Unfortunately John, your "short" story does little for the arguement between dampening vs. coupling, both of which I do in my system, sometimes at the same time. An example of this would be my Sunfire TG3 processor. I have your Isonodes under the glass plate that comes with the Sunfire but have the processor coupled to the glass plate via cones. If I had to choose between the two, I'd say that cones have given me the best results with a sharper, more defined sound. I was really hoping for more of a stand for dampening (that would be backed with a little knowledge) after your post in the other thread. Besides, I hate to be reminded of a story that I've already lived. LOL Regards, Robin
Damping Vibration - Friend or Foe?
Hi All,
I have been reading many discussions regarding the use of damping in and around audio components here on Audiogon. I thought that the following discussion from the FAQ page of my company’s website would add a little clarity. The example here involves a home theater system but the same principles hold true for an audio only system.
Question: Some people claim that adding damping to components to control vibration can sometimes make them sound less dynamic and somewhat lifeless. Why should this be so when damping reduces the problems of vibration and resonance?
Answer: I have also heard the same comments a number of times. Unfortunately, people mistakenly attribute these negative changes in performance solely to the addition of damping to a component. If we look at the entire evolution of an audio or video system we can gain a much more clear understanding of what is happening and why it is happening.
Let’s say that John, who is an audio and video enthusiast, decides to put together a really nice home theater system. He reads a number of magazines, visits websites devoted to these topics and assembles a system composed of many highly rated components. John sits down to enjoy a well produced action movie but a few minutes into the first scene realizes that he’s not hearing or seeing what’s been described in the magazines by the reviewers. The highs are bright and harsh, the midrange is forward and the bass is bloated and ill defined. The video picture is also disappointing – the images are not very sharp or detailed, it looks rather two dimensional and the color is only so-so. What’s going on? These are all really good and pretty expensive components!
John decides to try different interconnect and speaker cables to deal with the audio problems. After two or three weeks of trying a number of different brands he decides on Brand X between the converter and the surround processor (it had the smoothest highs) Brand Y between the processor and the amplifiers (it had the best midrange) and Brand Z to the subwoofer (it had much better bass). In addition, he spent a many hours trying different speaker positions. It also happened that the cable between the DVD player and the video projector John chose was from Brand X - it reduced many of the video problems he was seeing. He then had a technician come out and recalibrate the projector for this new cable. Now John is happier with the system, after all, he even switched the front amp for a different brand. But after a few weeks he is still noticing that the highs have sibilance during loud passages, are still kind of bright, and the midrange, although better than before, still honks a little and is not that distinct on complex dialog. Plus imaging is good but not great. The bass is better but he’s had to try the subwoofer in nine or ten different positions and, of course, the one that sounded best was right in the middle of the walkway!
John is bummed but starts thinking about acoustical treatment for his room and decides that adding some of that will surely make the system sound great. He borrows a bunch of different devices from a number of dealers and spends all day and night Saturday and Sunday trying all of the devices in different combinations and positions. By 11:59 P.M. on Sunday night he’s finally found the best compromise that takes care of many of the other audio problems, although some still remain.
All this work has left John exhausted but happy for a couple of months. He can now at least enjoy watching movies but increasingly is annoyed by the remaining audio and video problems. Over time he’s also noticed some new problems he hadn’t noticed before!
Well, now what? John does more reading. He’s read about vibration control before but now starts to think more seriously about it. He knows that Brand B’s products (high-mass and high-absorption damping devices) get great reviews and have won lots of awards so he decides to try them. He places a compliant decoupling platform on the shelf, a high-mass and high-absorption isolation platform on top of the compliant platform, the DVD player on top of the high-mass platform and a high-mass damping pod on top of the DVD player and the surround processor. Well just about all of the remaining audio and video problems are now gone – the highs are very smooth, the midrange is clear and the bass is much tighter, the video picture is far better – but somehow things sound constricted and lifeless. John likes the improvements but is not very sure that this is good thing overall.
