Damping Vibration - Friend or Foe?

the problem with the analogy of the dollar bill and the lead weight - at least for isolation of low freq. vibration - is that seismic forces are extremely powerful, so powerful that they move the entire building with ease, including everything in it, no matter how heavy. In fact the building is continuously shaken & twisted in many directions by seismic forces. Mass loading, that might be effective for damping of vibrations with higher frequencies, is not an effective means to isolate a component from very low freq. vibration circa 0-10 Hz, since the lead weight will also be moved up & down - and even rotated - by seismic forces. Therefore a different technique(s) must be used to address frequencies below 10 Hz.

Stehno, here are a couple of non-perfect, but simple analogies to help explain.

Take your cushy couch and put it in an automobile that doesn't have any shock absorbers. I bet you feel alot of vibrations no matter how thick the cushion is. Now, take that same scenario and insert some professionally engineered vibration control devices (ie. shock absorbers) in that car and I bet the level of vibrations you feel is less.

Now, for airborne vibrations, take the wind as an example. If you put a dollar bill on the street, it will likely fly away with a gust of wind. However, if you put a lead weight on top, then it's more likely to stay in place and not move at all. Again, these are simplistic and exaggerated analogies, but the basic concept is fairly obvious.

Indirectly, you bring up a good point/question. We are talking about vibrations at a much smaller magnitude. How much 'attenuation' of vibrations actually results in an audible difference in a component? I suspect it is different for each component and each type of component, so your best bet is to just buy vibration control products based on sound engineering principles.

This has been a fun and highly educational thread. I would suggest that a manufacturer can be comfortable answering a more probing question about his products by private Email, and then putting a link in the thread for anyone else wanting to see it.

This way the expertise and general discussion can continue without someone seeming overly self-promoting. I do like how this thread has evolved and I would think that it has stayed on the better side of 'the slope'. Also the disclaimer could be at the start of the opening thread so those who don't want to read it can just move along.

As far as noise and dampening, etc. I offer the following:

My Profession is Real Estate and I run my office's Property Management Division and we are located in a major metropolitan area with lots of busy streets, some quieter neighborhoods and lots of new and old construction and plenty of apartments.

I got a complaint from soneone who had just bought a new Condominium in a quieter neighborhood about noise coming from next door. Over a period of time the complaints become so strong that the neighbor was terrified of walking accross his floor in shoes and using his toilet. The complainer was getting ready to sue the developer and the Homeowner's Association for inaction.

I brought in an Engineer who specializes in noise and dampening, etc. and he performed a number of tests from the 'offending' unit to the 'impacted' unit to see what could be done. As it turns out, very little could be done as the ambient noise level in the building was so low that just about any sound whatsoever could be heard.

You should have seen everybody's face when we reported the building was too quiet! So, the neighbor's "power piss" carried next door. We did itentify a piece of sheet metal in the wall at the bathroom that we insulated and we insulated all of the wires at the switch boxes and this did help.

Also, the fellow do longer aims at the water. Oh, the complainer moved; I just wonder what she put in the Seller's Disclosure Statement..........

Because it is my intention to mechanically couple my speakers, components, and rack to the flooring system!

You are lucky enough to live in a cul-de-sac, and hence feel that vibration through the earth due to passing traffic is not an issue. You are no doubt aware that the very low frequency disturbances from large trucks etc do travel many miles before attenuation. Perhaps you are more than 20 miles from major freeways too.

As for seismic waves, the geological structures that your home is sitting on contribute to how much these waves affect your system. Deep clay beds and the like obviously transfer less energy from seismic vibrations than granite or basalt.

Regards,

The wave launch and acoustic center point of my room is aimed at my listening chair and away from my audio rack..Does not everyone listen like this? Geometric acoustic devices designed as part of my ceiling further capture frequencies and redirect them to the listener and away from the audio rack. In my system I expect by design to hear more energy at my chair and less at my audio rack..Tom

Flex, thanks for the clarification.

However, I am quite aware of all that you say. I remember about 15 years ago, a siesmologist saying with over 400,000 earthquakes registering around the world in that previous year, that the world was literally and constantly shaking and like never before. And supposedly each year it's getting worse.

But I still don't care about things like traffic, tremors, and such. And what you've described is something everybody faces. So what?

My speakers are sitting on Audio Points. My rack is also sitting on Audio Points. Oh, and my components are also sitting on Audio Points. Why? Because it is my intention to mechanically couple my speakers, components, and rack to the flooring system!

The generic term for this methodology is called coupling. BTW, can you guess what the other methodology is generically called? Decoupling! But again, I'm really not concerned with floor-borne vibrations no matter how loud or bass heavy the music is. What part of this do you not understand?

What have you done with your speakers? Are you gonna' suggest I put a sandbox under my house or kitty litter boxes under my speakers? I also live on a culde-sac and I am blocks away from the nearest thru-street.

No offense, but until now, I've not directed any statements toward you. So please feel free to change the channel if my responses to others bother you.

-IMO

Do the sitting test with ____points and tell us what you feel. Less vibrations than what?

