Well I've gone back to listening to a lot more vinyl lately and I've come to the realization that I have to do something to better isolate the turntable (an older Rega Planar2 w/a modded RB250). Currently it sits on top of a media cabinet and a decent footfall on the hardwood floors will cause a jump.
Mounting a shelf on the wall is not an option (fails SAF).
I have a big slab of granite (freeby from a sink cut out) that I was planning on making into a sub-plinth. It will probably weigh 20+ lbs once I trim it to size. I am looking for any ideas on the best way to put things together in terms of feet for the slab, etc. Cheap is good.
Eventually I will probably re-plinth the Planar2 entirely to get better motor isolation, etc. But right now I'm just looking for something quick-n-dirty that will get the job done and not look too bad.
Any ideas?
Thanks,
-bill
Mounting a shelf on the wall is not an option (fails SAF).
I have a big slab of granite (freeby from a sink cut out) that I was planning on making into a sub-plinth. It will probably weigh 20+ lbs once I trim it to size. I am looking for any ideas on the best way to put things together in terms of feet for the slab, etc. Cheap is good.
Eventually I will probably re-plinth the Planar2 entirely to get better motor isolation, etc. But right now I'm just looking for something quick-n-dirty that will get the job done and not look too bad.
Any ideas?
Thanks,
-bill
Don't do it. For some reason stones seem very appealing as "isolation" platforms, yet they provide the opposite of isolation. Marble and granite have a distinct, strong acoustic flavour which i find seriously amusical. Slate, thanks to high internal damping is much, much better, but suffers WAF in comparison.
A composite structure (Simposium platform clone), or a platform on top of an inner tube is a much better solution.
If there is any way to float 2 pcs back to back, you could make an air float platform that would be superior to those rigid turntable ideas that transmit every vibration known to man into the table.
Granite is a perfectly stable material for surface plates that keep a constant flatness at all times in all kinds of temps
I would not make a plinth out of granite though, too high a Q and not flexible enough for this
Regards
David
Granite is a perfectly stable material for surface plates that keep a constant flatness at all times in all kinds of temps
I would not make a plinth out of granite though, too high a Q and not flexible enough for this
Regards
David
Stone works - sort of
I have used stone slabs for years and when I remove them, my system looses something.
However...
When I used a plain slab of stone under my 'table, it would sometimes seem to be adding something unpleasant. Then, I was reading some stuff about constrained layers and resonance and got the idea that the nasties were coming from resonance in the stone slab (yeah, a sink cut-out).
What I did was got a piece of 3/16" plywood, cut it to the size of the stone (slightly smaller, actually) and 'glued" it to the bottom of the stone with a whole tube of silicone seal. I did my best to spread the silicone over the whole surface about 1/8" thick. I let it cure (2 days) and then put it back in place under my 'table'. Results: wow! The sound from my 'table gained solidity and definition, with much better clarity and highs that I had no idea my cartridge could produce.
This is a very simple and affordable fix and works as well as many high-end platforms.
I have used stone slabs for years and when I remove them, my system looses something.
However...
When I used a plain slab of stone under my 'table, it would sometimes seem to be adding something unpleasant. Then, I was reading some stuff about constrained layers and resonance and got the idea that the nasties were coming from resonance in the stone slab (yeah, a sink cut-out).
What I did was got a piece of 3/16" plywood, cut it to the size of the stone (slightly smaller, actually) and 'glued" it to the bottom of the stone with a whole tube of silicone seal. I did my best to spread the silicone over the whole surface about 1/8" thick. I let it cure (2 days) and then put it back in place under my 'table'. Results: wow! The sound from my 'table gained solidity and definition, with much better clarity and highs that I had no idea my cartridge could produce.
This is a very simple and affordable fix and works as well as many high-end platforms.
Here are some links to some DIY isolation platforms that I home you find helpful.. 
Custom DIY Isolation Platform Table : aka sandbox
The TNT SandBlaster 1.0
http://thecarversite.com/yetanotherforum/default.aspx?g=posts&t=3228
Garbz's Haus
Custom DIY Isolation Platform Table : aka sandbox
The TNT SandBlaster 1.0
http://thecarversite.com/yetanotherforum/default.aspx?g=posts&t=3228
Garbz's Haus
stone can work...