What is really going on? As we’ve seen, John has taken a fairly convoluted road to reach the point of trying the damping products. Along the way he has made many choices of associated components, accessories and set-up to optimize the system. “Optimize“ has mostly meant reducing obvious and subtle problems and enhancing certain other aspects of performance. Unfortunately, much of this effort has been an attempt to reduce the negative audio and video artifacts of vibration contamination. The choice of cables, acoustic treatment devices, speaker position, etc. have all been made to ameliorate the SYMPTOMS, not the CAUSE of the problem – vibration! Once the cause of the problem is eliminated, the system shows itself for what it is – a system where the highs and mids have been pushed down in level and dynamic range because of acoustical treatment devices and associated components, where imaging has been manipulated by speaker position and acoustic treatment to compensate for random out-of-phase elements, where subwoofer position has been chosen as a compromise, where video calibration and associated components have been selected to compensate for vibration induced jitter and other artifacts in the video bitstream, etc., etc., etc. It is no wonder that John was under-whelmed when he added the damping devices!!
Also at issue is the fact that the designers of the components in the system have voiced their designs with vibration (most probably) present in their reference systems. They have compensated for the problems introduced by vibration and resonance by changing parts and topology to minimize the symptoms (not the cause) of that problem. It is quite possible that effectively eliminating vibration and resonance with damping is letting you REALLY hear how the component has been designed.
It is often the case that the choice of set-up, associated components, ancillary accessories, acoustic treatment, etc. has to be significantly and fundamentally reevaluated when adding devices that eliminate basic problems in a system – especially problems that are as pervasive and permeating as those brought about by unwanted vibration and resonance.
Best Regards,
Barry Kohan
Disclaimer: I am a manufacturer of vibration control products.
88 responses Add your response
Hi Peacefrog, Thank you for your question. I would expect that we all agree that vibration alters the signal and that has an audible effect on the performance of a component. If we are attempting to reproduce the information that is contained in the recording as accurately as possible, any fundamental problems which affect the system which is processing the recording's information should be addressed at the outset (most audiophiles seem to address them after the fact). The three most important problem areas are: 1) Vibration Control - My views on vibration control are well explained on my website (I can restate them here if you wish). Eliminating all vestiges of vibration contamination will ensure that the fragile frequency / amplitude / phase relationship that is contained in the recording remains undisturbed. 2) AC line quality - The AC lines should have as much current as possible delivered to the outlets, the grounding should be as stable as possible, the AC energy itself should be as clean and ripple free as possible and all constituant parts (wire, outlets, breakers, etc.) should be as high quality as possible. 3) Room Acoustics - A room's acoustic should provide absorptive/reflective surfaces as uniform as possible over the entire frequency and amplitude range. This will ensure that the fragile frequency / amplitude / phase relationship of the wavelaunch that eminates from the speakers remains undisturbed. Once these fundamental areas are addressed, you can then really make accurate value judgements on the performance of the components which comprise the system. Best, Barry Kohan Disclaimer: I am a manufacturer of vibration control products. |
Thanks for the response Barry. I've just recently become interested in vibration and power issues because I just moved into a 75-year-old house, and the system is in a second floor room with hard wood floors. I know the floor vibrates easily and that this vibration is being transmitted to my gear. Question is, will I be able to hear a difference given the mid-fi gear that I have? I also expect that I have some power issues since the wiring is also 75 years old and is ungrounded. I would love to upgrade the wiring, but it's just not feasible right now. But an inexpensive power conditioner is do-able. Again, is it worth the bother? |
Barry, I wholeheartedly agree that vibration handling, electrical, and room acoustics are, in and of themselves, all very critical areas that should be proactively addressed individually. As properly addressing these items can translate to a real improvement in one's musical experience. However, in your post above, you made the following statement: "Eliminating all vestiges of vibration contamination will ensure that the fragile frequency / amplitude / phase relationship that is contained in the recording remains undisturbed." This is difficult for me to comprehend because it is my understanding that it is simply impossible for vibrations and resonance to not disturb the components, rack, and speakers unless these items were placed one or two rooms away from the listening room. My own little home-grown analogy for lack of one's ability to eliminate vibration via dampening and/or isolation is the following: "You're in your vehicle at a stoplight. Somebody three cars behind you pulls up with his subwoofer blasting. You feel the beat in your sternum and gut. You look in your rearview mirror to catch a glimpse of the guy 3 cars back and your rearview mirror is really vibrating." But the question is, Why? If the other guy's car is sitting on rubber air-filled radial tires