Karlson Cabinets

[dlhughes]

Kinda sick, I know....but I'm obsessed with Karlson boxes!

I had one at one time, custom-built by a friend who ran a sound company, and it really made some big noise without a lot of power input. I didn't really have need of such a monster at the time, so I sold it. Bad Move!

I was wondering if any of the rest of you use or have used a Karlson cabinet. For those who don't know what that is, it's one of those very weird-looking things with the driver set back from the front of the cab on a slightly inclined baffle, and having an 'exponential' flaring slot opening in the front panel. Acoustic Control used to make one years ago, actually, for bass cabs.

Attached (I think) is a photo of someone's bass rig that I snatched off some Web forum or other. This is the type cabinet I'm talking about.

Does anyone here use on, or have you used one, and if so, what are your likes & dislikes about it?

[abarson]

I played through an Acoustic BC2 combo a long time ago, and back then it was the best sounding, loudest combo I'd encountered. I was tempted to buy one recently on Bay Area Craigslist, but I just don't want to haul the weight around.
I've toyed with building a Karlson cab with a Deltalite II 2512, but have too many projects right now. What's the story on the one in your photo?

[ahc]

Back in the stoneage I had a pair of those loaded with JBL D-140F's. I powered them with an Ampeg BT-140. The Karlsons were heavy, but put out a bunch of bass. The BT-140 was probably the worst idea Ampeg ever had. I kept the Karlsons around for years and a couple of bands I was in used them for PA bottoms... until an idiot trombone player/soundman/bandleader blew them both out. TWICE. They were reconed (again) and eventually I sold the empty cabs. Later sold the D-140's, which might not have been such a good idea. One guitarist used to laugh at the " Karlson Couplers" every time we set up. Why??? He was a guitar player, that's reason enough why

Al

[B String]

I owned one for a while in the 80's. It was a little problematic for me. It never seemed loud enough on stage for me to hear well, but it was killing the soundman out front. The full sound of the box didn't form until it was way out in front of the stage. If you need a good "long throw" box, this is it. If you need to hear yourself right in front of the box, it might not be the best design choice.

[dmusic148]

Originally Posted by B String

...The full sound of the box didn't form until it was way out in front of the stage. If you need a good "long throw" box, this is it.

That doesn't actually happen. It's all about midrange directionality. Being close to it, you couldn't hear the mids because they were aimed at your knees. Sound doesn't 'develop' with distance. No such thing as 'throw.'

[billfitzmaurice]

Originally Posted by B String

I owned one for a while in the 80's. It was a little problematic for me. It never seemed loud enough on stage for me to hear well, but it was killing the soundman out front. The full sound of the box didn't form until it was way out in front of the stage. If you need a good "long throw" box, this is it. If you need to hear yourself right in front of the box, it might not be the best design choice.

There's no such thing as a long throw woofer, or 'wave formation'. The Karlson is a bandpass box, which means it has poor mids, much like Acoustic and Ampeg folded horns of the same era. It thus suffered from the same lack of intelligibility on stage, as explained here:
http://billfitzmaurice.info/forum/vi...php?f=10&t=999

Like all bandpass cabs the Karlson won't work well on it's own, it must be paired with a midrange driver. The woofer section can be modeled as a series tuned bandpass.

[B String]

Originally Posted by billfitzmaurice

There's no such thing as a long throw woofer, or 'wave formation'. The Karlson is a bandpass box, which means it has poor mids, much like Acoustic and Ampeg folded horns of the same era. It thus suffered from the same lack of intelligibility on stage, as explained here:
http://billfitzmaurice.info/forum/vi...php?f=10&t=999

Like all bandpass cabs the Karlson won't work well on it's own, it must be paired with a midrange driver. The woofer section can be modeled as a series tuned bandpass.

Well being a user and not a maker, I guess I need a little education.