... at least my 3" X 18" X 20" pieces of tombstone (pink granite) do... ain't nothin' gonna move that around (whimpy small vibes....).
But there are other solutions than a brute force one. I've used bicycle inner tubes (worked the best under my cd player) as an "air support".
It all depends on what you are trying to accomplish. There are two thoughts. If trying to minimize vibrations in a source component then stone (or other high mass stuff, like concrete) is not appropriate. Dampening is required. If vibes try to pass from one medium to another (such as from a turntable to a denser material such as marble or granite), most will be reflected back. This is what I suspect happened with Jesse's first experience. Once he provided a constrained layer (the wood layer and the silicon goo), it helped to dissipate the small vibes to it's surrounding.
Mass can help isolate a component from external vibrations (like a 40 ton highway tractor and trailer speeding down your street).
... at least my 3" X 18" X 20" pieces of tombstone (pink granite) do... ain't nothin' gonna move that around (whimpy small vibes....).
But there are other solutions than a brute force one. I've used bicycle inner tubes (worked the best under my cd player) as an "air support".
It all depends on what you are trying to accomplish. There are two thoughts. If trying to minimize vibrations in a source component then stone (or other high mass stuff, like concrete) is not appropriate. Dampening is required. If vibes try to pass from one medium to another (such as from a turntable to a denser material such as marble or granite), most will be reflected back. This is what I suspect happened with Jesse's first experience. Once he provided a constrained layer (the wood layer and the silicon goo), it helped to dissipate the small vibes to it's surrounding.
Mass can help isolate a component from external vibrations (like a 40 ton highway tractor and trailer speeding down your street).
I tried sandboxes under my valve amps, spiked to the floor. Then I went to a homemade rack system, with shelves suspended on polypropylene "wires", strung corner to corner of the rack, and that seems to sound cleaner. I have various shelves, granite, MDF, foamed vinyl, slate, but to be honest my system is not "clean" enough to tell the difference between shelves. At the moment.
As for constrained layer damping, my (admittedly limited,) understanding is that the layers need to be tightly bonded together to constrain the microscopic movements in the materials involved. Glueing with silicone adhesive is probably too soft to qualify, but that is not to say it won't work, probably just a different mechanism involved. Hopefully someone with engineering knowledge will set me (and you?) right on this.
With the inner tubes, I found cheap soft ones give a more compliant support than good strong ones. YMMV, of course. Under a preamp they were a bit stiff, but under my speakers I get about 2Hz resonance, like Seismic Sinks.
With an earlier version of my speakers, hanging the mid/treble cabinet from a frame with shoe laces (cotton? Does that matter??) above the bass cabinet, instead of spiking them together, cleaned up the BASS amazingly; active xover at 180Hz, so the mids carried a lot of bass as well.
There are a lot of different ways to isolate or damp, and I am lucky enough to be able to make and try different things. Now, if I could just remember which one was which........
Sounds like a crash barrier might be needed there!
With enough mass - say some large boulders in the metric ton range - you might be able to isolate the house form the road vibrations too!!!
I once lived in a shaky old house built in the late 1800's and getting things stable there was a challenge - wound up using a reel to reel to play most music to avoid the TT.
Squash balls work well . Loricraft use them on the Garrard 501 and openly admit it . 5 are used . Worth a try . I have used big bubble wrap .
Best I came across was brass cones with maple wood support . The guy was most insistent it was the best . I never told him I liked it as he went on so much about it . Brass not bronze he said . They were big cones . No idea if it works in another situation . I imagine marble under that would be great .
Best I came across was brass cones with maple wood support . The guy was most insistent it was the best . I never told him I liked it as he went on so much about it . Brass not bronze he said . They were big cones . No idea if it works in another situation . I imagine marble under that would be great .
