Damping Vibration - Friend or Foe?

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
recres@msn.com

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!

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

-IMO