and yours is too, and you are sitting on a well-cushioned seats and your rubber-surround windows are rolled up, why are you not completed isolated from these vibrations? Why not your rearview mirror? Now imagine how much worse that guy's chest and rearview mirror are vibrating. Should not these air-filled radial tires and the space distance between the vehicles be deemed an excellent means of dampening and isolating vibrations? Using that analogy and it's real effects as an example, I would conclude that it is simply impossible to 'eliminate all vestiges of vibration contamination' as you put it. That, and the results of my limited experiments, are why I believe it is best to expedite the transfer of these nasties away from the components, rack, and speakers via the coupling methodology. That is in contrast to simply de-couple and hence trap those vibrations inside each component and thus potentially reeking havoc on the innards and subsequent sonics. Please correct me if I am wrong. -IMO |
Peacefrog is this your 75 year old house? If it is then spend your money on a properly installed dedicated ac line using 10 ga.copper with isolated grounds and quality ac outlets..A power conditioner may be in your case like putting a band-aid on a severed hand..It all comes from the power company thru their line and to your hi-fi on YOUR LINE..2 to 3 hundred dollars should take care of the line..At my home on my system I found all power conditioning to be a negative----not a positive+++Tom..Ps direct coupling sounds the best to me..I side with Stehno. Dampening kills the music.. |
On the car thing... Your tires will decouple/isolate you only until their resonant frequency point is hit, once the resonant frequency point is hit, frequencies below that point will be coupled, Now when that SUV with the double subs and the butt kicker starts transmitting very low frequencies, below his tires resonant frequency point the sound couples to the road through his tires and then when that low frequency vibrations from the road hits your tires,the frequencies below your tires resonant frequency point couples and shake your car. Clear as vodka? Dave |
Depends on the Vodka! Kidding. I am of the dampening side of things. I use an air bladder but it has a base filled with a mixture of sand and used lead shot so that the little bee bee's don't all fall to the bottom. I also use a silicon gel that helps reduce vibration inside the air bladder. I know a friend who uses MDF with plactic cups underneath with squash or raquest balls and he swears that he feels no vibration. BUT I do use spikes under my speakers, never tried any thing else so I don't know how speaker dampening would compare. Happy Listening. |
So the air pressure we feel sitting next to or some distance away from the spl mobile can be decoupled from the chest pounding and bladder bouncing we are taking..How? Anymore than our 10k dac and transport will take the same spl pounding from our in room spl generating machines..How? Dampening only slows the release of the obvious happenstance..Why add to the injury by delaying the release of the energy.. More time and transient energy smear, more negative influence on the electromechanical devices we paid dearly for and are so eager to protect from outside pollution....results in lower efficiency and lower resolution..We just now gave all the crap more time to change the music..Tom |
Sheesh. Maybe i was wrong about manufacturers "contributing" on these forums. I can see if someone asked questions pertaining to a subject that they are familiar with or their product line, but starting their own thread about products that they manufacture and then directing consumers to their website for further info is a bit too blatant for me. How about we just have all the various manufacturers that produce "vibration related equipment" step into the ring and start swinging? After each participant gets done presenting their side of the debate and all the others get to pick them apart one by one, we'll see who's still standing. That is, if any of them are. My guess is that we would have nothing but a bloody mess to deal with and very little resolved. Sean > PS... Duke, Bob, etc... My hat goes off to you guys. You obviously have a LOT more "self-control" than some others in the industry. |
Hi Sean, I certainly apologize to you and anyone else who may have an issue with my post. My initial queery about whether manufacturers are able to post or reply was done in an up front and self-disclosing manner. My post above about vibration damping was done with that same intent. Being one of the pioneering manufacturers of vibration control products for almost fifteen years I do have a strong viewpoint about the proper application of vibration control and why some people have had negative experiences when applying damping products within their systems. I felt that my initiating a post on the subject was much more suitable than trying to "sneek in" my thoughts within the context of someone else's initial post. If the majority of Audiogon participants would like me to ask the moderators to delete my thread, I would be happy to comply. I welcome your thoughts. Best Regards, Barry Kohan |
Barry, Now you did it. You went and made Sean angree. Do you know what Sean did to the last mfg'er that made him angree? Just ask the folks around here or at Legacy. It was not pretty. {I shudder just thinking about it}. Well, Barry, it's, um, been nice, um, chatting with you but I really, uh, must go now. -IMO |
I'm just relieved that your resonance studies are not based on string theory (hehe). Personally, I hope you stay around some Barry and educate us. Resonance is a fascinating subject and touches every part of audio. Take the time to get into some posts and give us some theory. I was hoping you would jump in the Granite vs Wood audio racks thread that has been up since you have been around. thread here Some of the folks who might not be impressed if you copy portions of your site in a thread might be if you clear up some misunderstanding we share concerning materials and such. Sean can be tough sometimes but he is fair and has admitted several times when he was wrong. Sincerely I remain, |
