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Dumped the rack
So I have a steel spiked Sound Organization table about 2 feet tall. On it rests a 3" maple butcher block. On that rests my slate Garrard 401 with slate feet and aluminum cones.
I had a piece of granite made and installed it on the maple beneath the turntable. Man, that sounded bad. Silvery colored and dull. I reversed the layer order and put the granite below the maple. That sounded a lot better. But not as good as when there was no granite. So I took it back out. Okay back to how it was. But something was missing. The granite did bring a feeling of stability to the image. What to do? I took the whole rack thing out of the equation and put the 401 on the concrete floor along with the preamp. This sounded best notwithstanding the wooden tone lost by removal of the maple. But the best thing, and I’m aware of the effect from reading but never tried it, was that imaging has improved by quite a margin. Like removing a veil of something. Like when someone moves their head out of your face at a concert. Now, I have to bend down to play records.
I had a piece of granite made and installed it on the maple beneath the turntable. Man, that sounded bad. Silvery colored and dull. I reversed the layer order and put the granite below the maple. That sounded a lot better. But not as good as when there was no granite. So I took it back out. Okay back to how it was. But something was missing. The granite did bring a feeling of stability to the image. What to do? I took the whole rack thing out of the equation and put the 401 on the concrete floor along with the preamp. This sounded best notwithstanding the wooden tone lost by removal of the maple. But the best thing, and I’m aware of the effect from reading but never tried it, was that imaging has improved by quite a margin. Like removing a veil of something. Like when someone moves their head out of your face at a concert. Now, I have to bend down to play records.
Showing 10 responses by geoffkait
jkuc This is why Townshend audio applies rubber. Actually it’s the air inside the rubber with a vent that damps the spring. https://www.youtube.com/watch?v=OZxi1oZfvDA geoff, I didn’t know you are using a hammer on your super springs when music is playing :). I like this one also: Plus the springs under load are constrained from ringing, like using your fingers to stop a tuning fork from ringing.It’s a good one. >>>>>The rubber “bellows” in Townshend’s design overdamps the system. The rubber restricts the vertical and rotational motion, which doesn’t help isolation, it hurts it. The motion was much better (less resistance) in the beginning of his demonstration with springs only. Isolation is defined as ease of motion in a particular direction. The motion is obviously easier and less constrained with springs only. One advantage to the rubber bellows is it provides some additional lateral support for the iso system so that speakers with a high center of gravity won’t flop over. Having the framework to spread the springs out in a wide pattern is also to increase lateral support. I can do the same thing only better with four springs and a maple board. 🤗 |
Actually, damping or constraining springs in any manner is a bad idea. People have suggested everything from silk fabric to an oil bath to rubber. The best sound is without any damping. If you’re worried that springs ring when you strike them with a small hammer don’t strike them with a hammer when music is playing. 😬 Plus the springs under load are constrained from ringing, like using your fingers to stop a tuning fork from ringing. Any issues your component might have with high frequency vibration will be affected by mechanical acoustic waves as well as transformers, CD transport mechanism noise, etc. That’s why I oft say a complete plan of isolation and resonance control is required. But the primary problem is the very low frequencies, not the high frequencies, the ones lower than the lowest frequencies the speakers can produce. Any residual vibration on the top plate of the isolating device can be dealt with easily by careful application of damping. Finally, the spring itself does not isolate vibration, it’s the combination of mass and spring that forms the mechanical low pass filter of the isolator. |
But in that case the system would behave non-uniformly due to unequal loads on the springs. Ideally, when you push the top plate up and down you want to see smooth vertical up and down motion. With unequal loading on the springs the motion up and down cannot be smooth, it will be wobbly, diminishing isolation effectiveness. |
My Super Stiff Springs will isolate 60 lb. nicely. Just place one spring under each corner of the slate turntable directly on the concrete slab, no carpet. Easy as pie. 🥧 And they’re only twelve bucks each. As it turns out the 3” concrete slab moves too, just not as much as wooden floors, and at frequencies that interfere with the tonearm, platter and cartridge resonant frequencies. |
You did the right thing. Racks are bad Gnus. 🐂 🐂 🐂 By and large racks exaggerate (amplify) the effect of vibration, that’s why modern buildings are constructed to prevent minor earthquakes from being amplified by the building structure. The one-mile circumference HQ building of Apple in California is built on huge slip plates for earthquake protection. One inch granite might ring. Three inch granite doesn’t. It goes thunk! Besides, what you really want to do is isolate the TT, and use thick granite for the top plate. Then the granite will be isolated, too. The granite top plate provides excellent isolation against rotational (bending forces). And use a mass-on-spring iso stand. Guess what provides the mass. |