Re: THE ALHABET.
Yeah. I'm sure Michael Jackson feels the same way.
So then it's a matter of your having a problem explaining things that you understand?
You're the one who invoked the physics here, not me. You're the one who claimed that they functioned different physically (and that's what I was questioning, not whether people heard any differences or not). You're the one who said they'd have a field day discussing the physics.
Look, if you don't want to talk about physics, then don't bring up anything which has to do with physics. Just stick to what you hear.
I've tried springs. And over the past 20 some odd years I've been playing around with audio, I've tried pretty much everything else as well. But what I happen to prefer subjectively hasn't any particular relationship to physics.
As I've said a number of times in the past, I keep my subjective enjoyment of audio separate from any underlying physics. When I talk about my subjective enjoyment, I talk about my subjective enjoyment and don't bring any physics into the matter. When I talk about physics, I talk about physics and don't bring my subjective enjoyment into the matter.
You said you'd have a field day discussing physics. I assume you were sincere and looked forward to a physics discussion. But it looks like I've been stood up.
se
fdegrove said:
Yeah. I'm sure Michael Jackson feels the same way.
So then it's a matter of your having a problem explaining things that you understand?
You're the one who invoked the physics here, not me. You're the one who claimed that they functioned different physically (and that's what I was questioning, not whether people heard any differences or not). You're the one who said they'd have a field day discussing the physics.
Look, if you don't want to talk about physics, then don't bring up anything which has to do with physics. Just stick to what you hear.
I've tried springs. And over the past 20 some odd years I've been playing around with audio, I've tried pretty much everything else as well. But what I happen to prefer subjectively hasn't any particular relationship to physics.
As I've said a number of times in the past, I keep my subjective enjoyment of audio separate from any underlying physics. When I talk about my subjective enjoyment, I talk about my subjective enjoyment and don't bring any physics into the matter. When I talk about physics, I talk about physics and don't bring my subjective enjoyment into the matter.
You said you'd have a field day discussing physics. I assume you were sincere and looked forward to a physics discussion. But it looks like I've been stood up.
se
The purpose of the cones is ostensibly to "funnel away" vibrational energy within the equipment chassis itself, not isolate the equipment chassis from a vibrating rack or shelf.
While springs can be good at isolating an equipment chassis from a vibrating rack or shelf shelf (i.e. structure borne vibration), if the "problem" is virbrations extant in the equipment chassis itself due either to internal sources such as power transformers or external sources such as airborne vibration from the loudspeakers, "lossless" springs would do nothing to help in this regard unless you were wanting to keep equipment vibrations from getting into your rack or shelf (isolation is bi-directional).
Otherwise, the vibrational energy will remain ringing away in the chassis until whatever losses there are in the chassis itself eventually convert that energy into heat.
So if you want to control vibration, as I said quite a few posts back, first you have to define what the actual "problem" is. The ideal solution to a given problem isn't necessarily the ideal solution to other problems.
If the "problem" is structure borne vibration, then isolation such as springs would be effective. Coupling such as cones would not be effective.
If the "problem" is airborne vibration, you can either acoustically isolate the system with sound absorption materials, or apply damping to the chassis to convert the energy to heat as quickly as possible.
If the "problem" is equipment borne, the solution is pretty much the same as above. You can isolate the equipment from the source of vibration by putting power supplies (or power transformers at least) into a separate chassis. Or you can again apply damping to the chassis to convert vibrational energy into thermal energy as effectively as possible.
Cones or any other sort of rigid foot are nothing more or less than mechanical couplers and their effect will depend entirely upon what exactly they are coupling to.
If they're coupled to a rigid surface, or some isolating device such as a spring, vibrational energy in the equipment chassis will remain in the equipment chassis.
If they're coupled to a lossy (i.e. damping) medium, some small amount of energy will be converted to heat. I say some small amount because the surface area contact between the chassis and the damping medium will be small for a few relatively small equipment feet.
You'll get a greater amount of damping as you increase the surface area with which the chassis contacts (either directly or through coupling feet) the damping medium.
Of course this all deals with vibration from an objective standpoint and assumes that vibration in equipment chassis is bad and should at best be eliminated completely or at least reduced as much as practically possible.
