I use a Symposium Segue absorption platform in conjunction with brass cones to isolate and drain vibrations from my turntable. Symposium Acoustics: Products
I wouldn't go that thick and you probably don't need it to be 4". 1" is enough to dampen the rack shelf as well as the base platform. I used a combination of 1/2" particle board and glued to that a recycled paper board sold at HD as sheets that was designed to reduce noise and vibrations. My dad used it 60 years ago when he built a platform for my Lionel trains 1/2 in. x 48 in. x 96 in. Acoustic Insulation Sound Board-BSNAT85US - The Home Depot
Very interesting...that looks like it would be good for building acoustic absorbers/diffusers as well. I've actually got a whole box of the industrial rubber/eva pads mentioned a few pages back that I could try for an approximate 1" inch thickness. I'm just curious to try a thick piece of (cheap) foam to test out Just Walking's suggestion and try to get the compression reasonably close to 1" for a 4" thickness. The plan is (top to bottom): turntable chopping board layer of foam or eva pads chopping board roller blocks Those Symposium platforms look really nice!
Probably those eva pads have a durometer rating that is too high for the weight of your TT or any other piece of audio equipment except those beasts you read about in Stereophile and won't really help anything - just too hard. This is what I use and have success with 1" x 24" x 54" High Density Upholstery Foam
Likely so...I suppose in keeping with JW's math I technically just need something that compresses to 3/4 its standard thickness and the EVA pads are definitely too stiff for that.
What I'm rocking at the moment... Rollers on the bottom and springs in the middle. The springs are a (cough) "alternate" version of the Isoclear feet and I use one less spring in each foot in the front to balance the weight. This configuration produces a noticeable improvement in low bass extension and articulation over rollers or springs alone with a single layer. I might go out in search of some foam tomorrow but ultimately I'm going to try Isopucks in the middle layer.
Trasmitted energy (vibration, resonance, fine physical movement, etc.) has to be dissipated (usually as heat which is absorbed and dissipated by the coupled material). While you may not be able to feel the heat, it is nonetheless measurable with the correct, sensitive instrumentation. What happens when you couple two somewhat dissimilar materials (e.g., a hardwood furniture top or a butcher block to a bamboo butcher block) is not energy dissipation but rather a change in the resonance or vibration, etc., as it moves through the different materials. The fact that something is made of a bamboo, as opposed to maple or birch or oak or walnut, doesn’t make it useful in this application unless it is isolated with energy absorbing/dissipating feet.
I got myself Butcher Block Audio contraption, which is nice looking, made from maple, has isolation feet, 2 inch thick, nice logo and was less then $70 shipped. I figured an opposite - when I do not need it, I can then use it is great cutting board! They sell them on audiogon. I could not hear any difference, but conical feet on my table and motor now on much better for them wooden surface and no longer move from accidental touch, like it was on glass surface.
Correct. But making the point doesn’t help because all that happens when you couple somewhat dissimilar materials is that the energy transfer continues, only slightly abated and at a different range of frequencies because of the change in material. The marketing material written in support of bamboo products is all fine and dandy, but it’s so full of misinformation that it’s also difficult to know where to start when dismantling what the manufacturers of this stuff attempt to feed us. Bamboo’s principle virtue at the manufacturing level is that it is cheaply available in huge quantities and in a variety of form factors. That’s why bamboo has beome popular. The manufacturers of a huge variety of furniture and housewares products have been pounding away at the development and uses for bamboo for years and years and keep coming up with new products. Bamboo is a huge grass, it has some useful properties, it’s vastly plentiful, and it’s now even showing up in engineered flooring. Adding various sorts of adhesives during the manufacturing process is often stated as some sort of virtue when considering audiophile uses for bamboo products. Problem is, adhesives are merely a manufacturing reality without any side benefit for audio. When the adhesives cure, they become much like the materials they’re binding - that is to say, hard as rock. Without that adhesion and hardness a bamboo butcher block (for example) would be next to useless. But it’s purely imaginary that the existence of adhesives in any butcher block made of any sort of wood or grass somehow makes the resulting finished product enough of an energy absorber to make it beneficial to audiophiles. I’m not sure what point you’re trying to make here. Glass and water transmit energy quite readily. Separate two panes of glass with an inert gas gap though (i.e., in a standard double-glazed window) and you’ll have a reasonably good sound insulator. Everybody knows this. What you’re confusing with the glass and water and pencil thing is something called wave diffraction. It’s a optical wave effect with which we’re all familiar. The point is actually that the optics are changed but not abated. The pencil still looks identifiably like a pencil, just broken, and all of the light wave energy from generated and reflected photons still reach our eyes unabated. The energy is changed somewhat, but not reduced in strength and that’s why you can still see all of the pencil. As with coupling bamboo and some other shelf material, the energy transfer changes somewhat in resonance range but still causes resonance in the coupled material. Separate the two materials with an energy absorber/dissipator though (e.g., sorbothane feet, rubber of the correct composition, various dense foam materials, etc., etc.) and you end up with something like a double-glazed window. Then - Qapla’!