"As for floor-borne vibrations, I personally don't even consider that much of an issue unless I had a much older home and a very, very bouncy flooring system. "

Stehno -
Unless your speakers stand on isolated rocks, they couple mechanically into your floors. Low frequencies from traffic, from seismic sources and the like couple into your entire building structure as well as the floor. Woofers direct energy at the floor (amplitude from a point source decreases with distance squared, the floor is CLOSE to your woofers). Read some of the many articles on vibration sources in sound systems, talk to a studio designer, talk to an acoustician, read Stereophile, just do some research already.

Labtec, thanks for clarifying. I did not confirm exactly what Barry stated and I certainly don't want to misquote or even misinterpret what somebody else says.

But I got the impression that Barry was addressing his products effects from a somewhat hypothetical and third person perspective.

If Barry is only saying that his products ATTEMPT to address all three, then it may still be fairly safe to assume that he has a certain level of confidence that he has done so properly and adequately.

Whether Barry has that confidence level or not really does not matter. For even if Barry claims that his products only attempt to address all three, I don't believe that I would have to change any of the questions I posed to him.

As for my example of sitting in a cushy chair. We're talking about 8 to 10 inches of foam atop of springs under my normally weighted buttocks. How much more isolation do I need? If I lift my feet off the floor I still receive what I perceive to be the near exact same level of air-borne vibrations contaminating my body. And it's my believe that it's those same vibrations to one degree or another that my components are also capturing. Again a simple test.

I don't see what's so hard to understand there. Since putting a sandbox under the chair is a bit impractical, why not put 2 or 3 cushions on top of one another and then sit cross-legged on those cushions. I haven't tried this yet, (perhaps I should) but I would venture a guess that I will still capture the near exact same air-borne vibrations. Now that would be a practical and easy test.

As for floor-borne vibrations, I personally don't even consider that much of an issue unless I had a much older home and a very, very bouncy flooring system.

-IMO

Barry what is the bandwidth of your devices? Have you calculated a refresh rate ..at what point do your devices become saturated and then impede frequencys that follow? Tom

" It is also a fact that as one sits in their cushy(well-damped) listening chair feeling the vibrations from the music, one can bet dollars to doughnuts that their equipment is feeling pretty much the same vibrations regardless of whose vibration control system products are being used."

Though there is much to say on the whole subject, the sentence above is easy to disprove - at least in my house. Place your hand on the listening couch and you feel the whole dynamic shape of the music. This is 80-90% floorborne, as you can show by placing a screen in front of the couch to block off the direct radiation (no, that won't kill ceiling or sidewall reflections which are still there). Now, place your hand on the top chassis of your gear, which in my case sits on a Grand Prix stand. Nothing to feel. In other words, the amplitude of surviving vibration is vastly lower.

I'm sure Barry can and will respond for himself, but a few thoughts...

First, I didn't read Barry's response to say his products completely protect components from "ALL vibrations".

If you read carefully, he said his products ADDRESS more than just one type of vibration and MINIMIZE (not totally remove) their effects. I think he was correct in pointing out that many vibration control products ONLY try to address one or two types of vibration. He's saying his products ATTEMPT to address all three. Whether they do or not and to what degree can be debated. However, to criticize his argument because he is attempting to address all factors seems backwards.

As for your proposed experiment, I can almost guarantee the vibrations you feel in your couch would change if you placed it on top sand box and added mass to your body. Would it totally eliminate the vibrations you feel now - probably not, but I'm sure it could remove or dissipate some of it. I'm not sure why that's so hard to understand.

Barry, I know we've touched on some of this before.

It would be wonderful if one's products addressed every aspect of a given issue. And perhaps this can be accomplished by some products in some industries. But I have my doubts that your products (or anybody else's in the audio industry) being capable of such things as you seem to be insinuating above.

Would you not agree that if your products were to properly address one type of vibration:

o say air-borne, then have you not just trapped the internally generated vibrations within?

o say floor-borne, then have you not just trapped all air-borne vibrations that continue to be captured by the components?

o say internally generated vibrations, then ..., well actually if you are making this claim for your products, I'm very curious how you think your products have accomplished this.

It is a fact that components in a music room WILL capture air-borne and floor-borne vibrations and they WILL generate their own internal vibrations. As far as I know it is physically impossible to completely protect a component from ALL vibration unless one were to remove the component far out and away from the room where the vibrations were occurring and/or the components were turned off.

It is also a fact that as one sits in their cushy(well-damped) listening chair feeling the vibrations from the music, one can bet dollars to doughnuts that their equipment is feeling pretty much the same vibrations regardless of whose vibration control system products are being used.

If you are claiming that your products have overcome this, then shouldn't I be able to use your products to also prevent my physical body from experiencing those same vibrations that are hammering my components? I would think this would be a relatively easy test.

I just don't see how anybody's vibration control system products can essentially be all things to all vibrations such as to kill them in their tracks BEFORE they contaminate the components like spraying bugs with a can of RAID.

-IMO

Hi Thomas,

Thank you for your questions.

