Furiously vibrating La Scala cabinets

[fini]

Someone is selling some (as I recall) KG4.5's on Ebay right now with a vibration fix involving what looks like about a roll of duct tape. If I knew how to do a link, I'd do it for y'all.

Cheers, fini

[sunnysal]

Thanks DJK for the info...though I have a hard time deciphering that photo in the link...is there some text that describes what was done there? thanks, Tony

[djk]

The photo is the back end of a homebuilt cornerhorn.It may look a little odd as it has a woofer loading hatch on either side.The tailboard is not installed in this photo.Here is a shot of the same speaker from the front. http://www.artandaudio.com/kfront.jpg The strips of plywood go from top to bottom along the opening that fits into the corner.

[John Warren]

this is a picture of a reinforcement method for the Klipschorn side wall that was developed by PWK and is contained in the original plans. Each

"tab" has two screws thru it a glued. Klipschorns made sometime after the 80's eliminated this stiffening method, why I don't know.

I have recently completed a second pair that utilize 3/4" side walls and 3/4" V-panels with stiffening ribs down the backs. These don't "ring" like the stock 1/2" units.

This message has been edited by John Warren on 08-19-2001 at 06:31 AM

[Colin]

as you know I "sand bagged" my big old horns with great results. I found that it is an extremely low cost, simple, easy to do and a strange, but effective, tweak:

http://www.enjoythemusic.com/magazine/equipment/1299/sandbagging.htm

I now use 20 lb. dark gray Yorkstone paving stones on top of thin pieces of Styrofoam to weigh the speakers down. I rate the tweak as a one or two on a scale where 8 to 10 are the best speakers. It does not compare to having subs or the right amplifier. Too cheap not to do it. :

This fix leaves the speaker exterior untouched. I would glue pieces of plywood panel to the inside of the LaScalas. They should cover as much space as possible. Although the thicker the better, I should think that 1/2" or 3/4 would be fine. I would then screw the panels down. Be careful not to mar or scratch the exterior of the LaScalas in any way. I have not tried this yet, so do as I say, not as I do. º

Here is the key. Doubling the thickness of the walls increases their stiffness and rigidity by a factor of four (I read that somewhere ¡V do not know where, here?). So even a small dampening of interior wall makes a big difference in the stiffness of the cabinets.

Many high end speaker cabinets are very solid and very stiff. My favorite examples are the B&W 800 series. They must use a special Italian marble that looks just like cherry wood, because rapping their bass units with your knuckles barks your skin like knocking on solid stone.

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big old Cornwalls, Bottlehead 2A3 Paramour tube amps, Dynaco series II tube pre-amp, Rotel CD player, KSW200 & LF10 subs

[sunnysal]

thanks John, Djk...John, might be a little tough to retrofit those supports into my k-horns...angle tough to find, etc...but it looks like a good idea...wonder why they stop doing it? thanks, Tony

[Dick]

Ray,

I tried this as an experiment with my la Scalas. I made and I-beam out of 3/4" plywood, put felt on the ends to avoid scratching the cherry veneer I had lovingly put all over them and then clamped the I-beam in the mouth of the horn woth 4 small clamps from Home Depot. I tried several positions including the 2/5 ratio suggested by Bill McD. I cranked them up more than normal but never noticed a change. Of course I hadn't heard a problem before I tried the experiment. It did however make a great difference in the movement of the sides of the la Scalas. If you've got a little extra time to kill you might find a ready solution to your problem.

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Richard Hemmings