Subsonic Rumble Solutions


I know many of you have tried to address this issue. Short of buying or building a subsonic filter (that will/may negatively affect your transparency) - what methods reduce subsonics (meaning the pumping of woofers and subs when a record is playing)?

My system:
I have a DIY VPI Aries clone with a 1" thick Corian plinth, a Moerch DP6 tonearm and Dynavector 20X-H cartridge. This sits on a maple shelf. The shelf sits on squash balls. The balls sit on another maple board floating in a 3" deep sand box. All this on a rack spiked to a cement floor. The phono stage is a Hagerman Trumpet (no built in subsonic filter and very wide bandwidth). I use the 1 piece Delrin clamp on the TT. Yes, I clean records thoroughly and there are no obvious warps, especially after being clamped.

So my isolation is very good - no thumps or thwacks on the rack coming through the speakers. But if I turn the sub on I get that extra low end pumping on some records that hurts my ears. Mostly I leave the sub off when playing vinyl, but I would like to use it if possible.

There was some brief discussion of this on Albert Porter's system thread. I'm hoping to get more answers here.

So ... what methods have you tried to reduce subsonics that you have found effective?

Thanks,
Bob
ptmconsulting

Showing 4 responses by markpao

Hello everyone, I also am experiencing, what I would consider, severe sub sonic woofer pumping. I hear no affect to the music and no noise whatsoever. It seams like many here are willing to just put up with it, which I have no problem with. Is anyone else here concerned about doing damage or premature wear and tear to your woofer and/or sub woofer from all that constant movement?
I just received a pair of those 20hz FMOD RCA filters. Does it matter where I connect them into my system? My TT is connected directly into my pre amp. I'll post my results.
Hello Acoustat6 and all,
First off let me make it clear that I do not have the experience that most others here have as I am a newbie making a re- entry into analog. Yes, I did receive the 20hz subsonic filters and installed them at my pre amp out. There was no question that the woofer pumping was reduced, but not gone. I also made a cartridge change to see if that would also help. I went from a Shelter 501MKII to a Clearaudio Concerto. The reason for the change was because there has been some talk that the Shelter is not a good match for my VPI JMW9 Signature arm and this could be part of the "woofer pumping" problem. So I went with something that worked better mathematically. I will say that I didn't see ANY change for the better or worse with this cartridge change. Maybe I should have left the calculator in my office? I hope this helps.