So I decided on purchasing a Townshend Seismic Platform. Then when it warms up here im going under my floor in the crawl space and going to add supports to the floor. Then I'll ask my buddy to mill the platform.
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andrei_nz Thanks for the info. Everyone on here has been very helpful. Do you know where maybe I cant find an exact schematic? I know that's asking for too much. He's the type that just needs the measurements and/or plans. Its puzzling to me how mini trampoline footers like the Isonoe can can be good for footfall.. I am intrigued though and might try them. Once it warms up here, from influence of these replays, Im going to get under my floor and add supports to the floor. BUT! If I can find a way out of it.. Ill try it (without breaking the bank). |
Given that you can have your own platter machined you should do the following: It should have a hollow space underneath. Think Technics SL1200 platter. It has a flat top (of course), and then at the edges it has a lip (with all those dots). Underneath is a rubber underlay. Do something similar but rather than a rubber underlay you will pour epoxy (g-flex is good). This will damp the platter. This is important if you are having a metal platter, otherwise it will ring like a bell. The constrained layer damping suggestions are also good. As regards footfall I have two suggestions. First add some mass. For example I use a one inch slab of granite on my shelf. Second get some aftermarket footers. There are maglev footers on ebay, Even better are Isonoe footers - they are in effect mini trampolines. I can jump up and down next to my TT without adverse effect. |
I have a Townshend seismic platform (it has pods attached under it) under my turntable. When installed, it improved the sound so much I was incredulous. Unfortunately, the very low waves from the pods combined with my suspended floor and extremely light turntable created footfalls that didn't exist before (to anywhere near that degree). It was either live with the improvement and tread lightly or go back to square 1. I was going to live with both because of the sublime sound. But, guess what - I put in a wall shelf ($179 from Project) and put the Townshend platform on top of that. All problems solved and the sound improvement had to be heard to be believed. I was very skeptical. I like the platform better than the individual pods because there is no fiddling around with placement. You can adjust the springiness in each spring to level the platform for items that have lumpy weight distribution. @millercarbon takes a lot of abuse from some posters, but I have to thank him for turning me on to Townshend. I had the privilege of talking to Max himself a couple times - extremely nice down to earth guy, very honest - kind of like a mad scientist who does his own research and has solutions that work. When he starts talking about continuous earthquakes, he is on to something. |
@bjw54 I have an old Sota on a walnut turntable platform that utilizes rubber balls. I’m a bit confused. What SOTA table do you have? And why do you have an internally suspended table (with springs, if that is what it is) on a separate base? That would seem to defeat the internal SOTA suspension system. My SOTA sits atop my rack, all by itself, and I can walk, jump, yell at, and bang on my SOTA Sapphire TT’s plinth, and it is not effected, by anything. Perhaps a bomb going on within the room might.....might. 😁 |
They are $1500 but an incredible upgrade for a TT-Silent Running Audio. VR platform. I put one under mine and the improvement in sound was the biggest change in my system short of upgrading my speakers from $10K ones to $30K ones! SRA has two separate companies that make vibration control devices for the military and medical. Submarines and CATs! It is clear, with over 40 patents, SRA devices allow complex machines and components to function as they were designed. |
As far as metal goes the one material that has been in use for machine tools for decades is a special grade of cast iron called Meehanite. It's known for it's superior damping quality's , very important when designing a machine tool. The last thing that a machine tool needs to do is vibrate or ring, it wouldn't work very well. I do believe it has been used before in a TT plinth, not sure who it was though. If your going to use aluminum, maybe check out cast tooling plate. Being cast instead of wrought it should offer better damping characteristics. It's offered in many thicknesses and comes in a machined finish on both sides. It's cut to size using large CNC circular saws. BillWojo |
