hey magnetar - any klam design thoughts?

[freddi]

Karlson couplers and klam asymmetric projectors can be fun - but theres not a set of rules on design other than to look at originals (Metro has a K-woofer module)

maybe Magnetar has a few observations on picking klam baffle tilt, baffle size, etc. from building and tweaking several larger klams to share,

I've only used a 40 degree wedge and opened nose like Weiss's "Rocket" Karlson for KRC and Jess Oliver used a longer nose with 25 degrees wedge.

MIke's "Roise" klam seemed to be a good performer and kept the front length reasonable.

Freddy

[moray james]

maybe you and Mike could try something? I read through a bunch of Ged Lee's waveguide thread the other day. Why not try a inserting a cylinder of open cell foam into a K-Tube? Let me know if it works if you give it a go. Regards Moray James.

[freddi]

hey Moray - - I don't have any foam - maybe Mike can try it - imo Transylvania's k-tube is already near-perfeKt and a very good waveguide.

since U've built so many regular couplers, this thread could use some design rules input from you. I could never quite figure out the size and angle constraints of a coupler's visible volume vs the load or tuning it can do.

I hope you post a thread on the guitar coupler

Freddy

ps one thing I forgot to mention which needs investigation is the sonic effects of the first half of a coupler's flare - a small change in gap will not show on RTA but can make a huge difference in tone - -some couplers (not all) might benefit from larger starting gaps and playing with the first few inches of flare and this would be one means of tuning them to specific application or wants.

CN seems to think lower Xover can allow larger starting gap than using coaxial.

I had one little 18" coupler with 1.2" gap and it sounded great - large gap helped my 18" klam when running 2-way. As the slot is the real external port, system Fb tends to rise as gap is opened.

x15's 3-panel curved reflector made worse ground-plane graphs than a 10 degree slant board. a perpendicular board as in K15 and the first k12 may be pretty good for some regular Karlson type. Front shelf may be useful too. Rear shelf chokes can help.

[Magnetar]

Originally posted by freddi
Karlson couplers and klam asymmetric projectors can be fun - but theres not a set of rules on design other than to look at originals (Metro has a K-woofer module)

maybe Magnetar has a few observations on picking klam baffle tilt, baffle size, etc. from building and tweaking several larger klams to share,

I've only used a 40 degree wedge and opened nose like Weiss's "Rocket" Karlson for KRC and Jess Oliver used a longer nose with 25 degrees wedge.

MIke's "Roise" klam seemed to be a good performer and kept the front length reasonable.

Freddy

I only built the Rosie as far as sealed Klams go - others were open not reflex. 'Rosie' is still around but tough to get out of the room seeing the cabinets are like 160 lbs a apiece - A whole lotta Rosie

Foam in the tube is like foam in a horn. A big waste of sensitivity.

[moray james]

no argument regarding foam and loss of sensitivity. That said a k-Tube ought to be as close to ideal in terms of lauching planar waves (at the throat) and keeping that wave planar along the tube. As far as I understand it that should account for as low as it gets HOM's. There in lies my interest. Should stuffing the tube with appriciate open cell foam result in better sound (putting aside sensitivity issue) then that would be saying a lot about the impact of HOM's. Of course if you could not hear any difference it might just mean that the tube was so free of HOM's that the foam made no noticable difference at all. In any event stuffing a small ID tube is as easy an experiment as it gets so what the heck?

[Magnetar]

Originally posted by moray james
no argument regarding foam and loss of sensitivity. That said a k-Tube ought to be as close to ideal in terms of lauching planar waves (at the throat) and keeping that wave planar along the tube. As far as I understand it that should account for as low as it gets HOM's. There in lies my interest. Should stuffing the tube with appriciate open cell foam result in better sound (putting aside sensitivity issue) then that would be saying a lot about the impact of HOM's. Of course if you could not hear any difference it might just mean that the tube was so free of HOM's that the foam made no noticable difference at all. In any event stuffing a small ID tube is as easy an experiment as it gets so what the heck?

