Marijan
Just to confirm that by fast we both mean speed of sound waves and not some subjective characteristic, right? The speed will only be determined by the material and the frequency will be transmitted unchanged but of course in a wide frequency spectrum some frequencies will pass with less attenuation than others. Also there may be some resonant frequencies which will be particularly prominent in amplitude. Plus the coupling reflection/refraction effects which may lead particular vibrating modes to propagate back into the audio component and then re-exit delayed. Using cones will definitely limit (most of) these reflections to one direction if for no other reason, then because the reflected wave will have a very narrow set of possible incident angles.
Good materials? A very contentios issue again. It looks like using similar materials for component, coupler and shelf because of equal mechanical impedance will provide the minimum of reflections. This is clearly not very possible in practice unless you design the whole system from the ground up. I have had good results with couplers made out of tropical hardwoods, ceramics and graphite. On top of being rigid these materials are acousically quite inert and have a pleasing (especially the wood) spectrum of resonant frequencies in the mid- and hi- range.
An interesting trend, albeit one i don't fully understand, is the use of two elastic decouplers in a sandwitch. I've been seeing a lot of commercial stands recently which employ a combination of airbladders/elastic bands/springs/rollerballs. I expect the resonant frequencies for each decoupler need to be wide apart for such a system to work well but it's certainly worth investigating.
regards
peter
Just to confirm that by fast we both mean speed of sound waves and not some subjective characteristic, right? The speed will only be determined by the material and the frequency will be transmitted unchanged but of course in a wide frequency spectrum some frequencies will pass with less attenuation than others. Also there may be some resonant frequencies which will be particularly prominent in amplitude. Plus the coupling reflection/refraction effects which may lead particular vibrating modes to propagate back into the audio component and then re-exit delayed. Using cones will definitely limit (most of) these reflections to one direction if for no other reason, then because the reflected wave will have a very narrow set of possible incident angles.
Good materials? A very contentios issue again. It looks like using similar materials for component, coupler and shelf because of equal mechanical impedance will provide the minimum of reflections. This is clearly not very possible in practice unless you design the whole system from the ground up. I have had good results with couplers made out of tropical hardwoods, ceramics and graphite. On top of being rigid these materials are acousically quite inert and have a pleasing (especially the wood) spectrum of resonant frequencies in the mid- and hi- range.
An interesting trend, albeit one i don't fully understand, is the use of two elastic decouplers in a sandwitch. I've been seeing a lot of commercial stands recently which employ a combination of airbladders/elastic bands/springs/rollerballs. I expect the resonant frequencies for each decoupler need to be wide apart for such a system to work well but it's certainly worth investigating.
regards
peter
WHY CONES ARE CONES.
Hi,
Forcing the energy that is traveling through the cone to intersect the next surface at a right angle maximizes your chances of getting this energy to penetrate through that surface.
That's one of the main "points" of a cone or a spike- to present the mechanical energy being led out of the component at a 90° angle to the supporting surface.
I'll it once more: funnelling.
Ciao,
Hi,
Forcing the energy that is traveling through the cone to intersect the next surface at a right angle maximizes your chances of getting this energy to penetrate through that surface.
That's one of the main "points" of a cone or a spike- to present the mechanical energy being led out of the component at a 90° angle to the supporting surface.
I'll it once more: funnelling.
Ciao,
Peter
Yes, we are talking about same thing.
I was thinking about those sendwiches. Is there a point to try to cancel out (by combining diferent resonant frequencys of diferent materials) the posibility of resonace which can apere by interaction betwen platform vibr. and airborne frequency of vibration, efecting to platform.
Thank`s Peter for your explanations and sugestions.
Steve, I want vibrations out of my sistem. Let say that my subjective taste of music reproduction, require that. I`d be glad if you could share some practical sugestions based on your expirience with audio equipment and knowlidge of phisics. Any ideas welcome. Thanks and good night!
regards
Marijan
Yes, we are talking about same thing.
I was thinking about those sendwiches. Is there a point to try to cancel out (by combining diferent resonant frequencys of diferent materials) the posibility of resonace which can apere by interaction betwen platform vibr. and airborne frequency of vibration, efecting to platform.
Thank`s Peter for your explanations and sugestions.
