Vibration Air & Roller Bearings - Thanks to Barry & Warren

[brucew]

The last couple years I’ve been using plano-concave lenses for my roller bearing dishes under my DAC and pre-amp. Without vertical isolation it heightens the contrast too much in the music, so that everything is hyper-detailed but unnatural. Adding the inner tube below really balances things out, but must be careful to only put enough air to just get it off the ground or the resonant frequency is too high and messes with the music – putting the focus slightly on certain frequencies.

 

This week I decided to move the roller bearings to the speakers. Great effect on detail, textures, and soundstage, but lost the complex harmonics from well recorded piano, female voice, cymbals, etc. Not feeling that confident about an inner tube under the speakers, I put a layer of double sided foam tape under the roller cups which gave me back some but not all the harmonics. It could possibly be related to ringing in the hardened glass lenses, and the curvature seems a little steeper than desirable. I’ve ordered some lenses with a shallower curve. I may try drilling the same sizes hole in a wooden base plate and imbedding them there. Or may just spring for something commercial that does a proper job on the vertical isolation, and combine the two approaches.

[brucew]

17 hours ago, tims said:

Mind if I ask where you got the plano-concave lenses  - are they available online?

Try www.edmundoptics.com. They currently have a 50% off sale (see top) and I got 25mm plano concave uncoated lenses with a 100mm focal length (50mm radius). These seem to be a type of borosilicate glass (hardened). That's well under $10 per lens. Up to now I've been using 17mm lens with a 19mm focal length. It works pretty well, but I thought I'd benefit by a little larger size and a shallower cup (100mm Fl instead of 19mm). I also saw some pyrex plano concaves on Ebay last week. 2.0" diameter and 150mm focal length.

 

15 hours ago, Solstice380 said:

I work in the vibration arena industrially and I’ll have some interesting measurements completed in the next week on these lenses and various cones, etc.  Both the natural resonances and through transmission will be evaluated.  I also have  steel and ceramic balls I’ll look at. 

I'll be interested to see what you come up with. I'm looking at drilling a 25mm forstner hole partway into a bamboo cutting board and sinking the lens into it with the tops just below the board surface. That should help damp the glass and also give an extra lip to make the ball less likely to pop out if I move the component ham-fistedly.

 

14 hours ago, GUTB said:

I believe the Symposium Rollerblocks are the only game in town for ball bearing style isolation due to thier tight tolerance and thier constrained layer construction. 

That's a pretty strong statement. Ingress Audio Engineering offer a quite reasonable price on well manufactured roller bearings. Though, no vertical isolation. I'd like to know how effective the constrained layer effort is on Symposium's roller blocks. They charge for them like it's a whole sheet, when it looks like just a couple square inches. My inner tubes work great in combo with roller bearings under a component, hard to beat if the isolation if not putting too much air in there.

[brucew]

11 minutes ago, lmitche said:

There are some innovative antivibration solutions here:

 

http://taikoaudio.com/products/taiko-audio-tana/

What a deal! They cost 0.00 on Taiko's site.

[brucew]

11 hours ago, Solstice380 said:

 

What size are your balls?  Hahaha, the isolator ones.  And where did you source them?

I use 10mm (3/8"). Check out grade 100 or grade 10 hardened. Cheap as chips and really show off what roller bearings can do. Then you can later tweak with exotic bearings if you like what you hear and want just slightly more of it.

4 hours ago, Solstice380 said:

 

I like that idea.  If you use a cup on top and bottom they are a pain to align, also. 

I don't much see the sense in an upper cup. The bottom of most components work just fine, and don;t have alignment problems. If the bottom is too soft or too rough, I just glue a metal knockout disc (from an electrical junction box) at the alignment points on the bottom of the component. Works fine and cheaper than chips.

4 hours ago, Solstice380 said:

 

To me, this is the key - vertical direction.... I use the Herbie’s to address the vertical.... We’ll keep working through this because I’m not up for, and don’t have space for, inner tubes under everything!

I've been considering Herbie's Fat Dots under the cups, but they are dampening devices as much or more than isolating devices -- wondering how effective between speakers and sprung wooden floor. I've been looking at Isoacoustics Iso-Pucks or Oreas. They get great reviews and aren't as fiddly as inner tubes, though they are 1.25" high.

[brucew]

15 hours ago, Solstice380 said:

Dont get confused about isolating and dampening.  You’d be surprised at how stiff Herbie’s dBNeutralizer material actually is. 

Yes, I get the difference and have heard about the stiffness of the dBNeutralizer. Since the Herbie's website specifically recommend to put the Big Fat Dots right up against the component case as more effective than having anything else in between,  I asked Steve if that implied that it has an important dampening effect as well... to which he agreed.

[brucew]

I do find it hard to get my head around he idea that a 'stiff' material can actually isolate throughout the musical frequency spectrum down to well below 20Hz. Whether Herbie's products do or not, they do seem to be rated as more frequency-neutral than much that is out there.

[brucew]

1 hour ago, Ralf11 said:

This is a diagram of what product, what are the dimensions, and is the bladder pressure adjustable?

