user510, there are well designed turntables suspensions and not so well designed suspensions. Suspended turntables that have their sub chassis sitting on springs like the AR XA, LP 12 and Thorens turntables are inherently unstable and they tend to oscillate laterally when aggravated. They will skip with footfalls sometimes even more readily than unsuspended turntables. Suspended turntables that have their sub chassis hanging from the springs are inherently stable and want to maintain their resting positions. This category includes SME, some Basis and Sota turntables. They will not skip with footfalls. You can put them on a collapsible card table and they will operate fine without any audible consequence.
How to isolate turntable from footstep shake or vibration
Even while the Oracle turnable that I use has a built-in springs suspension by design there is a low or even sub-low frequency boom every time someone walks in a room. This becomes really bad with the subwoofer’s volume set high as the low frequency footsteps make straight to subwoofer where they are amplified shaking everything around. It seems the cartridge is picking up the footsteps very efficiently as even a lightest foot down becomes audioable. What can be done to attempt to isolate the turntable from the low frequency vibrations? Interesting, that the lower the volume of the subwoofer, the less the footstep shake is evident and with the subwoofer turned off it is a barely a problem at all.
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@williewonka , Sitting a turntable on opposing magnets is similar to sitting a turntable on springs and would be very unstable without some kind of lateral support. Hanging a turntable from attracting magnets would be an interesting project. My instinct says it would not perform any better than hanging a turntable from springs but would be a lot more expensive. |
@mijostyn - I was thinking more along the lines of actual magnetic feet - not a DIY solution - like these... Maglev HiFi isolation feet | Solid Air Audio And the link to the other Agon discussion has more examples of commercially available magnetic feet I think something like this would be too difficult to DIY Regards - Steve |
it sounds more like damping rather than isolation although it probably isolates at certain frequencies. If you want to have some fun put the stylus down on a stationary record and hook your phono stage to an oscilloscope. Then play a sine wave sweep loudly and see what gets through.@mijostyn Its both. I have tested it and the platform has proven remarkably wide band. I'd recommend the platform but the manufacturer went out a long time ago (Ultraresolution Technology). |
Hanging with magnets would not be a viable option unless the magnetic field strength was meticulously matched to the total mass of the turntable. Even the weight of the LP itself would have to be considered, and you’d have to take care not to rest objects on the plinth surface. Otherwise you would either have the equivalent of an unsuspended state (magnets in physical contact) or the sudden equivalent of nothing holding the turntable up as it crashed to the shelf or earth. Suspending the turntable footers between opposing magnets, top and bottom, might work. |
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