We either own or have the ability to borrow virtually all of the commercially available vibration control devices on the market. We have also experimented with hundreds of different configurations and devices that have not made it to market as well as the DIY devices that are discussed on internet forums such as Audiogon.

I will refrain from making a critical assessment of any specific product from a competitor but I do make more generalized comments about the various technologies or materials employed and their capabilities and limitations.

Because there are a number of different sources and forms of vibration and resonance that are present in an audio and video system that affect the signal flowing through a component the most successful vibration control device will address all of them. Devices that only address one or two forms or sources are only partial solutions.

It is critical that a complete vibration control solution eliminate vibration that can affect a component BEFORE the contamination is allowed to occur. Once the signal flowing through a component is affected by vibration no amount of "draining" or "dissipating" can reinstate the original pristine condition of the signal. A vibration control device that is placed merely underneath a component CANNOT restrict contamination from air-borne and internally generated sources of vibration. Any vibration control device that couples the component to the support underneath it CANNOT protect the device from floor-borne vibration.

The most successful vibration control SYSTEM will:

1) Decouple the component from floor-borne vibration.

2) Minimize as much as possible the contamination component from air-borne vibration.

3) Minimize as much as possible the contamination component from internally generated vibration.

I strongly suggest that people critically assess the devices they are now using or are contemplating purchasing or making themselves to see if they meet the minimum criteria and do address ALL of the forms and sources of vibration and resonance. It is also critical that the devices (whether commercial products or DIY devices) do not contribute their own problems into the component. Selecting materials that ring (granite, marble, glass, stone, Corian, steel, etc) or materials that are resonant (natural wood, wood cutting boards, Plexiglas, acrylic, plastic, etc) for use as vibration control will FURTHER contaminate the signal and take us further away from faithfully reproducing the signal that is contained in the recording.

The above discussion is not a criticism of the Stllpoints or any other specific product.

Best Regards,

Barry Kohan

Barry,
Have you had any experience with Stillpoints ?
If so, what was or is your opinion on their
capabilities ? I use them under my pre-amp,
power supply, amps, and power wedge with
phenominal results to my ears.
Thanks
Thomas

Barry, thanks for the update and congratulations on the numerous awards and recognitions for your ingenuity and designs.

-IMO

Hi Albert and Stehno,

Thank you for your questions.

Albert asked: “Barry, are your sand filled boxes as good a way as any for solving the vibration problems being discussed? I am aware they are a long time product of Bright Star, very popular and often imitated by various user and DIY groups. So, what about the question about the sand filled boxes you guys build? The best way to isolate equipment, or have you come up with something you like better?”

Stehno asked: “I'm not sure if it's ever been stated. Exactly what products does Bright Star mfg'er?”

I designed and built the first Big Rock vibration control platform in 1985. My turntable at that time was Micro Seiki BL-91 which I had inside an old Victrola reproduction cabinet. I upgraded to a Micro BL-91L (transcription size) but it no longer fit inside the cabinet so I placed it on top. Unfortunately, I started to have woofer problems as the result of vibration breakthrough to the turntable - I have the large Infinity IRS speakers (completely rebuilt and heavily modified) that have very extended low frequency capability. I thought about what I could do to solve the problem so I built up the top portion of the cabinet and created a high mass, high absorption section that was filled with sand as the absorption medium. Well, not only did the woofer problems cease but the turntable sounded MUCH better!

I didn’t think too much more about it until I decided to leave my position as the general manager of a chain of high end audio stores in southern California (after almost fourteen years) and become a speaker manufacturer – I had already been designing and modifying speakers professionally for a number of years. I created a pretty innovative full-range dynamic dipole speaker, booked an exhibit room at the 1990 CES and started to put together my demo system for the show. I had previously attended CES for a number of years as a retailer and always heard the exhibitors complain about the vibration from neighboring exhibit rooms. I decided to make a few portable versions of my sand base for the display system only – not really intending to sell them. Well, the first day of the show people came into my room and said “Nice speakers – WHAT ARE THESE BASES!?” They kept doing that all day long so later that night I realized that I HAD to make a product out of it. I thought up a name, figured out how much they’d cost to make and what the retail price should be, ran out to Kinkos to print up some literature and the next day it was an official Bright Star product!

The next CES was six months later in Chicago and I brought bases for my entire display system but also brought another dozen to loan out. That year Monster Cable requested my speakers to use in their show display so I also loaned them a Big Rock platform. Additionally, I loaned platforms to some very well known and established companies like VTL, Krell, Genesis, Versa Dynamics, Von Schweikert, etc. This gave my platform some credibility so the reviewers requested them for evaluation. Well, they loved them! Stereophile nominated it for “Accessory of the Year”, The Abso!ute Sound voted it “Editor’s Choice”, Bound For Sound gave it a “Component of Merit” award, The Academy nominated it for the “Golden Note” award, Fi Magazine voted it “Editor’s Choice” among many other awards from magazines around the world. My speakers were also quite well received having a major review in Audio Magazine and reviews many other magazines around the world, plus being called “a legitimate high end Best Buy” by The Abso!ute Sound and being voted one of the “Magnificent Seven – Best Sound at the Show” in Stereophile’s 1995 CES report, but Bright Star became more well known for vibration control products. I have also been issued patents on both the Big Rock platform and the Altair speaker.

