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Looper's Delight
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Linsay, Sorry, not trying to beat you with a stick, but rather trying to understand the physics of what is occuring. I was intrigued by the comments made last week, and my initial experience of the bowls caused me to doubt the assertions. The only similarity of the cone and bowl that I was trying to make was radiating surface area. I addressed that because of the assertion that the bowl was too small to generate the low fundamental. I have built loudspeaker enclosures for the past 30 years. A major lessen I learned is that what we think is a rigid box, actually radiates a considerable amount of sound. One would think that the seemingly rigid box could flex such a tiny amount that it would not radiate much sound. However, the surface area of the boxes panels are quite large compared to the surface area of the speaker cones, so that a small movement in the box wall contributes considerably to the radiate sound field. This is why companies like Bowers and Wilkins (B&W) go to such extremes as using laser interferometry to analyze loudspeker walls' miniscule vibrations. This lead to them developing fibercrete walls (fiberglass and concrete) and heavely ribbed walls to make the structure so rigid that the movement is minimized. Cleary the modes of vibrations of the bowl and cone loudspeaker are very different. In the bowl, resonances are desired and required to create the sound. In the cone, we don't want modal vibrations, but rather piston action (to create the pressure/rarefaction). Again, comanyies (like B&W) analyze the vibrational modes of diaphragms to see if there are modal vibrations and design them out. I may be full of shit, but we can measure this easily and not worry about our beliefs and opinions. I would love to try a 20" bowl. I haven't seen one that large locally. Some of the smaller ones I tried had so much vibrational energy (the sound kind, not the new age kind) I could hardly hold and play them for much time. They made my hands buzz afterword. regards, bret --- lindsay@pavestone.com wrote: > > I'm not claiming to be an acoustic engineer. So, I will already > admit > defeat if that's what's due me. However, I think there is a fallacy > between drawing a similarity between the way a resonating cone or > half-sphere (like a bowl) produces sound and that produced by the > two-way > excursion of a rigid cone (a speaker). The surface area argument > just > doesn't feel right to me when we're not talking about excursion, but > rather > a three-dimensional resonance. And for right now, "feel" is all I've > got. > I'm still looking, though. > > Will someone with a real working knowledge of this take the baton? > I'm > foundlessly proselytizing and Bret threatens to beat me with a bigger > stick > than I'd care to take. > __________________________________________________ Do You Yahoo!? Yahoo! Messenger - Talk while you surf! It's FREE. http://im.yahoo.com/