Yea, I had to play around with isolation between the bamboo block and the Lack table. I am trying to keep the block isolated and let it take care of the table. My ears are telling me I am doing pretty good right now. Took me two Rega tables and almost 2 years of fiddling to get there though.
It's interesting the way peoples experiences are different. I put a butchers block on vibrapods under my P3-24 and I've never looked back.
@Agitater Sorry, I was certified to teach Physics @ one time . . . the Broken Pencil (wave diffraction. It’s a optical wave effect with which we’re all familiar.) was meant to be a means to visualize a wave traveling through 2 different media. AFAIK, waves act as waves, whether they're on the ocean, in a glass of water, or your audio rack. It would appear as though your statement As with coupling bamboo and some other shelf material, the energy transfer changes somewhat in resonance range but still causes resonance in the coupled material. recognizes what's occurring only on the point of the waves' transmission from dissimilar materials, & not upon the dissimilarity within the bamboo itself. Bamboo is constructed in many methods, take a look @ this pic you can see that the bamboo "boards" have different ways of orienting the bamboo strands (vertically, horizontally) & that the temperatures reached in manufacturing can "discolor" the bamboo (Carbonized Strand Woven 3-ply Solid Bamboo Plank with Vertical Bamboo Core) IF we simply start out counting "layers" within the above example, I see (with one eye only) from top to bottom: surface/2 horizontals (one may just be edge color of surface layer), 2 vertical/horizontal/carpet. So in my mind's eye, the waves have travelled through at least 5 layers of dissimilar media just going thru the shelf. I'm not going to take the time to count the # of layers in the other direction, but again, there is an interface between each layer where I would believe the waves would, to quote you: As with coupling bamboo and some other shelf material, the energy transfer changes somewhat in resonance range but still causes resonance in the coupled material. BUT, you have failed to recognize this happening within the bamboo "board." AFAIK, the different adhesives likely result in variations in wave transmission. I'm really more concerned that someone NOT pick a product with added urea formaldehyde adhesives. I threw out "engineered flooring" early on, as what I observed was that the product was not 100% bamboo & neither was it encapsulated in a way to prevent adsorption of humidity (note remark on Menard's display warping). My impression is that this thread focuses on only one aspect of physics @ a time; rather than contemplate what may be occurring as the waves travel within the bamboo.
My ears tell me something good is happening in that cheap Ikea block. At least under a Rega. It might not do squat for a mass loaded table. Its cheap enough to try, and if you dont like what it does for the stereo, it makes a fine butcher block. Oh, and bamboo makes pretty good flyrods too. Much nicer than those tupperware things some folks use.
I’m sure it depends on your room, your floors and what the table was sitting on before the butchers block.
I'm sorry but you appear not to be giving any useful information and saying coupling two different materials doesn't dissipate more energy seems to defy the laws of physics. If you can give me some data on which your presumptions are made my daughter may be willing to check your calculations and hypothesis.