Barry, What it all boils down to, for me anyway, is whether your presence here is merely to sell your products or to seriously participate in discussions about resonance control in a forthright and unbiased manner withour regard to whether or not the discussions involve your products or the products of others. Since you have posted about resonance control perhaps you could comment about resonance amplitude. I've read much about resonance control based on theory in these forums, but I read very little about amplitude of the resonance, i.e. how much amplitude must there be before it starts to affect the output of a devise & how can you tell when you have reached that level. I assume that this must differ for all components - certainly it would be greatly different between a TT and an amplifier. Does a manufacturer take this into consideration when designing his products? Am I out in left field on this issue? |
So what set of guidelines *would* be acceptable for a manufacturer who wants to discuss theory/practice here? This is becoming a damned if you do/damned if you don't situation. I'd far rather hear from people who've spent years thinking about (measuring!) these issues than just hearing from diy'ers and Agon'ers. A manufacturer reading Agon likely considers many discussions here to be pure lunacy, but it takes guts to figure out how to interact with the locals. Barry's posts are as upfront as any, and he seems willing to take on opposing theories. If you post links to your website for purposes of a specific discussion, cited as such, because you've already got long explanations written, I can't see the harm. |
Hi Peacefrog, Placing an audio system on a suspended wood floor does pose a number of challanges. Conversely, an audio system placed on a concrete slab also has its own set of challanges and is not neccessarilly "better" than the wood floor if the parameters are not understood well and taken into account. Getting the AC right, or at least much better than it is presently, will allow you to hear more of the true capabilities of your equipment. I agree with Theaudiotweak that your budget may be better spent on a new AC line (or at least adding grounding to your existing line). Doing the AC work may be less expensive than you think. Barry Disclaimer: I am a manufacturer of vibration control products. |
Hi Eldartford, While it is true that many users of my products do report long lasting erections, I was instructed by Audiogon members to include the disclaimer on my posts. Please see the thread "Can manufacturers post replies and discussions?". Best, Barry Disclaimer: Reading any of my posts may result in long lasting erections or $30,000,000 being transferred into your bank account from Nigeria (your choice). |
Eldartford, I am not aware of the "E.D. medication," for the "promotional tool" (not enough TV watching, I guess) do you have a web address for it? If a person says right away...bam!..."I am a dealer/seller" then let him write whatever he wants (hopefully, it will be a learned opinion). It's up (sorry, no pun intended) to each member to bite or not. In fact, I am a bit more skeptical of products when they are flung at me. As far as vibrators, I think waiting until you are married is the only... Sorry, vibrations. Although it took a longer (and more expensive) pre-to-amps run of Pure Note XLRs, putting the front gear as far away from the speakers (9 meters and behind a corner) was the ultimate problem solver. Everything improved! Seeing (read: drooling) Albert Porter's set-up helped convince me that it was, probably, the best way for me to go. My pre and transport remotes, for some reason, work just fine even at the distance between listening position and rack. (I am not using any remote extension devices.) |
Stehno: Rather than drag this thread further off topic and double posting, can you please look at and respond to my comments / questions in another thread? This post was made as a rebuttal to your previous comments concering me up above. I don't know if you were aware of this post or not, but for your convenience, i've included a link to it right here. Sean > |
threadous _postous_interruptous Golly, Sean. Are you calling me out? I mean, I've seen you take far greater punches than my silly little comment last evening. I guess that's why I find it somewhat strange that you have singled out my comment about Barry at Bright-Star making you angry and what you attempted to do to the last company who made you angry. But I really haven't had any desire to engage in a debate with you. Especially in such a formal manner as this, . . . in not one but two threads. What about the guy who deemed you an 'Internet-bully'? Why don't you call that guy out? Obviously, his statement was much more hurtful than mine. Wasn't it? Or how about the others that have apparently called you names? I've not done such a thing. Yet just because I see things from a different perspective. I mean is this not the generation that is to celebrate diversity? You know, this could be an A'gon first? What are the rules of engagement (no punches below the belt, no eye gouging, no wedgies, no scratching, etc.)? What is the ultimate purpose/goal (does the loser have to leave the planet, or just listen to the winner's system for a day, (the real question is which of those options is worse))? I suppose it could be kinda' fun. Nevertheless, I shall respectfully decline your offer to engage in meaningful dialogue or to formalize a mock trial of sorts in these parts simply based on my rather silly comment last evening. That is, unless of course you insist... Hey, wait a minute. Are you doing this just because I mentioned your owning Carver equipment in that Legacy thread you started last December? You know, the one where you showed utter disdain and contempt for Legacy the company and for Paul Bolin the Legacy speaker reviewer and for anybody who owned Legacy speakers? You know, the thread which had since been pulled? Or is it because in that same thread you kept crying uncle when others were beating up on you and I told you to get back in there and fight and I'll let you know when you've had enough? Shoot! I've forgotten all about that. Why can't you? Then again, I suppose if I were provoked... Well, I guess I'd have no choice but to defend myself at that point. Even if this is just a hobby. -IMO |