I to live in a very old house with bouncy floors.In my secondary system I have an old Sota on a walnut turntable platform that utilizes rubber balls. When someone walks into this room the stylus skips. In my main system I have a VPI Classic 3 on a 4 inch thick maple butcher block platform with 4 rubber and cork anti vibration pads. I never have any skipping and can even rap on the rack without any issues. The vibration pads are the same ones that are used in the HVAC industry. These pads are very inexpensive and you will find that the same pads are being sold under some audiophile brand names priced at 10 times their actual cost! |
@antinn , said it pretty well. You will not isolated the turntable from anything with whatever material you choose. You could actually make things worse. Sometimes a wall shelf will help, sometimes not. You have to isolate the turntable from everything about three Hz. Including the dump truck that just drove down the road. You can feel it even on a concrete slab. The only sure fire way to do this is with a suspended turntable tune to less than 3 Hz preferably by hanging. SOTA and SME are the best at this. Sota's may look simple but they are very well made and very durable. You can also choose the wood if you like. For $10,000 you can have a perfectly suspended table with vacuum clamping, a magnetic thrust bearing, Top notch speed control and a dust cover to boot. Many of these feathers are available in less expensive table. There are many spring loaded devices on the market. I the dealer does not ask you for the weight of the table as it plays with recodes an clamps, forget it, move on. The springs have to be tuned to the weight of the turntable and you always go with the lightest spring that will work. 3 Hz. That is what you are looking for. Then you can kiss foot fall problems goodbye. |
@clearthinker Rolls Royce solution: Take up the floor, dig out a bit if required, lay new DPC, in-fill with concrete screed, lower floor level to get more ceiling height if desired. According to taste, re-lay boards except where equipment and speakers are to stand. Or lay carpet. As I have stated, you can get the same results for much less, simply by reinforcing the floor joists in the area of the table. In fact, I would never do what you suggest without doing so first, because you are adding more weight to a poor situation. Again, this is not unusual in wood framed floor houses, both old and new. Renovations and remodeling is my business, and sometimes need to do this to clients homes, and not for audio reasons. Let’s take an exaggeration; if your turntable is sitting on a trampoline, which you will also walk upon while using it, how much will you spend for a platform to remove the effect of the trampoline? That is allowing the ‘tail to wag the dog’. First, get rid of the trampoline, then see what you might need, if anything. I did this in my house before getting the SOTA. I had a few 2x4’s left over from a recent renovation project, used about 3-4 to support the floor beneath by rack. Took maybe an hour. I could then walk, jump, etc. next to my rack which minimized floor fall issues to a great degree. I think we can make simple solutions and over-complicate them, and make them cost more than necessary. |
I would use a run-of the-mill Technics turntable as a plinth... completely immune to footfall. What's the next problem? BTW, there are plenty of round things that are designed to vibrate and resonate...look at bells, cymbals and drums. Going square is probably fine. Just decouple it and add mass (that doesn't have a very uniform grain structure). How about good old concrete? |
+1 +1 +1 noromance You sure got it correct. Concrete is the answer to vibration and indeed marble and stone, and plenty of it. OP has a suspended floor above crawl space and bare earth below. Great start. Rolls Royce solution: Take up the floor, dig out a bit if required, lay new DPC, in-fill with concrete screed, lower floor level to get more ceiling height if desired. According to taste, re-lay boards except where equipment and speakers are to stand. Or lay carpet. OK there is a cost, but it will be worth it. Use marble or stone blockwork for equipment supports, standing on spikes (PLEASE NOT SPRINGS - BOINNGGGGG...GGG...GGG!). All you equipment will be rock steady, no vibration. It is mass-loaded to Planet Earth. Infinitely mass-loaded as I have said. OK, not quite infinite but the mass of the earth is quite large. This is absolutely excellent for turntables and speakers, good for CD players and amps benefit too. There is no ground-borne vibration (except in California) and the mass damps away all air-borne waves. I have implemented this construction in my sound engineered basement listening room. Improvement to SQ is much bigger than many component changes. |
