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.