From a manufacturers standpoint, I know that I'm very careful about what I say and how I say it. Most manufacturers avoid it altogether to avoid the conflict, which is a shame. For what it's worth, I've talked to Barry at the various trade shows since 1992 and can tell you that he isn't the type to come here for self promotion. There are those who would, but not him. Disclaimer: I'm not best of friends with Barry. In fact, I doubt he could pick me out of a crowd. I do not use, nor have I ever used any of his products. I have no response about 4 hour erections. Brian Weitzel Record Research Labs |
Hi Stehno, If we know that vibration alters the signal flowing through a component we must endeavor to eliminate as much of the vibration as possible with full elimination being our ultimate goal. It is true that there are not ANY vibration control products from ANY company that are presently able to eliminate all destructive vibration - although we have prototype units in our lab that come relatively very close. In the future we (the collective “we” in the audio community) will be able to attain that goal through further research and development. But even though we do not yet have that ultimate capability we should resist the urge to go down compromised paths such as the misguided notion of “tuning” vibration. We must also reassess our present methodologies and determine if they are adequate to the task or if they only achieve partial success - such as the attempt to “drain” vibration. In the here and now, eliminating as much vibration as possible – and minimizing the amount of vibration being allowed to affect the components in the first place – should be the goal. As far as the car stereo question is concerned: What you are experiencing in your car which is a number of cars ahead of the “boom box” vehicle is: 1) vibration that is being directly coupled through the ground, 2) air-borne vibration that is sent directly from the offending vehicle and 3) resonances in your car that are being activated. The woofers in the “boom box” car stereo have been shoehorned onto a cabinet and vehicle interior that are far too small for the Thiele/Small parameters of the driver. This results in a system “Q” than is far higher than appropriate and a severely disproportionate amount of low frequency energy (but let’s also not forget about the bank of EQs that have all of the low frequency sliders pushed up to maximum!). The low frequencies have a lot of energy behind them and easily travel the distance through the air from that vehicle to your vehicle (the air in between the vehicles cannot absorb all of that energy plus the ground is being excited by the air-borne low frequency energy which is added to the directly-coupled waves traveling towards your vehicle). They also excite the windows, metal panels and plastic parts of your vehicle and cause them to resonate. Because you are in physical contact with your car, you will experience a visceral response which can be physically uncomfortable. Even though both vehicles are on air filled tires, the tires have been designed and optimized to support a heavy vehicle traveling down a road and not necessarily to make audiophiles in the car happy. The tire walls are thick and rigid plus the air pressure in the tire is too high to provide effective isolation from the audio frequencies. If you didn’t have to actually drive the car you could deflate the tires as much as possible without having them “bottom out” and achieve a much more effective level of vibration isolation. Best Regards, Barry Kohan Disclaimer: I am a manufacturer of vibration control products. |
Stehno: I had no recollection of the "Carver/Sunfire incident". It therefore never entered my mind. I'm not embarrassed in the least about owning Sunfire gear or having built my HT system around two of Bob's "Signature" series power amps and his Pre / Pro. As far as that goes, Bob's power amps have always been better than his preamps. To put the power amps in perspective, they typically offer great bang for the buck in terms of sheer brute force but lack the refinement of some higher end products. Due to their power potential though, these amps can sometimes sound "better" than more refined designs. Due to the lack of stress they undergo when driving insensitive or highly reactive loads, they maintain a more "liquid" presentation rather than get hard and grainy as things get louder. It is in these situations that they truly do their best and when i'll recommend them. I don't think that they are the most resolving amp at lower levels and there are better amps available for that. Then again, most people that listen at low levels and / or use highly efficient speakers probably wouldn't be looking to purchase a multi-hundred watt amplifier. As far as my comments pertaining to the lesser quality of his preamps, the Sunfire TG II Pre / Pro was purchased for ease of use and the fact that it has analogue pass through and a phono stage built in. The fact that it matched cosmetically made my