Steve, I want vibrations out of my sistem. Let say that my subjective taste of music reproduction, require that. I`d be glad if you could share some practical sugestions based on your expirience with audio equipment and knowlidge of phisics. Any ideas welcome. Thanks and good night!
regards
Marijan
Marijan
I doubt you really stand a chance to cancel out the fundamental resonances of two elastic systems without very elaborate tuning. More likely the concept is to use two filters with cutoff frequencies separated by at least an octave and thus getting a steeper filtering above a certain frequency but i may well be wrong.
SE
I've noticed your fondness for Newtonian physics dealing with vibrations but in the case of sound waves there are lots of similarities with optics. That's why i use terms as reflection, refraction, incident angles. It's easy to imagine full internal reflections as well when dealing with a substance denser than air. In this light it's easy to see that very few vibrational modes will be able to enter a cone efficiently through the sharp end. Moreover, because of the narrow point of contact, you might not even be picking any vibration back - surely the surface on which the cone resides has only a limited number of active vibrational nodes. It is interesting to establish whether insignificant repositioning of the cones on the underlying surface does perceptibly alter the sound.
I may certainly be wrong on all accounts - i stopped being a physicist about 20 years ago and i have absolutely no desire to enter into an exhaustive argument. That's why i normally limit myself to subjective opinions.
regards
peter
I doubt you really stand a chance to cancel out the fundamental resonances of two elastic systems without very elaborate tuning. More likely the concept is to use two filters with cutoff frequencies separated by at least an octave and thus getting a steeper filtering above a certain frequency but i may well be wrong.
SE
I've noticed your fondness for Newtonian physics dealing with vibrations but in the case of sound waves there are lots of similarities with optics. That's why i use terms as reflection, refraction, incident angles. It's easy to imagine full internal reflections as well when dealing with a substance denser than air. In this light it's easy to see that very few vibrational modes will be able to enter a cone efficiently through the sharp end. Moreover, because of the narrow point of contact, you might not even be picking any vibration back - surely the surface on which the cone resides has only a limited number of active vibrational nodes. It is interesting to establish whether insignificant repositioning of the cones on the underlying surface does perceptibly alter the sound.
I may certainly be wrong on all accounts - i stopped being a physicist about 20 years ago
and i have absolutely no desire to enter into an exhaustive argument. That's why i normally limit myself to subjective opinions.regards
peter
Re: WHY CONES ARE CONES.
I don't see that you're forcing anything to a right angle.
Think about it.
Take a panel with three cones attached, pointy side down, which couple to a second panel which is resting on some frictionless surface.
If what you say is true, then applying a lateral force to the top panel wouldn't result in any lateral movement of the assembly because the lateral force is translated to a force 90 degrees to the bottom panel.
Again, I don't see that it does. And as of yet I haven't seen any evidence that this is the case.
And I'll say it once more: I think the whole "funnel" thing is little more than the result of naive intutition. "Hey, it LOOKS a lot like a funnel."
se
fdegrove said:
I don't see that you're forcing anything to a right angle.
Think about it.
Take a panel with three cones attached, pointy side down, which couple to a second panel which is resting on some frictionless surface.
If what you say is true, then applying a lateral force to the top panel wouldn't result in any lateral movement of the assembly because the lateral force is translated to a force 90 degrees to the bottom panel.
Again, I don't see that it does. And as of yet I haven't seen any evidence that this is the case.
And I'll say it once more: I think the whole "funnel" thing is little more than the result of naive intutition. "Hey, it LOOKS a lot like a funnel."
se
analog_sa said:
Sure, you can consider the structural behavior of the cone itself if you'd like, but those effects are pretty much irrelevant in the context of the primary issue here, that being the cone's performance as a rigid mechanical coupler.
And no, I know it's not perfectly rigid. But compared to the rigidity of large, thin equipment panels that they're to be coupling to, it's not even in the ballpark.
It's like worrying about the dynamic behavior of a loudspeaker voicecoil former while ignoring the movement of the loudspeaker's cone.
And while analyzing the microscopic can be fun, it still doesn't make the case for the "funneling" effect being claimed.
I don't see why that would be the case. Though if it were, then it would basically refute Frank's claims. If vibrational modes can't be stimulated efficiently by entering the sharp end, then neither will any energy efficiently exit the sharp end.
Well, whether the flat end of a cylinder or a small point, both would appear as rather an "open circuit" to the panel they're coupling to.