In 1991 I started to think about vibration control much more seriously and realized that floor borne vibration entering a component’s feet was not the only contaminating source. Air borne vibration striking directly into the component’s chassis from the speakers and internally generated vibration are also major sources of contamination that compromise the signal flowing through an audio system.

My vast experience researching materials over the previous ten years in connection with speaker design played a significant role in the development of the Bright Star line of vibration control products. The next model I introduced was the Little Rock (which has also won a number of design awards). It is a high mass damping pod that is designed to be placed on top of the component. The mass of the Little Rock causes the component’s chassis to be much more stiff making it much more able to repel air borne vibration and resist sympathetic resonance. In addition, the Little Rock has the ability to absorb vibration and resonance out of the component and it provides EMI (electro magnetic interference) shielding. Another benefit of the Little Rock is that is couples the component’s feet much more firmly to the top of the Big Rock so that a very efficient conduit is created to transfer unwanted stored energy (vibration and resonance) out of the component and down into the Big Rock platform where it is converted very quickly to thermal energy (heat). The Big Rock has the ability to absorb a huge amount of energy and we want as intimate a contact as possible between the component and the Big Rock to facilitate the transfer of the harmful vibration and resonance.

As impressive as the Big Rock is at absorbing a wide band of energy it did not decouple from very low frequency floor borne vibration as effectively as I knew was possible. I then created the Air Mass pneumatic mount that could be placed under the Big Rock / component / Little Rock combination. The Air Mass provides excellent decoupling of the components placed on top of it and benefits from the high mass of the BR / component / LR combination to achieve an extremely low resonance frequency. Horizontal displacement is also minimized due to the high mass and resistive inertia of the system. There are multiple sizes of each Big Rock, Little Rock and Air Mass models. The original Air Mass 1 was only $99 and could hold 99 pounds so it was an instant hit with consumers and reviewers alike. It was nominated by Stereophile for “Accessory of the Year” and voted “Product of the Year” by The Abso!ute Sound. The Air Mass / Big Rock / Little Rock combination (which we humbly call the Ultimate Isolation System) has won a number of design awards including being voted “Standout Product of the Year” by Soundstage! Bright Star also has many products listed in Stereophile’s Recommended Components. Our Ultimate Isolation System TNT, designed specifically for VPI’s TNT series turntables has been nominated for “Accessory of the Year” and was also on the cover of Stereophile’s December 1997 issue.

In 1991 I also found very few equipment racks available which were capable of holding even one of the very heavy Ultimate Isolation Systems let alone the three or four required for a full audio system. I introduced The Rack Of Gibraltar at CES 1991 which I designed to be the strongest and most rigid equipment structure available. A funny story is when I went to the welder to pick up the first prototype he asked me what it was for. I told him it was for stereo equipment. He looked at me like I was from Mars! He thought it was going to be used at a car show to support a display car up in the air because the rack was so intense and strong! We rate the large size Gibraltar racks to hold over 2000 pounds. The Gibraltar series of racks have also won a number of awards including being nominated by Stereophile for “Accessory of the Year” and voted “Best Buy” by The Abso!ute Sound.

Over the last few years we have introduced a number of much more affordable vibration control products including the IsoNode anti vibration feet which start at only $12.50 for a set of four. The IsoNode feet were just voted “Product of the Year” and were included in The Stereo Times’ and PC World’s Holiday Gift Guides (people love them under notebook computers, multimedia speakers and subwoofers, and outboard digital drives). The IsoRock 4 and IsoRock 5 platforms combine multiple layers of high mass and absorptive materials and use IsoNode feet on the underside to decouple from floor borne vibration. The Little Rock 4 and Little Rock 5 provide the mass loading benefits of the other Little Rock models but do not include EMI shielding. Our Gemini platforms combine an Air Mass and Big Rock into a single model. Any of our models can be used individually with a component but best performance is achieved when they are used in groups of two or three. In addition, speakers benefit greatly when a Big Rock is used underneath and a Little Rock is used on top. Subwoofers show phenomenal improvements with this combination.

On the other end of the scale I have created our Reference Series. These components are the ultimate expression of my philosophy of vibration control and incorporate many cutting edge materials including heat-fired glass crystal, high density polymers, polymer adhesives, carbon fiber, solid brass and many other innovations. The new IsoRock 3 Reference platform was introduced at 2004 CES to provide many of the qualities and performance capabilities of our top Reference Series models at a more affordable price.

Please let me know if you have any questions.

Best Regards,

Barry Kohan
President

Barry, nice review on the Gilmores and I appreciate your being a firm believer in 'overkill'. Also, sorry for the unexpected side-bar earlier this week.

Regarding your previous responses to my post, I would agree with you regarding the air-borne vibrations exciting the car and windows, etc.