What one ulitmately prefers subjectively can of course vary widely among different individuals. Some may prefer a chassis that vibrates more, others may prefer a chassis that vibrates less.
On issues of subjectivity, there's really nothing to argue as whatever "works" for a particular individual is the only "right" approach for that individual. Other individuals notwithstanding.
se
While springs can be good at isolating an equipment chassis from a vibrating rack or shelf shelf (i.e. structure borne vibration), if the "problem" is virbrations extant in the equipment chassis itself due either to internal sources such as power transformers or external sources such as airborne vibration from the loudspeakers, "lossless" springs would do nothing to help in this regard unless you were wanting to keep equipment vibrations from getting into your rack or shelf (isolation is bi-directional).
Otherwise, the vibrational energy will remain ringing away in the chassis until whatever losses there are in the chassis itself eventually convert that energy into heat.
So if you want to control vibration, as I said quite a few posts back, first you have to define what the actual "problem" is. The ideal solution to a given problem isn't necessarily the ideal solution to other problems.
If the "problem" is structure borne vibration, then isolation such as springs would be effective. Coupling such as cones would not be effective.
If the "problem" is airborne vibration, you can either acoustically isolate the system with sound absorption materials, or apply damping to the chassis to convert the energy to heat as quickly as possible.
If the "problem" is equipment borne, the solution is pretty much the same as above. You can isolate the equipment from the source of vibration by putting power supplies (or power transformers at least) into a separate chassis. Or you can again apply damping to the chassis to convert vibrational energy into thermal energy as effectively as possible.
Cones or any other sort of rigid foot are nothing more or less than mechanical couplers and their effect will depend entirely upon what exactly they are coupling to.
If they're coupled to a rigid surface, or some isolating device such as a spring, vibrational energy in the equipment chassis will remain in the equipment chassis.
If they're coupled to a lossy (i.e. damping) medium, some small amount of energy will be converted to heat. I say some small amount because the surface area contact between the chassis and the damping medium will be small for a few relatively small equipment feet.
You'll get a greater amount of damping as you increase the surface area with which the chassis contacts (either directly or through coupling feet) the damping medium.
Of course this all deals with vibration from an objective standpoint and assumes that vibration in equipment chassis is bad and should at best be eliminated completely or at least reduced as much as practically possible.
What one ulitmately prefers subjectively can of course vary widely among different individuals. Some may prefer a chassis that vibrates more, others may prefer a chassis that vibrates less.
On issues of subjectivity, there's really nothing to argue as whatever "works" for a particular individual is the only "right" approach for that individual. Other individuals notwithstanding.
se
Consonance ?.
Ok, I agree with all that you say in your long reply - hallelujah !
My understanding (as is yours) that hard supports (cones or cylinders) are near enough perfect couplings, and by this means the equipment and shelf act reasonably in unison, with the caveat that locations of the hard supports alter the spectral nature of the couplings, due to vibrational nodal points in the individual surfaces.
By this means mechanical feedback coupling can be 'tuned', and this may or may not produce a sonically pleasing resultant.
With equipment that is heavy and inherently dead, I find springs avoid this nodal behaviour, and to my ear is a more correct sound.
With speakers I find that spring mounting allows the cabinet to behave with it's own resonant behaviour, and when cone or hard feet mounted, this is altered and in my experience gives an un-natural hardening of the bass sounds - especially upper bass tones.
With the box as an isolated system, I also find that overall acoustic efficiency increases, and placement of the springs is FAR less critical than when using cones or hard mounts.
Eric.
Ok, I agree with all that you say in your long reply - hallelujah !
'Ostensibly' is indeed the keyword here.
My understanding (as is yours) that hard supports (cones or cylinders) are near enough perfect couplings, and by this means the equipment and shelf act reasonably in unison, with the caveat that locations of the hard supports alter the spectral nature of the couplings, due to vibrational nodal points in the individual surfaces.
By this means mechanical feedback coupling can be 'tuned', and this may or may not produce a sonically pleasing resultant.
With equipment that is heavy and inherently dead, I find springs avoid this nodal behaviour, and to my ear is a more correct sound.
