Bloated speakers/weight wise

[QUOTE]..."The problem involves lowering the sonic contribution of the speaker cabinet, which at some frequencies can amount to 40% of the overall sound emitted by the speaker"...[END QUOTE]

Try this some time...Next time your listening to music, press one ear tightly to the cabinet and plug the other ear. When I did this, what I heard was not good. If I could magically turn of the cabinet, I wonder how much better it would sound, you know, like an A, B comparison.

Macrojack: What you're essentially saying is that if you turn down the volume, the cabinet will move less. D'oh! :-)

Seriously though, if you want to achieve the same lower-frequency SPL in-room, you have to move the same amount of air. Can be done through either larger driver area or greater driver excursion. Both have engineering challenges if you want to reduce distortions of the driver (and therefore of the reproduced signal) in several forms. So some designs involve using many LF drivers, which can reduce both area and excursion on a per-driver basis, at the expense of increased cost for the multiple drive units and larger cabinets to house them all (which, to the topic at hand, obviously makes for heavier speakers). But the other trend in the industry has been toward EQ'ed subwoofers with small, inconspicuous cabinets, and these drivers have some amazing levels of peak excursion, at the expense of accepting increased distortion in an area where the ear is less sensitive to it, and targeted primarily toward end users who care more about movie soundtrack FX than music quality. Some of these little monsters can move around the floor under high SPLs if not spiked.

My speaker has 3/4 inch fab board, they stand 4 ft tall, good depth, narrow though, and weigh in at 70 lbs each. I'm only missing the lower 20-40 hz's. Heres a story that shows how a light speaker can be a benifit. When katrina was on the way I moved them upstairs on sat night, just to be safe, in case the streets flooded, as happens now and then, though my first floor is 4 feet above street level. When I saw the first wave of flood water comming from the 17th street break, 20 minutes after I heard the levee go "boom...booom" the water then rose a foot/every 30 minutes. Now how in the world could I alone could move a speaker more than 150 lbs up a awkward staircase. 70 lbs was fairly easy, but not something I'd like to do often. Lets say you decide to sell a speaker that weighs in at more than 150 lbs. Its a real issue.
Lets get real about weight. Fat is not good for us, nor for speakers :-)

Did I just see Ecruz mention a speaker at 1/2 ton. Well of course its not home model, which we need to limit this contest to. So far the Wilson's X2's 1100 lbs, of course minus crate weight!!!

Onhwy61 wrote:

"The easiest way to limit the cabinet's output is to make it massive and less likely to be sympathetically excited. There are other ways to make the cabinet highly rigid and inflexible, but they are expensive (contrained layer, exotic materials, etc.)."

I don't agree that it's as simple as saying that making something massive makes it "less likely to be sympathetically excited". What that does, all other things being equal (which they're often not), is lower the frequency at which sympathetic vibration occurs. I don't pretend to have anything like a comprehensive grasp of the subject (and seriously doubt that even many speaker designers do), but do feel it's a lot more complicated than just adding mass to deal with the problem. Shape, size, density, points of contact (for both damping and exciting elements), materials' intrinsic damping and rigidity properties, all go into the mix. If you add mass in the wrong shape or the wrong location or use the wrong material, resonance will worsen instead of improve, only shifted in frequency. Mass in and of itself isn't the answer to anything in this area, it seems to me, and if you can achieve the same intended result while using less mass I think it's always better, and not necessarily more expensive all things factored in (weight has its own costs).

Zaikesman, I agree that it is more complicated than my earlier post presented, but I don't think I'm incorrect in stating that adding mass is the easiest and cheapest way to deal with cabinet vibration. It's not a perfect solution, but it does work fairly well. Going from 1/2 inch to 3/4 inch MDF or doubling up layers of MDF (or plywood) is a tried and true method to increase cabinet rigidity. There are better ways to achieve the same end like CNC milled aluminum, carbon fiber layers, concrete over wood, or even the interlocking jigsaw pieces as used by Sonus Faber. You could also take a completely different course and go for a cabinet thats extremely light yet sufficiently rigid with the goal being a very quick dissipation of the drivers' backwave energy. Any of the alternative methods is more costly than the somewhat unsophisticated approach of adding mass. It's a brute force approach to solving a problem, but that doesn't mean it's ineffective. Again, as I stated earlier, adding mass has to be part of an overall speaker design concept. Used in an non-optimal context adding mass has little positive impact.