girlfriend happy too. There are probably better products on the market, but none that i could afford with all the features / simplicity that i and my girlfriend were looking for. While i do feel that this unit is a bit of a compromise, i've more than stated my thoughts publicly about how to get the best out of it in other threads. Running it in balanced / xlr mode is a worthwhile move though. Back to the matter at hand, what did enter my mind is that you were upset with me. I assumed that this was for several reasons and this is why you were going out of your way to attack me publicly. I don't know if this had to do with our private conversations pertaining to your rack design, your HT processor or the fact that you own Sistrum products, which i've publicly criticized. There are obviously several factors here, but i don't know if any of them pertain to why this happened. As far as choosing to respond to you rather than the other party, i don't think they went out of their way to mention names, yet you did. The fact that you are a very regular contributor to these forums and they aren't was also a factor. Given that i would rather make progress in discussions rather than make enemies, i was trying to find out what your motivations were and at the same time, justify the position that i had taken. If others could see both sides of the story / were aware of the facts and felt that i was wrong in my response to you ( or anyone else for that matter ), then i would have obviously had to re-eximine things from another perspective and apologize. Given that we as individuals tend to see each situation from a particular slant, i wanted to know if i was off-base in ANY of my actions. Obviously, the more people familiar with all the "evidence", the wider the perspective / response available to both of us. Having said that, i'm sorry that it has come to something like this. I didn't mean to come across the way that i did. Obviously, there are more than a few folks that feel i over-step my boundaries on a regular basis. I probably do. For that i do apologize to everyone involved. I'll try to restrain myself in the future. In the mean-time, i've got a ton of projects to do and the weather is finally starting to break. This is a perfect opportunity for me to get things done and give all of you a break from me. Best wishes to all and i'm sorry for turning Agon into a "soap opera". Talk to you soon and hopefully under better, more friendly conditions : ) Sean > |
Stehno, I'd like to also add that merely decoupling a component from floor-borne vibration will not completely eliminate vibration. Nor will only damping the component achieve the goal. Battling vibration effectively can only be accomplished by combining the right materials with the correct methodologies. Best, Barry Discalimer: I am a manufacturer of vibration control products. |
Here is a combination that I have recently come to by chance, with very good results. I am a willing experimenter by nature, but very inexperienced in this field. Now, I’d like to understand why this combination sounds so favorable to me, I am at a loss explain it. Does anyone care to volunteer an explanation of what’s at work here? Here goes… My DVD/CD player which is dampened fairly significantly and mass loaded, sits on a platform that includes from top to bottom (top providing contact with the DVD/CD): - Ivory (using a set of 3 - picked up “selling out” napkin holders made of ivory) - Corian ( 1” thick cutting board - another “sell out” item) - Superballs (3 halves) - MDF shelf The ivory turned out to be the key component in achieving “vibration dampening as friend" bliss. The result is a clearly discernable improvement in resolution across the spectrum of high to low frequencies. It’s very musical. |
Hi Couvjazz, The interface between the component and whatever is placed beneath it is critical. Whatever is placed there has its own resonance frequency and depending on its size and mass will change the resonance frequency of the component. The superballs have the ability to absorb vibration because they are compliant but the MDF, corian and ivory do not. The initial application of the superballs is to decouple from floor-borne vibration but they will also absorb vibration from the structure above. Considering you have mass loaded the component's chassis, it is now much less resonant and is more stiff so it will not vibrate in sympathy with the air-borne vibration to the same degree. Corian, when used a vibration control material has a number of limitations. It does, however, have the ability to transfer vibration because it is rigid. Before adding the ivory rings the feet of the component were directly receiving any ringing the coriam sheet had been exhibiting. Lifting the component away from the corian by the rigid napkin holders reduced the transer of problems from the corian while still allowing unwanted stored energy (vibration and resonance) to transfer out of the component. Even though you are now pleased with your results so far, and I'm glad that you are, there is much you can do to improve things further with the use of higher maass and higher absorption beneath the component and better decoupling from floor borne vibration (you haven't really described the mass loading on top of the component so I can't comment on that). Best Regards, Barry Kohan Disclaimer: I am a manufacturer of vibration control products. |
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. |
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? |
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. |
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. |
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. |
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. |
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. |
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. |
