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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
mapman's avatar
mapman
22,910 posts
 
Eldartford,

I am in agreement with your perspective on these things.
mapman's avatar
mapman
22,910 posts
 
Two good things (relatively) about low frequency noise playing records:

1) I find it less offensive during listening than high frequency noise

2) If you can see the woofs on speakers, you can be sure when it exists because you can see and/or feel it perhaps even easier than you might hear it.
ptmconsulting OP
1,000 posts
 
I tend to agree with you Mapman. The less I have to put in the signal path the better I feel about it and the better the transparency/musicality. I would far prefer to find a mechanical solution that doesn't alter the rest of the sound, if possible.

If not, I could still be happy with my rig the way it is. This is not a burning issue, but just an investigation into options and potential solutions.

And in this economy I am less likely to get itchy fingers and spend $ on a trial and error kit that has zero resale value (unless, of course, I DO get itchy fingers after the holidays and need a project to keep me busy).
mapman's avatar
mapman
22,910 posts
 
Ptmconsulting,

It hasn't been a burning issue for me either. It is what it is. You either live with it or there are ways to deal with it both physical (clamps, new records, CDs instead) or via signal processing (filters, etc.).

On the signal processing front, when it comes to dealing with complex signal processing issues like this, technically, a lot more can be done in the digital domain than in the analog, but it is a complex undertaking and not one I would recommend for the uninspired.
ptmconsulting OP
1,000 posts
 
And why, in God's name, would one ever run a beautiful analogue signal from a turntable through anything digital, unless they were forced to upon pain of being drawn and quartered? :-)

I think I'll open a bottle of wine tonight and listen to something nice on the old-TT.

Enjoy,
Bob
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