However, I don't think I could agree with you on the ground being exciting and the transferring of those vibrations coming thru the street up thru the tires' rigid sidewalls. To the best of my knowledge, not even jackhammers or even some smaller pile drivers are capable of that kind of earth-shaking impact.

I certainly agree with your other statement "merely decoupling a component from floor-borne vibrations will not completely eliminate vibrations, .... Battling vibration effectively can only be accomplished by combining the right materials with the correct methodologies."

Again I come back to the impossible and perhaps unwanted task of eliminating all vibrations which we know cannot be done. And that is why I believe it best to expedite the transfer of those vibrations rather than try to suppress them.

Also, I have difficulty believing that the ultimate goal of those adhering to the decoupling methodology is to remove all vibration.

In your opinion, what would happen to the sonics if 'all' vibration were removed?

Thanks for sharing. And I hope you'll understand when I say I hope not all of your threads are as exciting as this one. :)

BTW, I'm not sure if it's ever been stated. Exactly what products does Bright Star mfg'er?

-IMO

Hi Albert,

Bright Star and Gilmore Audio shared three display rooms at CES and T.H.E. show in January. I had been familiar with the design for a number of months before CES and had seen one of the raw panels but had not heard the speakers before set up day.

I have been designing, building and modifying speaker systems since I was sixteen years old (I’m now forty seven) and have extensive experience with ribbons, planer-magnetic speakers, electrostatics, hybrids, dynamic speakers, line source and dipole designs. I have designed speakers professionally for over twenty years.

The presentation of Abraham Laboriel’s 5 string Yamaha bass through the Gilmore speakers at CES was exceptionally clean, well controlled, had outstanding dynamic range and I would say had the best articulation I have ever heard from a live electric bass guitar.* (I have been a professional musician – drummer – since I was sixteen years old and have heard many electric bass guitars through many different amplifiers and sound reinforcement systems. I have also played extensively in totally acoustic music ensembles and have been exposed to the sound of live, unamplified instruments in many different situations). I was present for at least ten of Abraham’s performances during the show. The subtlety and definition of each note that Abraham played was very well exhibited by the Gilmore speakers. Abraham has such amazing bass playing ability that even his 32nd notes (!) were each individually identifiable. That is a testament to his virtuosity and the speaker’s resolving power.

I have read a few posts on Audiogon and in few other sources from people who thought that the Gilmore’s bass response was not as extended as the manufacturer claims (the Model 2 Gilmore speakers are spec’d to 17 Hz) . Most of them seem to have based their comments on only a five minute session listening to Abraham playing his Yamaha bass live through the speakers. Unfortunately, this limited exposure is not representative of the speaker’s true capabilities. Abraham’s five string electric bass only extends down to slightly above 30 Hz. The instrument itself does not go lower. Unfortunately, many listeners are only exposed to live bass sound that is highly non-linear due to gross resonances in bass guitar amplifier/speaker setups, poor sound reinforcement systems and generally deaf sound engineers. Additionally, listeners who are used to bass reproduced through the vast majority of home systems have gotten accustomed to bloated bass from speakers that are not well designed and which exhibit resonances, overhang and poor integration with the room and its boundaries. The Gilmores did seem to go down quite low when a CD or LP was played through them.

The midbass, which is usually the Achilles’ heel of planer/dynamic hybrids was handled very well by both the Model 2 and Model 3 Gilmores. I did not hear obvious discontinuities or upper pass band response from the woofers that was out of proportion at the crossover point to the ribbon.

Transparency from the Gilmore speakers was also quite good and they lacked the glare and the intermodulation artifacts that plague the vast majority of planer speakers (and most dynamic speakers). I seem to be more sensitive to IM problems than many audiophiles and sound engineers. Midrange response was also quite good without exhibiting the etching and upper midrange brightness that most people describe as “detail”. The top end was also transparent and free of exaggerated brightness. Most speakers have high frequency response that is brighter than the musical instrument it is attempting to reproduce would be if both were played side by side.

Any areas of performance that were not exceptional could have been attributed to a number of conditions that are typical of show set ups: room acoustics, atmospheric conditions (dry air, over-heated rooms, too many human bodies in a small space, etc), sagging AC lines, the perennial problem of equipment that is not fully broken in before the show begins, etc. Demo material (particular recordings) used can also make a HUGE difference in people’s impressions of a show system. In addition, even though the relatively normally powered Atma-Sphere amps that were used to drive the speakers at CES did a valiant job and reached pretty good volume levels, I look forward to hearing the Gilmores with those intense MA-3 mono blocks or another mega amp that matches the speaker well. I am a firm believer in “over kill”.

My statements above are not meant to give the impression that I think the Gilmores are perfect (or any other speaker is perfect for that matter) and that there isn’t room for any potential improvement. I would have to spend much more time with them under controlled conditions to assess their ultimate capabilities. I would also like to run a number of measurements of their performance before I could make that determination.

Best,

Barry Kohan

* Abraham's playing was a mezmerizing experience. Every time I heard him play I was blown away with his virtuosity and said to myself that he couldn't possibly play any better, but amazingly enough he DID play even better the next time!