I may certainly be wrong on all accounts - i stopped being a physicist about 20 years ago
Hehehe. I tend to limit myself to physics seeing as I don't think my subjective opinions terribly meaningful to anyone other than myself. I mean, if they did, then they'd be more akin to objective opinions.
se
Re: Re: SKIPPING STONES.
Sheesh. You're just parroting more marketing literature.
<a href="http://www.symposiumusa.com/tech1.html">http://www.symposiumusa.com/tech1.html</a>
What about all those BOOKS you've been telling me to go read? Why don't you quote from some of those rather than marketing literature from companies in the business of selling cones?
*sigh*
se
Sheesh. You're just parroting more marketing literature.
<a href="http://www.symposiumusa.com/tech1.html">http://www.symposiumusa.com/tech1.html</a>
What about all those BOOKS you've been telling me to go read? Why don't you quote from some of those rather than marketing literature from companies in the business of selling cones?
*sigh*
se
Re: SIGH...
I don't ignore them. I'm just not going to go and buy a bunch of books just on your say so which may not contain anything which supoprts your claim.
Had you quoted at least SOMETHING from one of those books, then I could have at least determined whether it was worth spending money on.
It's apparent that you don't even own any of these books yourself. If you did, you wouldn't be forced to parrot marketing literature from a cone manufacturer.
It's also apparent that all you seem to "know" about the subject is what you've read in marketing literature rather than through any understanding of physics.
se
fdegrove said:
I don't ignore them. I'm just not going to go and buy a bunch of books just on your say so which may not contain anything which supoprts your claim.
Had you quoted at least SOMETHING from one of those books, then I could have at least determined whether it was worth spending money on.
It's apparent that you don't even own any of these books yourself. If you did, you wouldn't be forced to parrot marketing literature from a cone manufacturer.
It's also apparent that all you seem to "know" about the subject is what you've read in marketing literature rather than through any understanding of physics.
se
Re: Re: SIGH...
there exist places called libraries (or lybaries as G.W. would call them). They are places where one can look for and read books without buying. You can sneak into university libraries even if you are not a student (except Harvard which is a real pain in the *** about it) and pretty much read whatever you wish.
Steve Eddy said:
there exist places called libraries (or lybaries as G.W. would call them). They are places where one can look for and read books without buying. You can sneak into university libraries even if you are not a student (except Harvard which is a real pain in the *** about it) and pretty much read whatever you wish.
Well, I've been reading through the Symposium web site and man, these folks don't even have a clue about their own products. That this site should be used as any sort of reference is laughable.
Here's perhaps the most egregious example, concerning their most popular product, their Rollerblock "isolation" devices:
<i>As the Rollerblock body moves, it pushes the ball and the component up the sides of the cup, dissipating the energy as work.</i>
Pushes the ball and the component up the sides of the cup dissipates energy?
Uh, no. It's actually STORING energy. What goes up (the sides of the cup) must come down (the sides of the cup). And since the ball and the cup are made from very hard materials, and due to the spherical shape of the ball, there's next to no energy dissipated (i.e. losses). Nearly all of it is stored and simply returned to the system.
While the Rollerblock is claimed to isolate the component from horizontal movement of the shelf, what they're actually doing is converting horizontal motion to vertical motion, transferring that motion to the component. And the Rolloerblock is designed to COUPLE vertical motion which makes it even more effective at converting horizontal motion to vertical motion.
Brilliant.
se
Here's perhaps the most egregious example, concerning their most popular product, their Rollerblock "isolation" devices:
<i>As the Rollerblock body moves, it pushes the ball and the component up the sides of the cup, dissipating the energy as work.</i>
Pushes the ball and the component up the sides of the cup dissipates energy?
Uh, no. It's actually STORING energy. What goes up (the sides of the cup) must come down (the sides of the cup). And since the ball and the cup are made from very hard materials, and due to the spherical shape of the ball, there's next to no energy dissipated (i.e. losses). Nearly all of it is stored and simply returned to the system.
While the Rollerblock is claimed to isolate the component from horizontal movement of the shelf, what they're actually doing is converting horizontal motion to vertical motion, transferring that motion to the component. And the Rolloerblock is designed to COUPLE vertical motion which makes it even more effective at converting horizontal motion to vertical motion.
Brilliant.
se
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