Subwoofer rumble issue


I’m having a hard time solving a problem that seems to come and go. My subwoofer will rumble uncontrollably when playing records at a higher volume. If I turn the volume down sharply it goes away but when I creep the volume back up it comes back. I’ve tried isolating my turntable as much as possible with diy books, isolation feet, etc. (I don’t want to buy an expensive isolation platform unless that really is the issue.) Any thoughts on what I can do to fix this? Thx!
paulgardner
Hi Paul

I just added a Clearaudio Ovation to my system this week and I to am having some feed back issues. Needless to say I am very disappointed, but it is what it is. Mine seems to be feeding back approximately at 30hz and 120hz at volumes ranging from 85 to 95 db.

Some of the contributing factors that I think are helping cause my issue is my listening room is very small at 14 x 10 x 9, located on the second floor of a 122 year old house and I have the turntable sitting on a very cheap fiberboard end table along an outside wall about 3' feet in front of my left sub.

I placed some anti vibration pads under the feet of the turntable (available from amazon for about $10 to $15 for a four pack) which helped reduce if not eliminate the feedback at 30hz and added a little more detail to the recording. I use an active crossover to integrate my subs that has a digital graphic eq built into the inputs that I used to reduce the 120hz output of my system thus eliminating the feedback.

My next move is to build a prototype table out of 2 x 4 pine so I can relocate the turntable so it is above and slightly to the rear and left of the sub. If this works I will then have Saluda River Audio Stands build me a permanent table out of maple and walnut. 

Also when you said that all hell broke loose when you switched polarity on your sub I believe that was when your subs were actually in phase, at least with the turntable.


What kind of sub ,or how cheap is it made.
Buy the svs sb 3000 with control app for under $1k delivered 
And free shipping and 60 day audition  nothing better even at $1500 plenty of awards !!
It is  s Must ,saying what brand,and model it is cheaper ones 
Has minimal control small amplifiers, magnets and pole pieces
As well as cabinet construction all important factors 
How to you adjust it ?  The SVS 3000 line SB with app
For just UNDER$1K 13 inch aluminium driver  beat my  $1500 JL Audio in every respect
The split coil poll piece  works for great bass even at low volume
And the app works great . #1 sub and buy of the year. 
He already told us what brand and model the subwoofer is, a REL T9i.
Buy the svs sb 3000 with control app for under $1k delivered
Buying a bigger and more powerful sub is not going to fix a turntable problem.