Waves continue in coupled materials. But, I never stated that waves continue unabated. I specifically stated that the frequency range would change. Amplitude may change too, but it is the degree of amplitude change that is of concern to audiophiles. Change occurs because, for example, a laminated maple cutting board has somewhat different resonant charateristics than a laminated bamboo cutting board. But they both resonate in some part of the audible frequency range, and their resonant characteristics overlap. It is the area of overlap that is of most concern. A 1” x 1” x 16” maple board resonates in a certain range of frequencies. A lamination of 1” x 1” x 16” maple sections resonates in a different but ovelapping range of frequencies. The strips are glued and cured under pressure, and therefore suitably hardened and finished for their intended use. The same thing applies to bamboo strips that are glued and cured under pressure to make a cutting board. When both types of cutting boards have come through the manufacturing process, neither one is better than the other at damping audio frequencies when placed directly on a resonating shelf or furniture top. They’re both relatively poor resonance dampers. Some damping does take place, but it is relatively small. That small effect can be beneficial in situations in which transmitted resonance from a shelf or furniture top is small to begin with. If you place one board directly on top of the other however, directly on a vibrating/resonant shelf or furniture top you are essentially coupling all of the surfaces as long as the surfaces are reasonably plane. There is no question that the range of frequencies and the amplitude of those frequencies will change as resonance/vibration moves through the two compositions, but the combination is rarely an effective damper and - at least for this sort of application - is a waste of otherwise perfectly good cutting boards. The amplitude of some frequencies may be reduced somewhat, without question, but it’s the relative activeness of the problem shelf or furniture top will determine the effectiveness of the chosen cutting board. As soon as you add energy absorbing feet to the ‘bottom’ of a cutting board of either type, or add a layer of energy absorbing stiff foam or sorbothane between two surfaces - essentially isolating the cutting boards from each other or isolating the cutting board from the resonant shelf or furniture top - and then place the assembly on a resonating shelf or furniture top, everything changes dramatically. Little or none of the resonance from the shelf or or furniture top gets through to the cutting board and whatever turntable is sitting on top of the cutting board. Only the resonance/vibration from the shelf or furniture top that is still being transmitted through the air will continue to have some tiny and probably inconsequential effect. None of this is presumption. It is based on practical application. There are some situations in which audiophiles have used genuinely massive cutting boards. That’s another story. When you get into 4” thick cutting boards with a surface area of 16” x 20” or more, they’re so massive that the typical sorts of shelf or furniture top vibration found in some homes has insufficient energy to excite resonance in the huge board. Some excitement takes place - always - but in such a situation it will usually be inconsequential. The massive board may be coupled to a resonant shelf or furniture top, but it is too massive and acts as a damper.
Yes and that agrees with my first statement not as effective but there is a beneficial effect and I don't know why you're saying isolating when putting a layer between the boards is actually coupling. And what do you mean by practical application in particular the relative merits of woods and Bamboo. I know there's data out there, as I was directed to it by a friend many years ago, if my memory serves me right Fiberglass and Bamboo showed similar results when compared to wood, due to their chaotic structure, which is significantly different than that of wood.
If you mate two generally similar surfaces directly to each other, e.g., dense, laminated cellulose compositions that have been glued and cured under pressure to form boards, you’re coupling the two boards. If you separate the boards with a layer of energy absorbing material that is radically different in density and structure, and that has the properties of energy absorption and conversion, then you’re isolating the two boards or surfaces from each other. The inherent physical properties of the material selected to act as an isolator are what determine resonance damping in this case. By “practical application” I mean the experimentation with a wide variety of plate and board materials and a wide variety of coupling and isolating and energy absorbing footer and materials, all for prospective use in isolating turntables from the surrounding environment and from the furniture or shelving or equipment racks on which they’ve been installed. I’m not sure what you’re recalling about fiberglass, nor do I understand where you get the idea that natural bamboo has a chaotic structure. It is the long, contiguous fibers in bamboo that give the grass its useful properties. For bamboo to be bamboo, and for a finished product to look like bamboo and be useful, bamboo’s inherent properties have to be retained. If, by contrast, some manufacturer simply shreds a stockpile of bamboo and then mixes it with adhesive and hardener and forms it, under pressure, into massive sheets that are then cut up for a variety of uses, it’s not really bamboo anymore so much as it is particle board or medium density (or low or high density) fiberboard. I don’t think that’s what you’re posting about though. Fiberglass, by comparison, is entirely synthetic. Fiberglass sheet is composed of layers of resin and hardener that are embedded into multiple layers of woven material, all formed on either a positive or negative mold of various sorts. That’s how fiberglass boat hulls, utility enclosures, panels and other things are made. The various ways of laying the woven material determine rigidity or flexibility and energy absorption (impact) characteristics, and so on. Fiberglass can be made into a highly resonant panel, or an acoustically dead panel, or into something in between. It’s a synthetic material that can be whatever you want it to be (within certain limits). Bamboo is a natural material. It’s a tubular grass that is relatively small in diameter compared to even the smallest hardwood tree that any respectable lumber company would harvest.Because of that difference - because you can’t cut a board out of a single bamboo stalk because the stalks are simply too small and the interior is very low density - bamboo has to be heavily worked in order to make strips that are then glued under high pressure in order to form boards of various dimensions and thicknesss (in laminations) that can then be used to create various products. But bamboo is still composed of long cellulose fiber. The other problem with working bamboo is that the grass hs regular nodes througout its structure. The larger the genera - there are 80 or 90, plus more than 900 species - the greater the distance between nodes. None of that makes the finished product a resonance damper.
