That sounds like a good wall hanging size. You will need to check if the driver height matches approx ear height depending on how high up you hanf it. Which driver were you thinking of?
You can find out some stuff on the old Job Ulfman website.
The Karlson Homepage
Googling "karlson speaker" for image results should also satisfy your curiosity.
There is indeed a lot of pressure in the front chamber especially at the very top of the aperture. Even 0.75" BB-ply wings have to be braced on anything larger than an 8" Karlson.
IG
IG,
Karlson aperture is very interacting and seems like it could be applied to a lot of concepts. Like a BIB... the purpose of the aperture does not depend on it not moving by several mm. It may be annoying but I don't think it affects sound as long as it doesn't rattle or buzz.
Karlson aperture is very interacting and seems like it could be applied to a lot of concepts. Like a BIB... the purpose of the aperture does not depend on it not moving by several mm. It may be annoying but I don't think it affects sound as long as it doesn't rattle or buzz.
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The Karlson aperture is generally used to gradually terminate a pipe, in order to avoid reflections. It works quite well, especially if you look at the impedance plot of the Transylvania Power Company "The Tube" HF waveguide, there are your two main peaks and almost no signs of reflections.
IG
IG
I thought about slowly terminating a transmission line using a narrow vent running along some percentage of the total line length many years ago. In early 2009 I experimented with foam-core prototypes using this idea around the same time U.S. Patent 8,351,630 was applied for. Then I heard about a guy named Karlson
The effect I noticed (and liked) was a lack of strong standing wave influence similar to an open baffle.
There are actually several patents around this basic concept.
The effect I noticed (and liked) was a lack of strong standing wave influence similar to an open baffle.There are actually several patents around this basic concept.
I thought about slowly terminating a transmission line using a narrow vent running along some percentage of the total line length many years ago. In early 2009 I experimented with foam-core prototypes using this idea around the same time U.S. Patent 8,351,630 was applied for. Then I heard about a guy named Karlson
There are actually several patents around this basic concept.
Yes, it works well and lots of patents around. John Karlson was most active during the 50ies. He referenced much older patents, such as Swinyard, Fulmer... There were a handful of off-shoot licencees in the 70ies - it's a bit of a mess trying to patch up this history together. There are a few modern implementations if you know where to look, both DIY and commercial.
IG
I have seen similar things done by drilling series of holes of increasing dia as edge of pipe gets closer. It is all about matching impedance of pipe and room air. In the optical domain, a series of thin films is used to make antireflection coatings on lenses and windows. So what would happen if I put a Karlson slot on the end of a BIB? It would probably really smooth out those bumps that are in the simulations and make it less boomy. Easy enough to try in foam core
I first used this idea to treat the "back wave", a kind of transmission line. I never actually took any sound field pressure readings but merely cutting a slot (even a narrow one) seemed to eliminate the bass. Also, the cross-sectional area was tapered gradually along the length.
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Thanks for pointing out the iBIBk thread Planet10. I scanned through it quickly and it seems that it is still at trial and error stage? Start small and expand as needed? This is perfect for foam core, I can even make a version with a frame with slot for inserting different Kslots to quickly do an A/B test of the sound.
Seems to me like most of the K-slots pictured on the various iBIBk builds were small enough that a straight cut would have about the same effect. Too really do its thing, the K-slot has to be significantly large compared to the pipe it's trying to de-Q. Here is the K-slot in its purest form:
Transylvania Power Company "The Tube" and a similar-sized brass tube I made.
IG
Transylvania Power Company "The Tube" and a similar-sized brass tube I made.
IG
Yes, I believe they were largely for aesthetics rather than any supposed acoustical benefits. Might help a little.
In case anyone is interested, I started the build on the flat BIB or FIB, it's in the BIB thread. Pretty straight forward build so far.
http://www.diyaudio.com/forums/full-range/66173-terry-cains-bib-why-does-work-does-anyone-have-those-fostex-craft-handbooks-514.html
http://www.diyaudio.com/forums/full-range/66173-terry-cains-bib-why-does-work-does-anyone-have-those-fostex-craft-handbooks-514.html
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The K-Tube is a real good and natural-sounding waveguide IMO. Karlson-evangelist Freddy has been recommending them for years, stressing how easy it is to replicate it with schedule 40 PVC, yet very few people seem to have actually tried it. In the spirit of this thread, easy enclosure replication with foam-core, I'll also recommend an easy K-Tube replication with PVC. It's as easy as printing out and cutting a half-ellipse pattern to wrap round your tube and mark where to cut. The TPC tube is 5.3" long, 1" I.D. It really needs a compression driver IMO, but might work with a dome tweeter of the same diameter, I have not tried though. The radiation pattern is indeed asymmetric, with a wide dispersion. Listening angle is usually ~30° "down the slot side". It's probably what matches a Karlson bass/mid enclosure best and should work well with direct radiators or other midbass/midrange horns too.
IG
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I had a few sheets of foam-core left, so I built a small pipe for FF85WK yesterday, for kicks mostly. 30" long, which actually tunes right to driver Fs, 115Hz. I just wrapped the 20"x30" sheet into a 5"x5" square tube, driver located at 1/5 down the line, sealed with duct tape. It had decent bass output with my ear to the pipe's mouth, but even in corners, it would not couple this into the room much. My small BLH design for FF85WK works much better, does not even need corner placement and can work in the room center, placed on the floor. Plays decent down to 70-80Hz.
I also built a mini RJ cabinet for the old FF125K, with some heavy corrugated cardboard some years back.
IG
I also built a mini RJ cabinet for the old FF125K, with some heavy corrugated cardboard some years back.
IG