Hello, I remember audiophile discuss we had during the vinyl " golden age" from middle of seventies to eighties" We had discovered the " sound" of the turntable highlighted by the audio litterature ( Ivor tieffenbrun Linn sondek) In general two approach have been acknoledged for the structure design The ratio of mass - plinth -platters-tonearm-cartrige tracktability( high or low) A) High mass plinth High mass platter High mass tonearm Low cartridge tracktability In this configuration the transmission of the energy of vibration is balanced B) Low mass plinth Low mass suspended (or not) platters Low mass tonearm Low tracktability cartrige In that case, the ratio of mass structure between the elements is also balanced So, what ever the platter structure is the " bell" effect must be be reduced keeping in mind that each component have specific " sound" never neutral.. I own two vintage turntables whitch are complying perfectly these rules as example - Thorens TD 124 II ( injected aluminium & cast iron) - sme 3012/2 & DL103) -Walker Cj 55 Wood and suspended platter in tufnol ( the most neutral backelit phenolic component to be used in aircraft for years) Colin walker was engineer who used to work for castle engineering in the seventies and launched the linn sondek and Ariston RD11s in uk, Usa and australia inthe seventies... Sorry fpr this backward looking story ! It is just my experience to be shared... Raymond |
To remove the Floor Bounce issue and Vibration Transmission to the TT. A TT Wall Shelf can be used. It will be at it most effective if a Wall is Bricks and Mortar Structure, if other structural materials are used, it will be best to seek out the ideal fastening to secure the TT Shelf. When Looking a a fastening for a Wall Shelf, Do Not ! just delect a fastening as you are familiar with it. Seek out the ones that has the best Kg Loading for the substrate to be fastened to. I found mine on Youtube and when fastened into Cinderblock, they are 250Kg per fastening. There is nothing like such reassurances. A DIY Sub Plinth can be made that can control various effects from Vibration. A low profile 'Side Wall' 1 1/4" (30mm) Tray can be made that is to contain a approx 5/8" (15mm) Depth of Kiln Dried Sand. This box can be sat on Sorbothane or Similar Footers. An additional Box will be made, that fits snuggly into the Kiln Dried Sand Tray, a 1/8" (3mm) clearance all round between each boxes 'Side Walls' should be ample space. A base can be cut for this Box, that is 1/4" (6mm) smaller that the inside dimension of the Trays 'Side Wall'. The following is a Crude Version of a early Townshend Design. It works on par with any type of design using the concept. This Box will be a Housing for a Inflatable Inner Tube, a Side Wall will have a Vertical Slot cut in, to allow the Valve to exit the internal space. The Slot allows the Valve to elevate freely when inflating. The Height of the Side Wall will need to be determined by how much inflation is chosen for the Inner Tube. When the ideal inflation is discovered the Inner Tube can be placed on the Kiln Dried Sand, a Dimension can be taken from the base of the of the box that will be approx 10mm above the Kiln Dried Sand (The inner Tube should be close to 10mm above the Side Wall when inflated, do not make a excessive dimension, as the 10mm will allow the assembly to find a resting place in a controlled manner if a inflation is decreased over time ). Place the Box with inflated Inner Tube onto the Sand, with the Inner Tube seated on the Sand. Place the TT on the Box/Sub Plinth and check the TT for Level. Footers under the Plinth will assist with achieving the levelling that is required, as well as offer a further Vibration Control. Footers are also going to attenuate the sound, so finding a ideal one is a personal experience and down to ones preference. My Footer of choice in direct contact with a TT Plinth is Solid Tech 'Feet of Silence', these were put into Service after using AT-616. As said the choice becomes personal. Note: The Box with the Inner Tube can be seated in reverse with the Boxes Sub Plinth being seated on to the Sand. This will allow for 'different material Sub Plinths' to be seated onto the Inner Tube, this is another way to fine tune attenuation to suit a personal preference. This assembly can be achieved at a reasonable cost and a allocation of ones time, it will offer a vast improvement over a conventional Support/Rack that is in direct contact with floor. The cosmetics for the finishing will be a little more to be added to the parts used, if the raw honesty is not desirable. Apologies for the Long Mails, I'm living in a Lock Down, so Coffees and Keyboard are part of the Day Filler. |
Antinn gave you good advice. Constrained layer damping is an important element in most plinth designs - it’s often absent and that’s always obvious. If you want an easy solution, I use Delignit panzerholz B25, which costs about $1000 a sheet. In my plinth, constrained layer is partly in the plies of beech wood in the panzerholz, and partly from a top layer of carbon composite. Rigidifying your floor is even more important. My floor is concrete - it’s great - and as others have suggested, try to make your floor as much like concrete as possible. Good luck! |