What is the technical explanation or term for when it sounds huge and bassy when you stand three feet in front of the speaker box, thinner and less bass when you stand twelve feet on front of the box, and big again when you're twenty feet away? These are approximate distances, but the phenomenon is real. (I think....Damn drugs!)

[Mr. Foxen]

Originally Posted by B String

Well being a user and not a maker, I guess I need a little education.

What is the technical explanation or term for when it sounds huge and bassy when you stand three feet in front of the speaker box, thinner and less bass when you stand twelve feet on front of the box, and big again when you're twenty feet away? These are approximate distances, but the phenomenon is real. (I think....Damn drugs!)

Boundary cancellation. Probably from the ceiling, shows if you get those distances proportional to the ceiling height in some way.

[lbwdog]

Didn't Karlson make some cabs that were somehow filled with sand, or did I dream that?

[billfitzmaurice]

Originally Posted by B String

What is the technical explanation or term for when it sounds huge and bassy when you stand three feet in front of the speaker box, thinner and less bass when you stand twelve feet on front of the box, and big again when you're twenty feet away?

It's called Boundary Effects.

Didn't Karlson make some cabs that were somehow filled with sand, or did I dream that?

That was Wharfedale; they made hi-fi cabs from two sheets of plywood with up to an inch of sand in between them. They were non-resonant, to say the least. Immovable too.

[dmusic148]

Originally Posted by Mr. Foxen

Boundary cancellation. Probably from the ceiling, shows if you get those distances proportional to the ceiling height in some way.

....and boundary reinforcement, as well. Gets loud at twenty feet or so? If it's a forty foot room, you're right at the center, and so you hear the stage sound AND the far wall at the same time.

[billfitzmaurice]

Originally Posted by dmusic148

....and boundary reinforcement, as well. Gets loud at twenty feet or so? If it's a forty foot room, you're right at the center, and so you hear the stage sound AND the far wall at the same time.

You wouldn't get a major boundary reinforcement there. That will happen fully where the distance from the speaker to the listener is twice the distance of the listener to the rear wall, so in this case about 26 feet back. The reinforced frequency would be where 26 feet is 1 wavelength, 43 Hz. The same spot would have a null 1 octave down, at 21.5Hz. There are websites completely devoted to boundary effects, which are really a problem in home theater, as the rooms tend to be way smaller than 1 wavelength.

[dmusic148]

^ I stand corrected. I should have said 'out in the room.' This explains why we sometimes hear that people 'near the back' are 'getting killed' by the bass.

[B String]

Originally Posted by billfitzmaurice

You wouldn't get a major boundary reinforcement there. That will happen fully where the distance from the speaker to the listener is twice the distance of the listener to the rear wall, so in this case about 26 feet back. The reinforced frequency would be where 26 feet is 1 wavelength, 43 Hz. The same spot would have a null 1 octave down, at 21.5Hz. There are websites completely devoted to boundary effects, which are really a problem in home theater, as the rooms tend to be way smaller than 1 wavelength.

Ouch...I have a headache. No really, I appreciate the information, I just don't understand it all.
So are you saying that it makes no difference about box style or shape. That whole "this box sounds better than that box off the stage" is all about the room, not the box. Example:

I had an Epifani UL210 for a while. On stage it had a ton of low end. (for a 2x10 box) The general consensus from TB's knowledgeable was that the UL210 didn't throw that low end into the room as well as other boxes.

Is there another reason that box would throw more or less lows into the room than other boxes, or is it always the room dimensions? I don't mean to ask stupid questions, I just want to know what I'm talking about.

[billfitzmaurice]

Originally Posted by dmusic148

This explains why we sometimes hear that people 'near the back' are 'getting killed' by the bass.