With speakers I find that spring mounting allows the cabinet to behave with it's own resonant behaviour, and when cone or hard feet mounted, this is altered and in my experience gives an un-natural hardening of the bass sounds - especially upper bass tones.
With the box as an isolated system, I also find that overall acoustic efficiency increases, and placement of the springs is FAR less critical than when using cones or hard mounts.
Eric.
SPRINGS.
Hi,
What are "lossless" springs? Aren't springs lossy by their very nature?
What took you so long?
And if you put them upside down, than what happens?
They drain and they couple depending what side is up or down.
In real life there is usually going to be a combination of both structure- and airborne vibration.
Absolutely.
Ciao,
Hi,
What are "lossless" springs? Aren't springs lossy by their very nature?
What took you so long?
And if you put them upside down, than what happens?
They drain and they couple depending what side is up or down.
In real life there is usually going to be a combination of both structure- and airborne vibration.
Absolutely.
Ciao,
Re: SPRINGS.
Uh... no. They're not lossy by their very nature.
A "lossless" spring is an ideal spring.
A mechanical spring is the equivalent of electrical inductance. And just as an ideal inductor (or capacitor for that matter) has no property of resistance (loss), so an ideal mechanical spring has nor property of friction (loss).
Of course any realworld spring, such as valve springs, will have some amount of loss just as any realworld inductor or capacitor. Which is why I put "lossless" in quotes.
Nothing. I was simply restating Goldmund's (as well as your) claim as to how they supposedly function.
They couple. Just as they do when they're right side up.
No, they couple regardless of what end is up or down.
Sure. So why would you want to couple your component to a vibrating structure?
Positively.
se
fdegrove said:
Uh... no. They're not lossy by their very nature.
A "lossless" spring is an ideal spring.
A mechanical spring is the equivalent of electrical inductance. And just as an ideal inductor (or capacitor for that matter) has no property of resistance (loss), so an ideal mechanical spring has nor property of friction (loss).
Of course any realworld spring, such as valve springs, will have some amount of loss just as any realworld inductor or capacitor. Which is why I put "lossless" in quotes.
Nothing. I was simply restating Goldmund's (as well as your) claim as to how they supposedly function.
They couple. Just as they do when they're right side up.
No, they couple regardless of what end is up or down.
Sure. So why would you want to couple your component to a vibrating structure?
Positively.
se
Steve, pardon me if this has been mentioned before (no WAY I'm gonna slog through this entire thread), but your argument about the symmetry of cones is true only if the upper and lower surfaces that the cones contact are symmetrical (including the effects of gravity). For a simple case of an amp with a flexible bottom (a drumhead of sheetmetal) and a rest surface that is extremely rigid, one would expect to see a difference if the cone is pointy side up versus pointy side down. With two rigid surfaces, your argument holds true.
Two observations:
1. If a piece of equipment is microphonic, that ought to be remedied at the source. I haven't actually had a piece of solid state gear (and damned few pieces of tube gear) in my living room that showed any microphonics when the cases were excited with an impulse. It seems like a more important consideration for turntables or speakers, but that's another story. If a piece of electronic equipment doesn't show microphonics when tapped, I don't believe a cone is going to make a blessed bit of difference to the sound.
2. It would take far less energy than this thread has generated to take a chassis, attach an accelerometer (a PVDF job would be good enough) to the top surface, and look at the spectrum point up versus point down when excited by an acoustic wave or a mechanical impulse (a ball bearing dropped from a fixed height onto the bottom surface, for example).
Two observations:
1. If a piece of equipment is microphonic, that ought to be remedied at the source. I haven't actually had a piece of solid state gear (and damned few pieces of tube gear) in my living room that showed any microphonics when the cases were excited with an impulse. It seems like a more important consideration for turntables or speakers, but that's another story. If a piece of electronic equipment doesn't show microphonics when tapped, I don't believe a cone is going to make a blessed bit of difference to the sound.
2. It would take far less energy than this thread has generated to take a chassis, attach an accelerometer (a PVDF job would be good enough) to the top surface, and look at the spectrum point up versus point down when excited by an acoustic wave or a mechanical impulse (a ball bearing dropped from a fixed height onto the bottom surface, for example).