I jumped to a conclusion making that statement without even trying it- let me actually try it with the tube - please give me a couple days - we all know it will kill some of the output but what else will the foam do? (subjective listen and a fast measurement should indicate something)
Cheers,
Mike

[freddi]

hey Magnetar - one thing we don't fully know is how much we can squeeze a Karlson's front chamber and still get some useful coupled-cavity and spring action --I want to say they don't work but experience says dynamically, Karlson couplers can do well subjectively compared to reflex or some horn.

Karlson wanted a reverb effect and that alone affects the perception of highs saying coming off a coax tweeter. In normal coupler I think the upper half of the device and its aperture in that region affect tonality and some (but not every) couplers/speaker combos might work best with larger gap

Karlson on a good day might be nonsense devices that work well - or "accepted" technology doesn't work (and sound) as well as some scientists might wish to think.

whats your opinion of the Transylvania K-tubes? - still wanna given them to me ? LOL - -I would not part with mine and years previous to those used 1" ID pvc tubes and thought those were fun.

got any ideas on midbass couplers??? - how about a portable K-boombox?

Fred

[SamL]

Hi Freddi,

Is there a web site about Karlson speaker and its various design? It look very much like an art. Well, I am a newbi in this with Magnetar pointed me to look at Karlson Klam. Doing a search and your name appear on almost all post with Karlson so I guess you are the best person to ask. Not quite sure where to start other than reading endless thread of discussion.

Thanks

[Saturnus]

Originally posted by freddi
how about a portable K-boombox?

I have been ponding the same for quite some time. The Karlson appeture design with it's ability to make the speaker audibly disappear would be a considerable benefit to my boombox, however I find it extremly difficult to work a design that is based so much on guess work, and also it's damn near impossible to shrink so much that it would fit my design specifications.

Has anyone tried making one where the appeture is divided into several smaller ones? I'm thinking that it might be possible to have an oversized grill (like a 12" grill for a 10" woofer) and cutting out 3 or 4 smaller appetures in the grill. With proper depth and angling behind it might be possible for that to work.

[freddi]

Job Ulfman's "Karlson Speaker Project" site is still up but his forum quit in 2003
http://home.planet.nl/~ulfman/

Karlson's original designs and aspect are the reference with K15 being a logical start. (K15 seems liked by Cogent's designers) "Klam" refers to Karlson's asymmetric projector but the term sometimes used for any Karlson speaker.

a lot of the tonal control is probably in the first (starting) half of the aperture. John Karlson's K15,and K12 used radial arc wings.

Karlson's open-end waveguide HF is interesting - maybe Magnetar will give some impressions of how the Transylvania version sounds

one recent Karlson builder seems happy with Gauss 5181 K18 whihc is around 10 cubic foot external bulk.

John Karlson said they would not "work" without a hard coating in the front chamber which I interpret was needed to preserve a lively HF balance with coaxial and dual-cone speakers, Jess Oliver's Phase III vocal projector (Karlson's 10" klam) had a 0.060" sheet of plexiglass along its top plate.

I had a lot of posts with Karlson's patent references - a Goole patent search would find them quick.

theres some art involved in new couplers and it would be a good idea to have a test coupler with removable wings which can "swivel" on cleats to alter the gap and flare; adjustable area vent; adjustable rear lowpass choke. Moderately low Q seems to be a good idea.

*****************
re:Boombox - you'd basically treat the coupler like a bandpass box to see response - a coupler with 10" (beta 10cx) had a coupled cavivity peak around 210Hz - it needed work as that peak was a bit much for hifi - if the rear chamber had been tuned higher then perhaps the passband would been flatter (with less LF) - Metro truncated the aperture in their T15 and used a fold-back stub to gain the front chamber air-mass.

15" PHL woofer - metro T15


here's a Karlson 8 copy with 3-slit vent and a Sammi 8" with QTs ~0.38 in half space with mic on ground vs K12 with 80oz magnet 70Hz coax and a 15" Silver Iris coax - theres rise in ~ the 3rd Z peak region -- a stock K8 probaby has Fb around 85Hz or so.. Some of the "hit" and reberberatiion is controlled in the first few inches of slot. T15 might not have much of this effect (?) I could put a wad of polyfill in the K*'s first inch and change the impression of its tone.


here's stuff I posted with impedance graphs
http://db.audioasylum.com/cgi/m.mpl?forum=hug&n=115688

Freddy