Hello Psychicanimal,

Quadruple de-ionization is a term that Garth Leerer, my main distributor and wordsmith came up with to define 4 cycles through dual bed DI tanks.

If you'd like to discuss this further, feel free to e-mail me directly so that we don't distract from the original thread topic.

Kind regards,
Brian Weitzel
Record Research Labs
[email protected]

Barry - Again, my thanks to you for sharing your time and knowledge.

Barry: Forget what i said earlier i.e. i'll keep my big mouth shut. You've obviously been asked a legit question by someone that wants an answer. Have at it. Sean
>

Hi Albert,

My impression from some of the responses I received to my thread "Can Manufacturers Post and Reply?" was that manufacturers should operate under more stringent guidelines than "civilian" Audiogon members. Do you think I'm maybe being a little too cautious?

Best,

Barry

Barry, it's getting to where your not discussing much of anything. I was supportive of your posts at Audiogon, but if none of them say anything then why are you here?

You never even answered my question about the Bright Star bases. Are you afraid to do that as well?

Hi Albert,

I don't think it's appropriate for me to discuss a specific product from another company, but I am impressed with many aspects of the Gilmore speakers especially considering my only exposure to them so far has been under show conditions.

Best,

Barry

So Barry, where's your naked female spokes person?

What's your personal impression of the Gilmores? I know what two reviewers think as well as one display room.

Hi Couvajazz,

Corian is relatively dense which, of course, makes it heavy. It is also quite stiff. On first glance it would seem that it would be a pretty good material for vibration control. Unfortunately, it is exactly those two qualities that make it inappropriate. Being rigid, it transfers vibration up from the floor into whatever is set upon it - it does not have the ability to absorb and dissipate vibration. Also, like all solid materials, Corian has a resonance frequency and it can be excited by floor-borne and air-borne vibration and exhibit ringing effects. It may not be as resonant as some other solid materials but it is far from non-resonant - even very thick pieces of Corian…or granite, or Plexiglas, or Fountainhead, or concrete, or marble, or glass, or steel, etc, etc, etc.

When used in a speaker design Corian does have interesting and potentially beneficial capabilities. Because it is rigid it can serve as a very good baffle material when incorporated into the design correctly. Two speakers that come to mind that use Corian baffles are the Genesis Model One and the new Gilmore speakers. You may note that both of these systems are dipoles and as such do not place a Corian panel in an environment where high pressure would be applied unevenly to one side of the panel versus the other as it wood in a traditional closed box design. The results in much less flexing of the Corian than it would be exhibiting in a closed box system.

There is much more that can be discussed about the use of Corian in a loudspeaker.

Best,

Barry

Disclaimer: I am a manufacturer of vibration control products and loudspeakers. In addition, it should be noted that Bright Star Audio shared display suites at CES and T.H.E. Show in January with Gilmore Audio and that a company affiliated with Gilmore is a Bright Star dealer. Genesis is not associated with Bright Star but they have used our vibration control products in their show displays at a number of audio shows.

Barry,
Re: Corian
Prior to your earlier comments, I took the heavy, rigid and inert properties of Corian to imply that it could offer some benefits towards resonance dampening. Given that you have suggested otherwise and more recently acknowledged some possible beneficial usage in speaker applications, I'd appreciate some more of your insight on it's properties and application. Thanks

Hi Couvjazz,

In my reply to you I discussed Corian. Even though I do not recommend as a vibration control material, I do think it can have some very intersting applications for speaker systems. Of course, it depends on the design of the specific speaker.

Best,

Barry

Disclaimer: I am a manufacturer of vibration control products.

Hi Ed,

>Barry...you're OK.<

Thanks. My dog seems to think so, but I'm not so sure about my wife sometimes! :-)

Best,

Barry

Bright_star_audio...The "motors" that actively damp vibration of the platform are piezo devices. The weight placed on the table does not affect its performance. There is a manual adjustment for loading, so as to get the electronic system centered within its control range. Our dish of mercury only weighed about 30 pounds so we bought a smaller model. Other models will support more. However, if there were active vibration isolation in place, the need for other massive devices would be diminished. Incidentally, it holds the table level (few arcseconds) as well as "dead". Other compliant isolation devices, including pneumatic, may have a problem in this regard.

Barry...you're OK.

Ed

Barry, I am thankful that you have iniated this thread. Although, we now know who you are, so you don't have to end every post with a disclaimer. We are pretty informal here, and are all(mostly) friends.

As someone who will be giving vibration control down the line, I am enjoying this discourse and the other one regarding rack building and materials.

Barry - Thanks for the explanation and subsequent discussion. Looks like there is more experimentation and learning left on my part. The good thing is I consider this an important source of fun in this hobby. Besides it uultimately is the basis of making an informed customer choice when its time to "buy".
As to your question on my mass loading... I placed a steel plate on a bed of rope caulk on top of the CD cover. The underside of the CD cover is also covered with Dynamat. Am I still penalized by the "ringing"?