Well it was a few years ago and my memory is not perfect but I'm now told, by my daughter, that Bamboo is significantly different than wood due to it's anisotropic structure, so forget chaotic. All this came from my friend who was doing computer modelling on construction materials over 15 years ago at Leeds Uni for his PhD, so apologies to him for my imperfect memory, it was Asbestos not Fiberglass.
Anisotropy is one of the physical properties of certain materials that have differences in tensile strength, absorbance, refaction index and some other things depending on the direction in which the force or effect is applied or the direction from which a measurment is taken. Wood of all kinds - softwood, hardwood, pine, maple, etc., etc., etc. - is absolutely and inherently anisotropic. The classic example of anisotropy is, in fact, a length of hardwood lumber. It is used in various sorts of instruction to demonstrate that it is notably easier to cut along the grain compared to cutting across the grain. I am not sure where you got the idea that bamboo is an anisotropic fiber and wood is not, but the notion is incorrect. Your earlier mention of the refracted view of a pencil in a glass of water is an example of anisotropy too. Depending on the angle of view, the pencil will either look broken or unbroken. The problem with most inexpensive cutting boards of any size is that they are not designed to damp vibration. Inexpensive cutting boards use long-grain lumber that are glued together under pressure, then planed and sanded to finished size. They vibrate relatively easily because of that construction, and so do similarly made bamboo cutting boards. Truly good cutting boards that last for years and years and years in a busy kitchen are made of end grain wood. That is to say, for example, 2 by 2 hardwood boards are chopped into, again for example, 2 inch long pieces. Then all those pieces, grain running vertically, are glued together under pressure and then planed and sanded to finished size. The difference in construction between the more expensive end grain cutting board and the conventionally inexpensive long-grain cutting boards is the key element. End grain cutting boards vibrate only fractionally compared to long grain boards. For another fact too, years of conventional use have to occur before end-grain cutting boards start showing deep cutting marks. The nature of the end grain construction tends to hide cutting marks in wood and bamboo boards. Long grain construction shows cutting marks quite readily and quickly. This is another example of anisotropy. Well thank goodness for that because there is no valid comparison between processed, fibrous asbestos (no matter what finished form it takes) and anything useful to audiophiles or anybody else who values his respiratory health. All wood is anisotropic. All bamboo in milled form is anisotropic. For use under turntables, please consider carefully what I posted above about long-grain vs. end-grain cutting boards. Further reduce energy transfer through a great, end-grain cutting board by attaching damping-isolating footers. If the footers also happen to be adjustable, that will also aid in levelling. Happy experimenting!
I've purchased three 1.5" thick, 4' X 8' strand woven bamboo workbench tops @ Sears (many locations of Sears Outlets had "damaged" tops, a scratch = significant discount). These have 2 horizontal/1 vertical/2 horizontal layers. Cut them into 2' X 2' "boards" weighing ~ 25 lbs, ~ $43 @. NOTE: 1.5" Thick Red Oak Edge Grain Countertop only 27" Wide X 8' = $765.00 + shipping. Plans call for these to be placed atop 3 or 4 (leveling will determine) E.V.A. Anti-Vibration Pads, 2" x 2" x 7/8", on 18" wide, upside down (to retain pads w/out attachment, & reduce distance between shelves), black ALERA Industrial Wire Shelving to form an AV rack 72" wide & < 30" high, below my Kuro 60" plasma. I hope to utilize casters to make wire maintenance accessible. In my mind's eye, the 1.5" shelves sitting out 3" over the black wire shelving should result in only the upright ~ 3/4" black posts being visible between them, with the shelves appearing to float.
I said that Bamboo is significantly different than wood due to it's anisotropic structure, as in being different. This comes from my daughter who has a some interest but her Masters is Mechatronic, she says I don't listen to the details. To be honest she really can't be bothered talking about it, she spent a year working for the M.O.D. some of her colleges were working on composites and she says it's interesting but fairly complex, however she tells me, she signed the Official Secrets Act (I suspect this may not be true). To sum her up "So many variables and it comes down to metaphysics, just listen, don't guess, get a life", she can be stroppy! And I think we're back to your room, support and HI-FI, so give it a try and don't forget placebo. And that's how I remembered it was asbestos as my friend did point out asbestos probably wouldn't sell as a Hi-Fi rack.
