran across many Karlsons while scavenging back in the day. Many were super well made DIY projects with great speakers in them. 604s, WE 728Bs etc.

I had one built by a Raytheon engineer in the 50s that was two layers of 1" plywood with sand in-between, and a WE728B. It took me a day to get the 728 out!

I never had a case where the speaker sounded better in a Karlson than in a reflex or sealed box. Too much refection and diffraction. Good bass but not good full range.

This one looks DIY, in which case there is no mate.

In my mind Karlson is a boom box.. If we were talking about a nice pr of factory or super DIY cabs, there would be some historical value perhaps.
Otherwise I'd throw it on the scrap heap myself, but it should be fun to try one out.

 

[westend]

Well, you know you've got to load a woofer in there and have a listen. This is how I learned a bit about boxes, load them up and try.
Freddyi has been experimenting with Karlson boxes for years. He posted many times on the Full Range Driver Forum about loading the cabs.
Some are using this cabinet and like the results and some have tried it with mediocre results. Fitting a correct driver in the box is most of the work. I cant advise on which one since I don't have hands on experience with it. I've seen where at least one user installed or incorporated a tweeter with the enclosure.

Good luck with it, should be a lot of fun!

 

[Poultrygeist]

I'd leave the back open and add a high Q woofer for some nice bass augmentation.

 

[chazvintage]

I have been using a EV horn loaded cab and a Karlson cabs set up with rebadged goodmans =allied hc 615 drivers and they sound very nice to me. A plus for you is the formica is an excellent insulation for cabs , I see your missing the the damping material on the bottom.

 

[gadget73]

I'd go for choice #4 - load it up with a single driver and use it as a subwoofer.

That is a good thought if they do solid bass. Saves the trouble of finding or building a twin too.

Maybe I'll make a back and stab a woofer in there. I've got a 15" Magnavox full range hanging around here I can try just to get an idea what it might sound like. For more bass-like duty I could steal one of the 15" woofers out of the crappy Kenwood garage stereo speakers. They make boom at least. If it becomes a sub, I suspect it will not keep that driver. I have an un-finished room on the front of the house that I wouldn't mind turning into a theatre/stereo room eventually, and having a cool looking old speaker cabinet that serves subwoofer duty wouldn't upset me any.

This one looks DIY, in which case there is no mate.

Pretty sure this one is factory. The sticker is almost completely gone, but I can just make out the Karlson script. Its the middle picture, and it really is that hard to make out in person. Just basically the outline where something was, and I can sort of make out the letters.

 

[Poultrygeist]

Pulled these 16 inchers from a pair of Sansui Kabuki's left on the curb. I was surprised by the nice bass in open baffles with a fixed low pass.

 

[knockbill]

That's your best bet,, no sense going nuts with it, at least until you hear it!! May want to try the Maggy speaker with the back on and/or off... those speakers were used in open back cabinets/consoles... no?? You can also make an adapter ring to try different 12" speakers that you may still have...

 

[Joe Roberts]

Pretty sure this one is factory. The sticker is almost completely gone, but I can just make out the Karlson script.

I never saw one with the wide picture frame molding around the outside and that aspect looks DIY to me. It appears that a grill cloth was added and the frame holds it in place. Looks like hardware store molding.

Let's face it, a naked Karlson could be considered to look pretty strange for the conservative mid 50s living room, although I can dig it personally.

Perhaps it is a kit model. They made em. I read an interview where it was stated they had six factories around the country cranking out genuine Karlsons at the peak of popularity.

But anything is possible and I am not a Karlson specialist. There are Karlson experts out there though.

 

[2020]

I own a couple of Karlsons loaded with Philips full range drivers. I bought them for $5.00, and figured I'd throw away the drivers pretty much immediately and then pitch the cabinets after I played with them a little.

I was VERY surprised at how good they sounded and kept them. I have been experimenting with several mid/tweeters, and think they sound very musical. They do not seem to me to have a lot of audiophile mojo that is puffed up in a lot of magazines, but they are very pleasing to listen to. Just my humble opinion.

Regarding the subwoofer idea, I remember reading in an ad from the '60s about a bass guitarist who used Karlsons for his stage speakers.

I would keep an eye out for another one if it were me.

 

[freddyi]

might be factory (?) - the glue blocks are triangular like factory Karlson cabinets.
They can sound very nice with weak motor speakers with good midrange, but need pretty strong motors to exhibit their full potential. Loudspeakersplus has a sale on 15 inch P-audio coax for $99.95 including the BMD440 compression driver. I don't know how that coax woofer sounds but should be ok they regularly sold for $269 each some years back. Be sure to brace the back panel - two vertical on-edge stripes of plywood ~1.5" high could help. Even a single strut from the back panel to the center rear shelf will reduce boominess caused by panel flexure. Also, you can use 3/4" dowel struts from the front shelf edge to the wings as extra bracing.

for some speakers, you can tweak things by experimenting with the rear shelf lowpass gap

If you just have a good woofer, then instead of putting a horn on top, you can make a "K-tube" with a compression driver - make it approximately the size of the old Transylvania Sound Company's "THE TUBE" 5.3" long from tip to driver mount, a half ellipse profile slot and ~1/8" starting gap.

GregB came up with a K-variant he calls the "Karlsonator" - the driver sits in an offset line - tuned lower than traditional K - goes lower - probably less punch - there's several threads on that at Diyaudio

here's my 18 inch K-coupler with an EVM18B and internal slotted pipe per 1966 "X15" Karlson system playing some light music - LOL - not bad for a generic Xover and components - its just a bit larger in bulk than K15

 

[Pio1980]

I ran across many Karlsons while scavenging back in the day. Many were super well made DIY projects with great speakers in them. 604s, WE 728Bs etc.

I had one built by a Raytheon engineer in the 50s that was two layers of 1" plywood with sand in-between, and a WE728B. It took me a day to get the 728 out!

I never had a case where the speaker sounded better in a Karlson than in a reflex or sealed box. Too much refection and diffraction. Good bass but not good full range.

This one looks DIY, in which case there is no mate.

In my mind Karlson is a boom box.. If we were talking about a nice pr of factory or super DIY cabs, there would be some historical value perhaps.
Otherwise I'd throw it on the scrap heap myself, but it should be fun to try one out.

This is a design that never made sense to me, seems a waste of time, wood, and drivers.

 

[Joe Roberts]

Wayne Green, who was the sales manager for Karlson, admitted in print in an editorial in his ham magazine 73, somewhat jokingly perhaps, that they never actually figured out how it works!

The notion is based on techniques for broadbanding microwave slot antennas. Since the slot width is the tuning mechanism, so to speak, by having a tapered slot, you cover a lot of possibilities.

I am not certain that the metaphor exactly transfer to a front loading doodad in front of a speaker, any speaker that will fit the cutout,-- coax, woofer, full range, whatever. It seems like magic.

 

[freddyi]

fwiw, I think the bass is pretty "adept" excellent on plucked and bowed bass viola, good, vivid midrange with speakers like what were used in their day (Knight HC615 was the same as EV15TRX used at the 1964-65 World's Fair) K15 when loaded with a weak motor Beta15cx, had 1/10 the sidebands (modulation distortion) of a reflex the size of its back chamber. I've measured K15 size K-coupler to have 20dB less harmonic distortion than some horns. The guys at Cogent like the Karlson. I like the little K12 but am not fond of the distributed slit port which will distort if fed with sin wave near Fb. A single 12 square inch port would be better. Of course, Karlson cabinets were sold usually by themselves in an age of mix and match and some lower priced speakers had weaker motors so could use the damping of the constrictive/ resistive vent.