Re: WE MATE.
Think for a moment, Frank.
Let's say you've got two objects in intimate contact with a mechanical coupling. Let's say a cone.
Now, if one end of the coupler somehow couples better to an object than the other end, it's still not going to matter which end is which. The end which doesn't couple as well will always be your limiting factor.
se
fdegrove said:
Think for a moment, Frank.
Let's say you've got two objects in intimate contact with a mechanical coupling. Let's say a cone.
Now, if one end of the coupler somehow couples better to an object than the other end, it's still not going to matter which end is which. The end which doesn't couple as well will always be your limiting factor.
se
Perhaps there's something to this after all
This thread seems to be going nowhere so after I replied to Frank's last post, I thought I'd take advantage of the fact that I've a rather nice community college within walking distance so I headed on over and looked to see if they had any of the texts that Frank had mentioned previously.
They didn't but I found something else.
Frank, you want to give this a read through and see if it jibes with the other texts you'd cited?
I rarely keep any cash on me so I didn't have any money for the photocopy machines so I had to jot all this down by hand and only had about 20 minutes before the library closed. So I didn't bother copying down the big hairy equations but I think the meat and potatoes of the text is sufficient for this venue.
It's from Principles of Engineering Dynamics, by James T. Dunsel, published in 1954 by Excelsior Press, Cambridge, England.
<i>Chapter 16: Decoupling, Damping and Resonance Control
16.7. Nonlinear coupling.
The principle of action-reaction suggests but does not mandate symmetry of coupling in linear force-transmission systems. Consider two harmonic oscillators of mass M1 and M2 (Figure 16.23) having amplitudes X1 and X2 and angular frequencies w1 and w2, respectively. The oscillators are attached by a rigid coupling consisting of a circular flat plate in point contact with a cone, as indicated.
[Big hairy equations omitted]
The force per unit area at the contact point is infinite, and the
moment of force is zero. The differential moment of inertia of the cone tip is zero in the limit as the radius approaches zero. The moment of inertia of the plate, computed as the integral of circular elements of radius 0 less than r less than R, is non-zero. Taking the integral over the radius of the plate, we obtain:
[More big hairy equations omitted]
It is shown that a singularity appears in equation 16.37 as the radius of contact approaches zero. Combining the equations for conservation of energy and conservation of momentum, we may solve for the total energy transfer:
[Still more big hairy equations omitted]
Finally, taking the derivative of Equation 16.42, we obtain an expression for the rate of energy transfer:
P = [k * log(M1 / M2) * (w1 * w2) ^ 2] / r (this was easy enough to jot down)
The rate of energy transfer depends, therefore, on the ratio of the masses, the combined frequencies of oscillation, the contact radius, and the coefficient of hardness at the contact point. It can be seen that for infinite hardness or zero radius, the power transfer is infinite.
In theory, the asymmetrical coupler offers superior vibration-dampening performance in comparison to absorbtive elastomers and visco-elastic fluids.
In practice, the difficulty of maintaining ideal material characteristics at the contact point constrains the rate of energy transfer. Because of the high cost of fabrication and the recent availability of low-cost synthetic dampening materials, the asymmetric coupler can no longer be considered an economically viable solution for acoustic vibration control, and it is now
rarely seen in practical applications.</i>
I'd buy you lunch, Frank, but since I had to do your homework for you (and it was your claim, not mine), how 'bout we just call it even?
se
This thread seems to be going nowhere so after I replied to Frank's last post, I thought I'd take advantage of the fact that I've a rather nice community college within walking distance so I headed on over and looked to see if they had any of the texts that Frank had mentioned previously.
They didn't but I found something else.
Frank, you want to give this a read through and see if it jibes with the other texts you'd cited?
I rarely keep any cash on me so I didn't have any money for the photocopy machines so I had to jot all this down by hand and only had about 20 minutes before the library closed. So I didn't bother copying down the big hairy equations but I think the meat and potatoes of the text is sufficient for this venue.
It's from Principles of Engineering Dynamics, by James T. Dunsel, published in 1954 by Excelsior Press, Cambridge, England.