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Jesse, pls PM me. More comments on isolation: internal vs. external
For most of us the intrusions of relatively high energy low frequency vibrations is what upsets the sound. I currently have this problem. I live in a rented house, that has very poor floors (as in springy). If I walk past my turntable while playing I can easily upset it. With the addition of the slab of granite underneath my equipment stand, the effect essentially disappears. Then the stand can do as it is suppose to do, isolate each component from one another. This does nothing to effect the actual resonance of each individual component. The only way to deal with that is to ensure that each component has enough internal dampening, or has the means to absorb and radiate any vibrations away.
One way to create an increase in internal dampening is to use a dampening material such as "Dynamat" or similar. Basically adding an elasto-polymer or rubber of some sort. Another option is to remake the component cabinets out of one of nature's best inventions: wood. It seems alot of these issues were just not considered or did not interfere with the enjoyment of music when most everything in audio was made of wood. It seems to me that as manufacturing went away from wood cabinets for audio components, the issue of internal vibrations and the smearing of sound occurred. I suspect if we made new wood cabinets for our gear, many of the internal vibrations would be "naturally" disapated.
Isolating a component from its bretheren in an audio rack or stand requires decoupling of components from each other. The use of Isolation platforms or shelves are indicated in this instance. The best isolator ? No isolator. But obviously that it is not practical. So a couple of things come to mind. Air bladders (inner tubes) and sand boxes can be used here (sandboxes can be considered as isolating from external vibration and isolating or controlling internal vibrations. and for this reason they work well in a great number of systems).
Another option is the "hung" or "strung" or "suspended" types of racking or shelves. These do require a little more of thinking prior to implementation if DIYing yourself. Hardware can get a little expensive if using these sorts of materials. Unlikely to be cost prohibitive as a commercial stand, but not cheap either.
Personally I have found combinations to work well. I have never used any sandboxes. Placing my equipment rack on my slab of granite seems to isolate the it from external rumbles. The use of inner tubes and such works well under most components as long as the tube can handle the mass (something to consider if using underneath any component approaching 50 lbs).
Regarding the suspended type, my audio partner is returning here for a month and we have a few audio projects on the go. One is an ultra light, ultra rigid rack with the potential for suspension of the shelving for isolation. Once completed I'll post some pictures and some comments regarding the sound of it. This is based on the "80 20 rack" over at Audiokarma (I think). But the suspension portion will be our take on it. I suspect I will do a write up of it for Affordable$$Audio.
One last comment: Squash balls. Me and my audio partner retrofitted a Roksan Xerxes (MkI) with squash balls used as springs intead of the "blobs" or whatever the Roksan folks call the threaded rubber/steel suspemsion pieces. They worked well therre, as the subchassis is relarively light. Trying to use squash balls under my old Alex didn't really work. The table literally "squashed" the balls.
For most of us the intrusions of relatively high energy low frequency vibrations is what upsets the sound. I currently have this problem. I live in a rented house, that has very poor floors (as in springy). If I walk past my turntable while playing I can easily upset it. With the addition of the slab of granite underneath my equipment stand, the effect essentially disappears. Then the stand can do as it is suppose to do, isolate each component from one another. This does nothing to effect the actual resonance of each individual component. The only way to deal with that is to ensure that each component has enough internal dampening, or has the means to absorb and radiate any vibrations away.
One way to create an increase in internal dampening is to use a dampening material such as "Dynamat" or similar. Basically adding an elasto-polymer or rubber of some sort. Another option is to remake the component cabinets out of one of nature's best inventions: wood. It seems alot of these issues were just not considered or did not interfere with the enjoyment of music when most everything in audio was made of wood. It seems to me that as manufacturing went away from wood cabinets for audio components, the issue of internal vibrations and the smearing of sound occurred. I suspect if we made new wood cabinets for our gear, many of the internal vibrations would be "naturally" disapated.
Isolating a component from its bretheren in an audio rack or stand requires decoupling of components from each other. The use of Isolation platforms or shelves are indicated in this instance. The best isolator ? No isolator. But obviously that it is not practical. So a couple of things come to mind. Air bladders (inner tubes) and sand boxes can be used here (sandboxes can be considered as isolating from external vibration and isolating or controlling internal vibrations. and for this reason they work well in a great number of systems).