Two reasons. First, they're too far away to get cancellations from boundaries near the speakers. The second is if they're 1/2 wavelength from the rear wall they'll be in a reinforcement mode. From 100 to 40 Hz that's about 6 to 14 feet. But if they're 1/4 wavelength from the rear wall they'll be in a null mode. From 100 to 40 Hz that's 3 to 7 feet. And since those ranges overlap they can be getting a reinforcement at one frequency and a null an octave lower. It's really screwy near rear walls, and those who stay back there in hopes that it won't be as loud are often recipients of a rude introduction to the realities of acoustics.

The general consensus from TB's knowledgeable was that the UL210 didn't throw that low end into the room as well as other boxes.

Different cabs don't 'throw low end' any differently. Cabs either have a good low end or they don't.

[dmusic148]

Originally Posted by billfitzmaurice

Different cabs don't 'throw low end' any differently. Cabs either have a good low end or they don't.

I'll drink to that. There is a weird belief among some folks that bass can be 'thrown' or that it 'develops' at some distance from the cab. All nonsense. Noise gets quieter the farther you are from it's source, always, period. Simple physics. Pay more attention to Bill than to me though. I have a layman's grasp of this stuff whereas Bill is an actual engineer, and a damned good one.

[62bass]

After all that-getting back to the Karlson. I went to a rock concert back in the days of the Twist. Rather than explain that just Google The Twist.

There was an instrumental group on and their bassist had 2 Karlson cabs powered by a McIntosh power amp-probably about 100 watts. It was in a 2000 seat hockey arena that was packed. Best bass sound all night. Deep and thick and really supported the band. But remember-that was way back when and the guitarists were using small open backed combo amps and not too loud. These days those cabinets wouldn't cut it compared to some of the properly tuned ported cabs out now. Groups today are playing way louder than what was considered loud back then. The band that backed up Chubby Checker had a bassist using a 2x12 Fender Bassman. You could hear it but it had a thin and distorted sound.

I also heard a pair of Karlsons in a home sound system. Low powered tube hi-fi amp. Probably a Heathkit. It had a big bass sound and once again lacked mids. There were better than Karlson speaker cabs being made back then.

I like the look of the Karlson too but I'd be wasting my money building them when there are so many better designs out today that would be smaller and weigh less and sound much better. Like one of Bill's designs or a Fearful.

Speaking of strange design from back then-does anyone remember the RJ enclosure?

[BassmanPaul]

Originally Posted by billfitzmaurice

That was Wharfedale; they made hi-fi cabs from two sheets of plywood with up to an inch of sand in between them. They were non-resonant, to say the least. Immovable too.

My dad had one of those, the SFB3. A three way with, IIC, a twelve, a ten and a vertically firing tweeter. Coupled to a Leak system it's the amp I learned to play on. Thanks for the memory Bill.

Paul

[B String]

Originally Posted by billfitzmaurice

Two reasons. First, they're too far away to get cancellations from boundaries near the speakers. The second is if they're 1/2 wavelength from the rear wall they'll be in a reinforcement mode. From 100 to 40 Hz that's about 6 to 14 feet. But if they're 1/4 wavelength from the rear wall they'll be in a null mode. From 100 to 40 Hz that's 3 to 7 feet. And since those ranges overlap they can be getting a reinforcement at one frequency and a null an octave lower. It's really screwy near rear walls, and those who stay back there in hopes that it won't be as loud are often recipients of a rude introduction to the realities of acoustics.

Different cabs don't 'throw low end' any differently. Cabs either have a good low end or they don't.

Thanks for helping to end years of ignorance. Sometimes I feel like I wallow in it. I guess this makes many of my opinions here on TB tainted with a distinct lack of knowledge. oof..

[lbwdog]

Originally Posted by lbwdog

Didn't Karlson make some cabs that were somehow filled with sand?

Originally Posted by billfitzmaurice

It's called Boundary Effects.

That was Wharfedale; they made hi-fi cabs from two sheets of plywood with up to an inch of sand in between them. They were non-resonant, to say the least. Immovable too.

Somebody made a bass guitar cab in the early to mid seventies with sand, just can't remember who.....irrelevant anyway