<i>Chapter 16: Decoupling, Damping and Resonance Control
16.7. Nonlinear coupling.
The principle of action-reaction suggests but does not mandate symmetry of coupling in linear force-transmission systems. Consider two harmonic oscillators of mass M1 and M2 (Figure 16.23) having amplitudes X1 and X2 and angular frequencies w1 and w2, respectively. The oscillators are attached by a rigid coupling consisting of a circular flat plate in point contact with a cone, as indicated.
[Big hairy equations omitted]
The force per unit area at the contact point is infinite, and the
moment of force is zero. The differential moment of inertia of the cone tip is zero in the limit as the radius approaches zero. The moment of inertia of the plate, computed as the integral of circular elements of radius 0 less than r less than R, is non-zero. Taking the integral over the radius of the plate, we obtain:
[More big hairy equations omitted]
It is shown that a singularity appears in equation 16.37 as the radius of contact approaches zero. Combining the equations for conservation of energy and conservation of momentum, we may solve for the total energy transfer:
[Still more big hairy equations omitted]
Finally, taking the derivative of Equation 16.42, we obtain an expression for the rate of energy transfer:
P = [k * log(M1 / M2) * (w1 * w2) ^ 2] / r (this was easy enough to jot down)
The rate of energy transfer depends, therefore, on the ratio of the masses, the combined frequencies of oscillation, the contact radius, and the coefficient of hardness at the contact point. It can be seen that for infinite hardness or zero radius, the power transfer is infinite.
In theory, the asymmetrical coupler offers superior vibration-dampening performance in comparison to absorbtive elastomers and visco-elastic fluids.
In practice, the difficulty of maintaining ideal material characteristics at the contact point constrains the rate of energy transfer. Because of the high cost of fabrication and the recent availability of low-cost synthetic dampening materials, the asymmetric coupler can no longer be considered an economically viable solution for acoustic vibration control, and it is now
rarely seen in practical applications.</i>
I'd buy you lunch, Frank, but since I had to do your homework for you (and it was your claim, not mine), how 'bout we just call it even?
se
MY HOMEWORK.
Hi,
If it's American food you're buying a good T-bone steak would be fine.
Actually I am surprised you could find that info at the local library at all.
I had planned on sending you some pdf files on this but I think this rather redundant now.
To reward you for all the homework you did I'll let you in on one of my favourite sources for damping materials:
E A R.
Can I have that T-bone now?
Next topic please...
Hi,
If it's American food you're buying a good T-bone steak would be fine.
Actually I am surprised you could find that info at the local library at all.
I had planned on sending you some pdf files on this but I think this rather redundant now.
To reward you for all the homework you did I'll let you in on one of my favourite sources for damping materials:
E A R.
Can I have that T-bone now?
Next topic please...
Re: MY HOMEWORK.
Well, I'm afraid you're going to be left with just the bone.
I really had high hopes for you, Frank.
I was hoping you'd come back and say something like "Steve, that's just a bunch of nonsensical gibberish" (I'm assuming you actually read it). Because that's precisly what it was.
There is no book titled Principles of Engineering Dynamics written by a James T. Dunsel. What I posted was a bunch of nonsensical gibberish that was made up by Henry Pasternack as a joke quite some years ago and was posted on one of the rec.audio newsgroups (I don't know if Google's newsgroup archives go back that far yet but you might try checking anyway).
"Dunsel" by the way is slang by the way for "idiot" though it's sometimes spelled duncel after duns/dunce.
I apologize for the deception, but you'd been so evasive and defensive about discussing any actual physics beyond words like "diode" and "funnel" and "drain" that I needed to get something of a reality check.
However if you think you have some real evidence to support your claim in the pdfs you mentioned sending, I'd be more than happy to give them a lookthrough.
Let me in on it? I've been using their stuff for years. The transformers in my InterFace box sit on custom die cut gaskets of their C-1002 Isodamp material, the PC boards sit on their Isoloss sandwich mount standoffs, and the feet are custom die cut from Isoloss VL.
Thanks anyway though.
se
fdegrove said:If it's American food you're buying a good T-bone steak would be fine.
