That is disappointing. It means that vibration is getting to the sub chassis in spite of the suspension either through a poorly designed suspension or directly vibrating the sub chassis. You can try damping the suspension by stuffing some foam in the springs. Later versions of the Oracle add adjustable damping. Subwoofers are a huge problem for turntables especially if you have them set where they should be. The low frequencies will fibrate the tonearm directly through the air. It is very important to use a subsonic filter and digital filtering is the only way you can do this effectively without injuring the bass. I roll off at 18 Hz 80 dB/oct. I use a Sota and a large subwoofer array and have absolutely no issues. The turntable is however on a very heavy cabinet on a concrete sub floor. I have used the Sota on several wood floors over the years without any difficulty and have seen SME's and Basis tables do the same. Adding mass under the table usually does not help. The floor just bounces at a different frequency. There is a chance that the problem is not vertical vibration but lateral vibration in which case using a sturdier rack and damping the springs will help. You still should look into a subsonic filter.
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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I do not use a suspended turntable but I have had successful isolation using an HRS platform (S level) and a Vibraplane. They both work well independently and even better together. Obviously, I would try some simple footers first as you could end up spending more on isolation than on the turntable itself. |
mijostyn ... It means that vibration is getting to the sub chassis in spite of the suspension either through a poorly designed suspension or directly vibrating the sub chassis ...Not necessarily. If this is an Oracle Delphi (the OP doesn't say what model Oracle he has), then setup is even more critical than with many turntables. Its springs need to be individually rotated within the suspension towers so that the entire suspension functions pistonically. It is a very tricky adjustment to get right and it also drifts over time, requiring readjustment. It's a nuisance - and part of why I sold my Delphi way back when - and the table won't perform well if it's not properly setup. It is very important to use a subsonic filter and digital filtering is the only way you can do this effectively without injuring the bass. I roll off at 18 Hz 80 dB/oct. I use a Sota and a large subwoofer array and have absolutely no issues.Subsonic ("rumble") filters are a Band-Aid so if you use them you already know you have issues. They certainly can be effective, but I think the best solution is to remedy the problem at the source. It can be done - my system is essentially flat in-room to below 20 hZ. That's spooky bass with no rumble and no rumble filter. |
Usually it’s a very bad idea to “suspend” on springs a turntable that already has a built in suspension. So I am surprised that a few recommended adding a sprung shelf. The two suspensions will inevitably fight each other which could end up with positive feedback of vibration. Remember the Verrazano Narrows bridge collapse. |
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