So, basically you're saying...

ok ok OK! i DIDN'T read all the postings. the first few killed me. What happened to the usual, nonsensical diatribes that USUALLY permeate this forum...?

NO SERIOUSLY. i think i'm losing my mind.

thank you to all who care.

Forum.

A. Public meeting place for open discussion.
B. A medium of open discussion or voicing of ideas, such as a newspaper or a radio or television program.

2. A public meeting or presentation involving a discussion usually among experts and often including audience participation.

If the answer is no, perhaps we should no longer refer to these as Forums.

Eldartford,

I would suspect that in the electronic platform in your lab either the piezo elements sense vertical or horizontal displacement and feed servo motors that provide correction or possibly the piezo elements themselves are the motors.

A 60 pound load weight capability for a multi-thousand dollar platform is just barely adequate as an audiophile support because most of the components that would be placed upon it would have a good amount of weight (30 to 40 lbs) and a high mass, high absorption platform would weigh at least 40 to 60 lbs. A high mass damping pod (for the top of a component) would weigh in the 30 lb range. In addition, it may be that the weight limit of the platform is 60 lbs but its optimum operating range might be somewhat less. If we are talking about reference level turntables (VPT TNT, SOTA Millennia, Basis Debut, etc), the turntables are 100 lbs and higher and an appropriate isolation platform would weigh in the 100 to 140 lb range.

With those kind of weight levels, the quality and strength of the equipment rack then becomes a very important issue.

Barry Kohan

Disclaimer: I am a manufacturer of vibration control products.

Hi Albert,

Thank you for your reply.

Considering that a few Audiogon members (Buscis2, Tireguy and Ohlala) did voice some concern about specific commercial comments by manufacturers as being inappropriate on the Audiogon forum, I would like to get their opinion on the subject before I discuss any of my products specifically. If any other Audiogon members would like to chime in on the subject, please do so.

If I do answer Albert's question I would mention the product model by name, discuss the history of the design, mention some of the industry awards and patent it has received, how the model is positioned within the product line and its applications within an audio and video system.

Best Regards,

Barry Kohan

Disclaimer: I am a manufacturer of vibration control products.

Barry,

We've had many manufacturers, including Steve McCormack, Mike Elliott, Andy Payor, Brian and Paul Weitzel, Albert Von Schweikert, Ralph Karsten (and probably others I'm forgetting) plus countless dealers. I don't see what's different about your being included.

When a manufacturer visits a site like Audiogon we get information first hand. If that person misrepresents anything it's pretty easy to know who to blame. So far every manufacturer that's visited here has helped in one way or another (in my opinion).

Of course I'm friends with dozens of manufacturers and LOVE the people in high end audio. I wish I had one friend in photography (my REAL career) for every hundred friends I've made in audio.

I think most of the people at Audiogon like hearing from the highest source on a particular product. By that I mean that the manufacturer of his or her product should be able to answer a question equal or better than anyone else. For me, it's a welcome addition. If I disagree with an opinion, it's no worse than disagreeing with a fellow Audiogon member.

I do agree that dealers and manufacturers are better off telling everyone who they are. In the case of all the people I've mentioned, I believe they have done this nearly 100% of the time.

So, what about the question about the sand filled boxes you guys build? The best way to isolate equipment, or have you come up with something you like better?

Bright_star_audio...Thanks for the info.
The isolation table we used is not pneumatic. It is purely electronic, using piezoelectric motors. The construction is of stainless steel (nonmagnetic). The model we bought is good for a load of about 60 pounds if I remember correctly. An acoustic enclosure is an option that we did not use.

The effectiveness of this device is really astonishing. However, you raise a valid point about how it would handle vibration generated by something mounted on it. It is really intended to isolate an inert object, like a mirror, from floor vibration.

Hi Albert,

Thank you for your kind comments. I did visit the Purist Audio room during set up at CES. It was quite possibly me who you spoke with at the show.

As far as your other question is concerned, I am under the impression that I must identify myself as a manufacturer whenever I post and that it is not appropriate for me to discuss my products on the Audiogon forum. Please see my thread *Can Manufacturers Reply and Post Discussions?* at http://forum.audiogon.com/cgi-bin/fr.pl?ymisc&1078434014&openusid&zzBright_star_audio&4&5#Bright_star_audio for more on this.

Did I understand this restriction correctly?

Best,

Barry

Disclaimer: I am a manufacturer of vibration control products.

Barry, there should be a blue clickable button at the bottom of the post you want to edit that says "edit my post". As others have said, it is only available until someone else posts after your message. Then it is disabled.

Frankly I'm enjoying this. I have no objection to manufactures giving their "slant" on things. I do this all the time for the gear I love :^).

Barry, are your sand filled boxes as good a way as any for solving the vibration problems being discussed? I am aware they are a long time product of Bright Star, very popular and often imitated by various user and DIY groups.

By the way, nice job of isolation in the Purist Audio Room at CES. The rack in that room had a lot of gear in it. Someone from your company came in after lunch the day before the show opened and we had the opportunity to speak briefly.