@deanshias, As others have said , Townsend knows what he talks about. But, let me if I can expound upon what he said. If you view Figure 7 of this Fundamentals of Vibration (newport.com) , when your designing a vibration isolator, the resonant frequency needs to be less than the Hz you are trying to isolate. At resonance (and all vibration isolators have one), any vibration is amplified and this is called the transmissibility. The damping factor reduces the transmissibility peak, but reduces how quickly (the slope) the vibration is reduced after the resonant frequency. So when Townsend say a damping factor of 0.16 - that is near optimum. Townsend may very well have a curve that looks like Figure 7; and each design is limited to a range of supported weights. Because of the low frequency (foot fall) you are trying to isolate, which has a lot energy associated with it you have an engineering problem that the number of solutions is pretty limited. You can dismiss as you wish; and spend all the $$$ you wish; but your up against some very hard truths. Good Luck. |
Butcher block acoustics makes affordable and good looking isolation platform made of wood, maple or walnut. Been using them for years to good effect. Can be bought with or without metal threaded inserts for the feet of your choice, which they also sell. My latest in maple replaces an existing wood shelf that came with my turntable wall mount, so no inserts and no feet required, as the isolation rubber feet are integrated into the turntable wall mount. The wood is very hard and so I can do without the tip toe discs on the turntable. Wood is a far more "dead" material than metal. Not sure why one would consider metal. Between the added butcher block, the dual plinth design of the turntable, the TT tip toe feet, and the fact the shelf is bolted to a concrete outside wall which faces the back of house, and away from "possible" street/traffic induced vibrations etc....not sure I can better my set up much. Plus the shelf is up high, eye level when standing....well above speakers. I tend not to worry about so called seismic vibrations, unless there is a 6 on the richter scale. 😁 |
if you can brace the floor, your solution at the table will be greatly minimized.+1 @bkeske Good to see you taking the advice. Install a concrete plinth directly beneath the turntable for maximum stability. I ended up in the concrete basement such was the improvement in sound quality over suspended floors, live walls, and all manner of vibrations. |
The theory of more stuff. Vibration isolation in audio is a subject surrounded in mystery half truths and any number of wild theories. As an engineering exercise, the explanation is quite straight foreword and may be explained by the “Theory of more stuff”. Take a surface, be it the floor or a table, on which your hi fi component is placed and it is desired to reduce the vibration from the support to the equipment. The way this is done is to put “some stuff” between the equipment and the supporting surface. There are three possible outcomes. 1 The vibration in the equipment is more than the vibration in the support. 2 The vibration in the supported equipment will be the same as in the case of no stuff. The chances of this are one in a million because something has been changed… it may be the same, but that is extremely unlikely, therefore, the only possibility is, 3 The vibration will be attenuated, to a greater or lesser degree, and this is the case. There are many products out there that do in fact attenuate vibration. Be it spikes on glass, wood and slate, aluminium spikes in cups, ball bearings in cups, solid plates separated by compliant sheets, lead, Bluetack, sand, marble, concrete, the list is endless. It is also known that multiple combinations of the above produce better results because there is more stuff. E.g. multiple platforms stacked really high. The engineering approach is to get the best result in the simplest manner by optimizing the “stuff” and way back about two centuries ago the Victorian engineers came up with the solution…. the spring! The spring may be anything “springy”, from elastic, rubber, coiled steel, straight steel, air-bladders to flexible wooden strips. As long as it has sufficient spring or compliance, when optimised with an appropriate mass, a mechanical low pass filter is realised. The ideal is to have the resonant frequency as low as is possible, ideally around 2Hz in both the horizontal and vertical planes and with a damping ratio of about 0.16. This will give an attenuation of about 25dB at 10 Hz increasing at 20dB per decade above. This will ensure excellent isolation for the deleterious audio system vibrations which are from 5Hz to 500Hz.
