Subsonic Rumble Solutions

acoustat6 you must be reading a diferent post then i am. ptmconsulting posted a question based on his analog equipment with hiss tt and it's set up. also seeing that no normal human can hear below 20hz and that sound at that level is felt and he descibes the problem coming from his "speakers" and not sub. i own no vinyl music that i believe goes below 20hz. i do not listen to organ or classical music. although i listen last nite to stealy dan's "gaucho" and that could be definatly felt. l believe the rumbling he is descibing has to do with the tt set up, either in the bearing or platter or plinth with those steal screw feet and definitly is not something inherant in vinyl and that one has to settle for or mask. one of my first tt's had a similar problem. over a certain volume the tt would resinate. OH and my system sounds STELLAR, thank you very much!

04rdking,

YEs, I got it backwards I think.

I did mean "stiffer" which I believe is in fact lower compliance.

Hi Koegz, I am sure your system is capable of great sound, you will not get an argument from me there. And I assure you I am reading the same post.

I dont believe Bob#1s (ptmconsulting) issue is his tt, but the fact that he is able to reproduce these unwanted freq, whether they are subsonic (ie not heard) or rumble (pumping and audible due to its freq).

Whether this is due to his ablity to reproduce below 20hz (subsonic) at a significant spl level, or if it is from 20hz up (rumble) and his systems ability to play down to 20hz. Most assuredly both, but I dont know I am not there.

It could be a bass peak in his room which is accentuating his "rumble" problem at perhaps over a certain freq, say if he has a broad 10db peak over from 30 to 50hz.

Conversly it could be someones system is not able to reproduce 20hz and below for subsonics to be a problem. Or his system is not able to reproduce 20-40hz where rumble generally resides. As well as it could be that someone have a 10db bass null over the range of 30-50hz which is preventing them from hearing the offending rumble.

It could be that he has a very good in room response that is allowing his system to reproduce all of the noise produced on the LPs. Just as well as someone else may have a falling respose over the range that all of these problems occur at. Ie; a falling response from 50hz down, which is not at all that uncommon.

I too don't own any LPs that have music below 20hz, but all LPs do have noise below this freq, it is a systems ability to reproduce these freq which is the "problem".

You are pretty much correct that you "don't hear" these freq. Especially if you your system is not able to play that "low" or if your system can do 20hz and below, the question then becomes how loud do you listen.

I believe it has nothing to do with the type of music you listen to. Some LPs do have more subsonics than other LPs. As well as some LPs have rumble at a significant level as well. Some LPs have rumble that perhaps goes up to 30 or 40hz at a low level while others can have rumble that goes up to or even over 100hz at quite a high level, though that is rare. But is has nothing to do with the style of music.

Many of my LPs have close to zero rumble, or at least insignificant enough that it is not a problem. Though I always keep my rumble filter in at all times. Many of my LPs have rumble at a high enough level and freq, that it is an audible problem.

I believe that all LP systems would benefit from 20z (subsonic filtering). Regardless if your system is reproducing (audible) this sound or not. You do not even want your amps to be trying to reproduce this. And even a little bit in your speakers is not desirable. My 20hz filter must be kept in at all times.

I do not hear rumble on all LPs as well as Bob#1 does not hear rumble on all LPs. This sound is not coming from our tables, or we would hear it equally on all LPs when all of the LPs are played back at the same gain setting.

Your comment on the Groucho is nonsequiter to this discussion. Please tell me what you thought could be felt.

Bob

"I believe that all LP systems would benefit from 20z (subsonic filtering)"

If done right, I would tend to agree.

the kicking of the drum or the pluck of a base string can be felt as well as heard. my wife, who loves to say "i hear no diference" feels it as well. it is not a rumble but an extension of the sound. it is tight, well defined, inspiring and adds to the music. heard often in steely dan, van morrison and dire straits albums amongst others, it gives the feeling of being there. on a diferent point it is my understanding that sound under 20hz can not be heard by the naked human ear, but only felt. also with some changes to his tt the originator of this post claims to have solved his trouble. i do understand your point, just don't agree. i avoid placing anything between the source and speakers, other then the minimal required. i subscribe to the therory, less is more and try to seek it in my equipment(2 channel) set up. you seem to be more technical savy then i. notably i do not have agreat knowledge of 20hz-30khz, -3db or such, but i know what sounds good to me. i have a very mechanical type mind and see flaws in the physical makeup/desighn once i understand the workings such as in the tt in question. i do not wish to be argumenitive and insist i know all, i am certain i do not. it is just your solution goes against my listening belief that if something is off there is a reason and something is wrong in the chain and the repair is not by altering but to repair, adjust, get rid of or replace. i have a relitively large vinyl collection some are better recordings then other. it occurs to me that you probably have a sub, i do not know what your system consists of, i do not, and you are referring to sub rumble which i have heard caused by the sub trying to make sounds out side(above) it's capability. i do not use a sub because i do not like nor feel that they are true to the sound of the music, movies yes. they tend to over state or exagerate. but to each their own.