Flex,

I tried to log out and then back in but I still can't find an EDIT option near my post.

Thanks,

Barry

Hi Flex,

To answer your question adequately would require discussion of my products and that would not be appropriate in the Audiogon forums. I will attempt to answer you in more theoretical terms.

The most important concept for understanding how vibration affects an audio system and the best methods to control it is that ENERGY IS NEVER DESTROYED, IT CAN ONLY CHANGE FORM. The energy (vibration) that is created by the various sources in an audio system doesn’t just disappear, it must go somewhere and do some work. It left uncontrolled, it will cause the chassis and the internal constituent parts to vibrate and contaminate the signal. In order to eliminate the mechanical vibration we must change its energy to a more benign form. A highly effective vibration control device will accept the mechanical vibration from the component as efficiently as possible and transform it to thermal energy (heat) as quickly as possible.

What I can say is that there are materials and methods for combining and situating the materials that will absorb energy out of the component's chassis quite efficiently and will change that mechanical vibration to thermal energy very quickly.

Using light materials that don't store energy also means that thay cannot transfer the unwanted energy out of the component very efficiently and cannot transform it to heat very well.

Best Regards,

Barry Kohan

Disclaimer: I am a manufacturer of vibration control products.

Barry,
Regarding your recommendation of high mass, high absorption material above and below the component. In general, the argument against high mass is that it stores energy, especially lower frequency energy, and releases it back into the component, thus smearing transient edges, coloring sound, and reducing dynamics. Hence the argument for the use of lightweight materials that don't store energy. Do you find it possible to locate materials that so completely burn off the vibrational energy that there is no subsequent re-release back into the component? And are such materials broadband enough, i.e. operate at very low frequencies. Is it possible for any material to prevent low frequency transmission from the floor into the component, or is your solution then aimed just at reducing the resulting component vibration?

To edit your post: log in, then go to the post. There will be a highlighted line saying 'edit my post'. After editting, log out. This works until someone else posts to the thread.

Eldart, I got the monoblocks! They seem pretty good in the vibration control department. The components are anchored around the cast chimney. Good.

Hi Eldartford,

Thank you for your question.

A well designed active (I assume you are describing an active pneumatic isolation mount) can do a good job by decoupling the device placed atop it from floor-borne vibration.

There are several limitations of the available commercial designs that preclude their use for audio (and video). The first is that most of the units available are made of steel and have steel top plates. Steel rings and can have negative electrical interaction with sensitive audio components (especially, but not exclusively, with cartridges and phono sections). Some models have stone options for the top plate but natural and artificial stone does not absorb vibration and has a tendency to ring. Some active pneumatic mounts have optional stainless steel top plates and they, at least, don't have the electrical interaction issues but still have ringing issues.

The overriding limitation of most commercially available active pneumatic mounts is that they cannot hold a large amount of weight. Your lab at work is a relatively quiet environment. Your listening room at home is not - it is being filled with high SPLs of music. The component on top of the active mount is being bombarded with large amounts of acoustic energy that is being absorbed into the chassis. In addition, the component is creating its own unwanted vibration internally (spinning motors, humming transformers, cooling fans, etc.). We want to restrict as much acoustic energy and as much internally generated vibration as possible from contaminating the signal flowing through the component. Adding high mass and high absorption above and below the component will accomplish this quite effectively but will also add considerable weight. Very few active pneumatic units can hold the weight required.

It is also interesting to note, as you stated "piers sunk deep into the ground with 2000 pound granite slabs on them" has not been very effective at eliminating vibration. This can illustrate that using mass and coupling only to try and control vibration is not adequate.

Please be more specific about how I can edit my post after its been submitted.

Barry Kohan

Disclaimer: I am a manufacturer of vibartion control products.

Bright_star_audio...You can edit until someone answers.

Disclaimer...I am a skeptic about vibration control, except for phono turntables.

At work we required an absolutely vibrationless surface to put a pool of mercury that we used to get a perfectly horizontal reflective surface for very precise optical measurements. Although we have piers sunk deep into the ground with 2000 pound granite slabs on them, vibration caused ripples in the mercury, and degraded our measurements. We tried every kind of vibration isolation, without success. Finally, we purchased an active electronic vibration isolation table. It worked very well, even sitting on the floor instead of the granite slab. The one that we bought was big and strong enough to support a turntable and cost "only" a few thousand dollars...well within the budget of many vinyl-o-philes who populate this site.

My experience suggests that such an active device would run circles around any passive devices. As a vibe expert, can you comment on the use of such devices for audio. If not why not? And why don't you do it?

Couvjazz,

Addition: I do not advocate the use of a three point mounting system. Using only three cones under a component (a popular practice) which reduces chassis "chatter" by allowing the three points to more easily define a plane so the component will sit evenly, allows two of the component's corners to dangle unsupported. This situation is not desirable since the chassis can now be much more easily excited by air-borne vibration.

Barry

Disclaimer: I am a manufacturer of vibration control products.

Question - is it possible to edit a post after it has been posted?

Barry