[brucew]

15 hours ago, look&listen said:

New thing to talk about - Pneupod

Aside from the crazy pricing, I see that the quasi-technical bit shows scopes of vibration reduction but doesn't bother to say what frequencies. So it tells us very little. Air bladders have to be at VERY low inflation pressure in order to isolate down to below 20Hz, and low volume air bladders will make that more difficult. So... one wonders.

[brucew]

15 hours ago, Solstice380 said:

 

Those are the type I referred to in the Barry D. thread.  Inflation adjustable.  Just make sure you get the valve stems and stuff you need.  

Have you tried these McMaster's? They look like they could work, are large enough they'd need to be used on a full sized shelf, kept at pretty low PSI... yet a set of 3-4 are nearly as expensive as a lot of commercial anti-vibration shelves. Do they work well in home audio applications? And do they tend to lose air over a week's time like a lot of air bladders do?

[brucew]

2 hours ago, Johnseye said:

 

That's a great idea.  Needs some weight though to squish a racquetball like that.

Over here squash balls are easily found in three levels of softness. Still getting the resonant frequency into the single digits needs some care and weight. 

[brucew]

8 minutes ago, Solstice380 said:

 

Why do you think it needs to be in the single digits?   

There's lot of discussion in this topic and the others related to roller bearings and air bearings and the resonant frequency and its relation to isolation effectiveness.

[brucew]

17 hours ago, Solstice380 said:

 

I've read it all.  Still nobody has a real reason why they want that.  Maybe for turntables and speakers, but everything in between does in no way need that.  A lot of wasted effort to try to get it.  Any idea what 10 Hz would do to a DAC?  Absolutely nothing.

Are you questioning why vibration control is needed for a DAC or preamp; or are you asking why those down below 10Hz?

[brucew]

2 hours ago, Solstice380 said:

 

Sorry it wasn't clear... why below 10Hz?  Phase noise in clocks?

In regards to the <10Hz in general, I thought I had read that isolation is best when isolating at a frequency at least 2.5 times the resonant frequency. Isolation being a frequency curve at the edges rather than something binary. I can't vouch for it's truth. That's just what I think was said.

 

As to DAC's and preamps and 10Hz, my experience is that much effects the SQ in regards to isolation and dampening: choice of footers, coupling vs decoupling, roller bearings and inner tubes, bitumen sheets or weights on lid, nylon vs. brass PCB standoffs, etc. All these bring a noticeable effect, though more subtle than on speakers.

 

Choice of materials brings difference in effect, which I put down to certain dampening materials moving the resonant frequency of the component case, or certain coupling materials setting a different resonant / centre frequency for the coupling. If those explanations are roughly correct, then somehow analogue electronic implementations react to vibration in the musical frequency spectrum. Therefore, ideally we would want isolation throughout the musical spectrum in order to best address vibration... regardless of whether communicated from air, ground, mains input, or generated in the component itself.

[brucew]

12 hours ago, Ralf11 said:

https://techxplore.com/news/2018-04-d-metamaterials-vibration.html?utm_source=menu&utm_medium=link&utm_campaign=item-menu

Amazing! It seems that this geometric solution is frequency specific, though I wonder how narrow band the devices actually are. So it would be interesting if someone could devise a broad spectrum solution for frequency isolation, perhaps through a certain combination of devices each tuned to different frequency ranges. Also, I don't immediately see the application of "state switching" to home Hi-Fi.

[brucew]

6 hours ago, Ralf11 said:

...about the Symposium product and the internal construction of the Al block.  If they did use a hollow "case" construction then I am curious as to why. 

Symposium provides a description of what they did with the honeycomb matrix and what it accomplished for them. www.symposiumusa.com/rollerblocks.html

[brucew]

19 minutes ago, Ralf11 said:

Their verbiage makes no sense to me

 

I found a pic of the bottom - the holes are uniform in layout, not random

Can't help you with the verbiage making sense.

 

The pic was at the top of the page I linked to. Their description does not say the holes are randomly spaced but are irreguarly shaped, which implies they are not drilled and either have multiple tapers or the holes are not straight.

 

The former is more likely, because I don't imagine one can 3D print aluminum. So the holes have to be accomplished by CNC tools accessing from outside. I guess I'm not really bothered about trying to figure it, let alone duplicate it. Whether it's worth doing or not... someone should buy a set a compare to an Ingress Engineering set or similar and see if there is a significant difference to warrant the cost/design.

[brucew]

Roller bearings inlaid into a bamboo board.

Ikea Aptitlig & Edmund PCV lens 25mm OD x 100mm FL

 

[brucew]

BTW: I note that considerations of the hardness and smoothness of the bearings and cup is of rather limited value if one doesn't look at the top surface as well (the surface of the preamp, speaker, etc.) The above bearings started rolling less effortlessly and I noticed dents in the wood surface. Or what if the base of the preamp or other component has a textured surface? I found these 1" stainless steel discs on eBay. Impressively the edge is nicely finished and the surface is polished even though the description does not specifically say that. I've stuck them to the bottom of my speakers with a Glu Dot by Blutack. Solved.