Well, I'm afraid you're going to be left with just the bone.
I really had high hopes for you, Frank.
I was hoping you'd come back and say something like "Steve, that's just a bunch of nonsensical gibberish" (I'm assuming you actually read it). Because that's precisly what it was.
There is no book titled Principles of Engineering Dynamics written by a James T. Dunsel. What I posted was a bunch of nonsensical gibberish that was made up by Henry Pasternack as a joke quite some years ago and was posted on one of the rec.audio newsgroups (I don't know if Google's newsgroup archives go back that far yet but you might try checking anyway).
"Dunsel" by the way is slang by the way for "idiot" though it's sometimes spelled duncel after duns/dunce.
I apologize for the deception, but you'd been so evasive and defensive about discussing any actual physics beyond words like "diode" and "funnel" and "drain" that I needed to get something of a reality check.
However if you think you have some real evidence to support your claim in the pdfs you mentioned sending, I'd be more than happy to give them a lookthrough.
Let me in on it? I've been using their stuff for years. The transformers in my InterFace box sit on custom die cut gaskets of their C-1002 Isodamp material, the PC boards sit on their Isoloss sandwich mount standoffs, and the feet are custom die cut from Isoloss VL.
Thanks anyway though.
se
Re: ENTRAPMENT.
It's not about belief or disbelief.
Let me put it this way. In all the years since cones first came out, I have yet to see any real evidence to support the objective, physical claims made about them, vis a vis "mechanical diodes," "energy funnels," "drains," etc. and that they function differently depending on whether the pointy side is up or down.
All I've ever come across is a lot of hand-waving, empty claims and marketing doubletalk.
Hehehe. Nope. Everything I said about springs was wholly sincere.
se
fdegrove said:
It's not about belief or disbelief.
Let me put it this way. In all the years since cones first came out, I have yet to see any real evidence to support the objective, physical claims made about them, vis a vis "mechanical diodes," "energy funnels," "drains," etc. and that they function differently depending on whether the pointy side is up or down.
All I've ever come across is a lot of hand-waving, empty claims and marketing doubletalk.
/Eric be ware he may have tricked you on the springs tooo!!!
Hehehe. Nope. Everything I said about springs was wholly sincere.
se
Re: BETTER WAYS.
Well, if you actually understand it as you claim to, then I don't see why it should be terribly difficult to explain. I mean, it's not as if you're trying to explain it to a layperson or something.
se
fdegrove said:Well, there is a difference and oh, yes there are far more better ways to deal with vibrations this than a cone.
Nonetheless I do hear a difference with the comes facing pointy side up or down...and it can be explained on a physics level too.
Question is, can I explain it?
Well, if you actually understand it as you claim to, then I don't see why it should be terribly difficult to explain. I mean, it's not as if you're trying to explain it to a layperson or something.
se
Sorry for taking so long to reply to this, but I had to wait until after I let Frank in on the bit about the "proof" I offered last night.
Why would one expect a difference whether the rest surface is rigid or otherwise? What, specifically, do you base such an expectation on?
Perhaps. Though that's ultimately not the issue here.
Sure.
Unfortunately, I sold my Turtle Beach Fiji/Liberty AudioSuite system several years ago and tossed in a MSI ACH-01 accelerometer as a freebie.
Fortunately, the person I sold it to has just registered here. Though I don't know if he has the time or even any interest in doing such a test.
The real question is, why hasn't Goldmund, or the numerous other companies who have made and sold cones over the years done this already and featured it prominently in their marketing literature and their "technical" white papers?
se
SY said:
Why would one expect a difference whether the rest surface is rigid or otherwise? What, specifically, do you base such an expectation on?
Perhaps. Though that's ultimately not the issue here.
Sure.
Unfortunately, I sold my Turtle Beach Fiji/Liberty AudioSuite system several years ago and tossed in a MSI ACH-01 accelerometer as a freebie.
Fortunately, the person I sold it to has just registered here. Though I don't know if he has the time or even any interest in doing such a test.
The real question is, why hasn't Goldmund, or the numerous other companies who have made and sold cones over the years done this already and featured it prominently in their marketing literature and their "technical" white papers?
se
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.