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Don’t go crazy, but dekay has a reasonable idea. When actually leveling a floor, you have to know what your are doing, and do it fractions at a time, for a variety of reasons. All you want to do is reinforce, stabilize, and provide support at the joists along the area where your turntable is. Thus, if you use a jack, I would not raise the area more than a 1/4”, put a couple 2x4’s, or perhaps get some treated 4x4’s, stand them in place (on a 12x12 concrete block as a ‘footer’) and lower the joists back down upon the vertical 4x4 with the jack. Pretty easy actually, but depending how much crawl height you have, can be cramped, so scope everything out, precut the lumber, etc. There is no real need to make full height pilasters out of block for what you are doing and trying to achieve, that would be overkill. |
A well isolated turntable will not be bothered by anything. This requires a suspension. If you really want to isolate an unsuspended turntable you get a MinusK platform. They are the best. But , if you get a properly suspended turntable you can put it on a foldable card table and it will not care. Examples are the SME turntables, Sota turntables, The Avid Actus, The Kuzma Ref 2, Basis turntables, Dohmann turntables, Oracle turntables and probably a few I do not know about. You can put almost any turntable on a MinusK platform and get excellent isolation. |
Ok.. yes.. as much as i said i can never handle my crawl space and would never go under there.. if its for the love of getting rid of vibration for the ultimate analog bliss.. im gonna do it! Im gonna lift this freaking house up. Do i move out as much furniture, etc., out of the room before lifting it? |
"There's crawl space under my floor." Then... When weather permits crawl in and use basic/inexpenisve items to support the floor under your TT. You would need to lift the joists (scissor jack form your car?) maybe half an inch, or so, and then block/support them with cinder blocks/and perhaps suitable non-compliant shims allowing gravity do it's job once the joists are lowered. Hate crawl spaces myself, but once done (depending on the lower/ground surface) the remedy should last years, if not decades. I used to place my TT's in closets (including unused Murphy bed closets) in old rental units due to to the added bracing/structure those specific areas afforded. Curent TT is also in a closet (along with all the electronics), but for other reasons. I now use specialty shelving, upturned brass spikes, et cetera, however my floor is quite stable (aside from the occasional earthquake and/or Air Force afterburner flyovers/drills). A stable floor is the main goal, if it can be accomplished within reason/budget. DeKay |
I'll add my two cents: the kind of metal that isn;t metal. Do a constrained-layer dampening plinth, and suspend it on whatever you want. Look it up - surprisingly easy and surprisingly effective. You want something that will not resonate within the audio band (or anywhere it is likely to beat into the audio band) |
Well.. yes.. the original question was for the platform.. but since someone else brought up footfalls.. which was always a bigger problem.. why not ask to get as much help on it. Ive asked about it in the past but the info you guys are giving is better than anything ive hearf in the past. Again.. i do have a friend with a CNC machine that can make almost any type of metal platform.. so yes.. any info does help with that. |
You don't need CNC, unless you yourself make it a requirement. What you need to eliminate footfall problems is a two stage approach. First stage, mass eliminates large amplitude low frequency footfall type vibrations. Second stage, springs isolate the turntable from the smaller amplitude higher frequencies that get past the mass. With a superior product like Townshend Pods your table will probably be fine even with your existing rack. People who have PM'd me about problems like this tried Pods and they work great in situations much like yours. They work even better in situations like mine, which is why it is still a good idea for you to build a sturdy low profile rack with a massive sand bed. As described above. You really should as a general principle ask the question you want answered. You came here asking about metal when really it is about footfall problems with your turntable. At least that is what it seems to be. Until it changes yet again....? |
Look... I'm not knocking the SOTA (except for its looks :). If I dont solve this, then I might consider it. I just didnt want to be limited to ONE turntable in this room. I was considering a VPI Prime Signature in a year or two as the next TT. But with this room the way it is, I dont see that happening. the concrete blocks/wood as a footer does sound like the logical thing to do... So there's noooo other way to deal with a footfall im assuming? Is this why im getting woofer flutter/pumping with almost anything I do? |
There’s crawl space under my floor. SOTA has came up many times for my situation, but I do really like this TT and want to make it work. Even if I wall mount I feel that the flexible floor vibration will creep into the wall. Well, you could still do it, just not as easy. Dirt or gravel floor in the crawl? Or concrete? If dirt or gravel, you could get 12x12 concrete block as a simple ‘footer’ sitting on top the dirt or gravel, and then brace the 2x’s off of that. Your problem is the floor joists were undersized for their span, or at the limit of acceptable design, which equals ‘bounce’. Not unusual in an older home. Fine for most folks, but not for most turntables, except the SOTA, of course. 😁 if you can brace the floor, your solution at the table will be greatly minimized. |