Another option is the "hung" or "strung" or "suspended" types of racking or shelves. These do require a little more of thinking prior to implementation if DIYing yourself. Hardware can get a little expensive if using these sorts of materials. Unlikely to be cost prohibitive as a commercial stand, but not cheap either.
Personally I have found combinations to work well. I have never used any sandboxes. Placing my equipment rack on my slab of granite seems to isolate the it from external rumbles. The use of inner tubes and such works well under most components as long as the tube can handle the mass (something to consider if using underneath any component approaching 50 lbs).
Regarding the suspended type, my audio partner is returning here for a month and we have a few audio projects on the go. One is an ultra light, ultra rigid rack with the potential for suspension of the shelving for isolation. Once completed I'll post some pictures and some comments regarding the sound of it. This is based on the "80 20 rack" over at Audiokarma (I think). But the suspension portion will be our take on it. I suspect I will do a write up of it for Affordable$$Audio.
One last comment: Squash balls. Me and my audio partner retrofitted a Roksan Xerxes (MkI) with squash balls used as springs intead of the "blobs" or whatever the Roksan folks call the threaded rubber/steel suspemsion pieces. They worked well therre, as the subchassis is relarively light. Trying to use squash balls under my old Alex didn't really work. The table literally "squashed" the balls.
I met a professor Dolly of Harwell in Oxfordshire about 30 years ago . He was asking about this subject and got furious with me when I suggested what we are talking about here ( he stated the BBC used about 50 kg ) . I think the late boss of SME said 50 tons is about right for a turntable support .
The prof was indignant and started saying how could I be so certain . My answer was he should get an oscilloscope and measure it . 60 dB dynamic range was set ( about what a record can offer ) . Soon I get an excited phone call . I am wrong and the problem is ten times my estimate ( 500 tons ) . The stylus was placed on a stationary record . He could see his wife's footsteps going down the garden as she pegged out the washing ( he said ) . Ironically he was near the Didcot power station . Nothing from that ( I asked ) !
Remember an Ortofon pick up might need a gain of 20 000 at 20 Hz ( 100 uV type SPU ) . That will make the problem worse . Add a gain of 25 from the power amp at moderate volumes to get half a million .
On the strength of this the prof bought a B&O turntable . I didn't get that !
Some people make magnetic levitation tables . Looks easy to do and might work ( lots of small magnets ) . Will need stabilizing if so ( rubber bands ) .
The prof was indignant and started saying how could I be so certain . My answer was he should get an oscilloscope and measure it . 60 dB dynamic range was set ( about what a record can offer ) . Soon I get an excited phone call . I am wrong and the problem is ten times my estimate ( 500 tons ) . The stylus was placed on a stationary record . He could see his wife's footsteps going down the garden as she pegged out the washing ( he said ) . Ironically he was near the Didcot power station . Nothing from that ( I asked ) !
Remember an Ortofon pick up might need a gain of 20 000 at 20 Hz ( 100 uV type SPU ) . That will make the problem worse . Add a gain of 25 from the power amp at moderate volumes to get half a million .
On the strength of this the prof bought a B&O turntable . I didn't get that !
Some people make magnetic levitation tables . Looks easy to do and might work ( lots of small magnets ) . Will need stabilizing if so ( rubber bands ) .
Me too, I use squashballs with my 401 plinth.
That said proper isolation on a wall mounted shelf makes the real difference.
Rega's are much better with rigid mounting.
Soft bouncing suspension systems within turntable plinths (LP12, systemdeck, Pink Triangle) are actually designed to simply isolate internal vibrations from the motor, stop these getting to the arm. Suspended decks are actually far worse for external ones. If you have only used a turntable in a room with a concrete floor you won't have experienced this difference between suspended and non suspended.
With any of these suspended decks on a surface attached to the floor you have to be careful how you walk past the deck (I have experienced this with all of the decks I mention above, not tried Xerxes in that room).
With the Rega or the Garrard 401 attached to a shelf mounted on a brick wall I could happily jump up and down (probably go through the floor!) and not even the slightest hint of a wobble on the deck. I appreciate not everyone has this option.
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