Lol. Lead is one of the worst materials for sound that has ever been perpetrated on naive and gullible audiophiles. Yes, I know it seems like a good idea, all soft and heavy like. 😛 Even the esteemed Pierre Sprey at Mapleshade grew to detest lead although he was a big fan for a long time and, according to your humble scribe’s sources, had one of his employees cart out 200 lbs of the stuff to Las Vegas for use in CES shows.
Besides, mass loading simply changes the resonant frequency of the component. It is not really a substitute for real vibration isolation. I.e., mass on spring. If one is determined to use heavy mass on top of a DAC or anything else, you will have much better luck incorporating a viscoelastic material under the heavy mass, I.e., constrained layer damping. |
A DAC is what you call it? Cute! |
Old discarded dry wall would be my first choice for trying to get that special designer look to any superior audio system. And It really sets off the room.
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Comments regarding the Townshend speaker pods and isolation theory in general that I posted this morning on the Lifting Cables off the Floor thread could have been posted here on this thread with equal relevance.
cheers, Geoff Kait |
david_ten OP
352 posts
07-29-2017 9:28am
@geoffkait and others,
Is there a simple or somewhat simple way to figure out mass distribution of a component, other than eyeballing transformer postion(s) and weightier sections and going by felt weight?
Springs you can measure with a bubble level, when the top of the component is level the mass will be distributed. The only exception is a CD the top of the chassis may or may not be the exact same level as the CD transport. Obviously, or perhaps not obviously, the CD should be absolutely level during play. For roller bearings you have to determine level some other way, for example the surface on which the roller bearing sit. But the only way to determine when the system is balanced is by moving one or more bearing a little at a time until all three bearings are centered in their cups and the component doesn't get hung up in one cup when the mass off balance forces it over to one side. The component should always come back to the equilibrium position where all bearings are in the center of their cups. If the system isn't perfectly balanced the bearings cannot move freely up the shallow angle of the cups, hurting rotational isolation. But this all isn't as hard as it sounds. Once you see the bearings in action you'll understand.
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That would be true if the mass distribution of the component is uniform. But since mass is often not uniform - such as when a large transformer is located on one side of an amplifier or a motor is located on the side of a turntable - the mass should be distributed equally among the bearings to ensure the component can move freely in all directions. Obviously cords and cables must be squared away so they don’t apply forces, including rotational forces, to the delicate set up. If mass is not distributed equally more force will be applied to one or more bearings than the other one or two. So, the best arrangement for the bearings is often a non equilateral triangle. It’s whatever gives the best "action" when you touch the component. When pushed slightly the component should return to its original equilibrium position. When the mass and forces are all balanced out, including friction, the system is in equilibrium. It’s the same for springs, the mass should be distributed equally among the springs, so the forces are balanced out, assuring uniform mass-on-spring performance as well as perfect level of the component.
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Actually the 6 degrees of freedom is a misnomer since it’s obvious that for the horizontal plane there are an infinite number of directions, not just the two X and Z directions. Which explains why roller bearings are so effective for the horizontal and why isolation devices with multiple lateral springs like my olde Nimbus unipivot and whatever iso pod that has a bunch of lateral springs radiating outward from the center. You will also get better rotational isolation with a single spring or air spring than with multiple ones. It’s too bad you can’t get away with using a single roller bearing assembly.
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Obviously there are vibrations below the frequency speakers can deliver. Those are the seismic vibrations. Obviously it’s better to isolate the speakers along with everything else, no?
"I said this would be fun but I didn't say for who." 😃
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Tapping noise and 60 Hz noise is not why we employ isolation. Those are examples of higher frequency vibration and induced vibration. One needs to address induced noise, airborne vibration AND low frequency seismic type vibration. Even solid state amps and power supplies, .i.e., things with no moving parts or things that seem solid, should be isolated. The printed circuit boards and wires are all subject to vibration. For components with transformers on board the transformer should be isolated from everything else, especially the printed circuit boards. Bolting the transformer tightly to the chassis is probably one of the dumbest things manufacturers ever did. And they’re blissfully unaware of the issue. Or, if they are aware they dismiss it.
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Unfortunately it’s not really a question of "microphonic immunity." There is nothing you can do to make a component - any component - immune to low frequency seismic type vibration, I mean other than isolate it from those vibrations using some type of low pass mechanical filter. That’s because the entire building is shaking, so anything connected to it is shaking right along with it.
Obviously some steps can be talken (but usually aren’t) inside the component to guard against vibration with higher frequencies, you know, using damping techniques,including those produced by the component itself such as transformer hum, CD transport mechanical noise, motor noise, etc.
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Totally agree with the observation that the location of cones underneath components is a variable. By the same token, cones should always be placed under vibration isolation stands, either in sets of three or four, and those locations affect the sound, too. So, to summarize, we have the variable of cone locations underneath the component, whether the components is isolated by an isolation stand or not, AND the variable of cone locations underneath the isolation stand itself. As the previous poster points out it can take some time to sort out what the very best locations actually are, especially is there are six or more cones involved. Think of it like trying to solve six simultaneous equations in six unknowns. And finally, a big shout out for isolation devices that can isolate in more directions than the horizontal plane and vertical direction. Keep in mind that there are actually six, count em, directions of motion that are involved including three rotational directions. The horizontal plane counts as two. |
theaudiotweak
When considering any footer or point of any material in the vibrational signal path ask yourself..
Self...Does the shape geometry I am looking at provide a path for the intended dissipated energy to escape and not return or reflect back into the footer or tip?
Tom ....Star Sound Technologies
uh, Tom, are there ANY audio cones that AREN’T shaped like a cone with a tip pointed toward the bottom? The sky is blue. OH, wait! A spring is symmetrical. OMG! A Herbies footer is not pointed! Oh, no! Super Balls are not pointed! What?!
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Another vibration isolation tweak for the financially strapped audiophile - a set of three or four Super Ball and Snaple bottle cap assemblies. The Super Balls are the 1" high bouncing colored balls found in bubble gum machines. But not the larger balls.
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Bdp24, that’s an outstanding idea! It’s also what I just described. 😬 The aluminum or wood frame is a 3’ X 3’ open cube. Place the frame on Super DH Cones of course.
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One of my fav DIY isolation projects is bungee cords suspended from an aluminum frame (it could be a wood frame, too). By angling the bungee cords - one to each corner of a maple plate - you can effectively isolate in almost all 6 directions of interest. I built one of these babies for a DVD player but it could be for just about anything. Select the stiffness of the bungee cords based on the load. I got my aluminum frame at a junk metal place. Easy as pie.
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I'm not saying that at all. Everything should be isolated, power supplies, line conditioners, DACs, etc. |
Cables and power cords have no moving parts, either. Nevertheless.... |
