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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
22,631 posts
 
"I say, why not put the filter in, if it is a problem. If you don't hear it, don't worry about it."

Agree. It's not illegal. If it works for the better for you, then you should do it.

BTW the other common negative effect I've seen with rumble and other types of low frequency noise, is that even if it is not audibly disturbing to someone , the fact is it uses up significant amplifier power to produce noise. This can result in the amp clipping and damaging the speaker. Ironically, the low frequency noise usually ends up damaging the tweeter first, at least in most cases that I have observed over the years.
eldartford
4,262 posts
 
Rumble, due to turntable vibration or recorded in the vinyl has always been my second gripe about LPs, the first being HF surface noise. CDs have taken care of this problem.

Imagine my surprise to get a CD of theatre organ music (from Organ Stop Pizza, in Mesa AZ) which has what seems to be lots of LF noise. It took me a few plays to realize that this sound is exactly what you hear in the hall as you eat your pizza and drink your beer. It's the organ's air generation machinery. Once you realize that it is not a recording deficiency it ceases to be an annoyance.

In a similar vein, surface noise does not bother me when I play my LPs of Benny Goodman's 1938 broadcast recordings. Somehow it becomes part of that particular musical experience.
mapman's avatar
mapman
22,631 posts
 
Eldartford,

I am in agreement with your perspective on these things.
mapman's avatar
mapman
22,631 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).
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