Racquetball isolation platform perfection

Bombaywalla
Heres a pretty simple story… A friend of mine had a huge big screen, and his rack between the speakers.. Fairly large room, all wood floors, kid that would run around time to time etc… Now I said first the location of all his gear was just bad, not even center totally off center due to the big screen in the middle, and cables all over yada yada… You could hear anything picked up thru his table unless directly placed on the floor coupling it to obviously the ultimate surface in the entire room to dissipate the floor.. Sounded good right on the floor with some cushion footers! However this is not practical nor safe, so realistically a new idea had to come out of it..

First off we had pretty hi end gear, and cables going which it sounded good but not great. So my idea was he had a wall to the right of the whole thing he could move this stuff too, however with obstacles, first cable lengths, and second french doors going to another area in the house.

So long story short I did a quick cheap test.. We moved all the gear to this wall, now easily 12 to 15 foot from any speaker resonance or drivers firing, the room was plenty wide to not even have to overlap the gear over the soundstage or be in front of the path of the speaker at all on that side. Well so now stuff is moved, bought some super cheap Rat shack speaker cables, like 16 and 14 gauge for about 18 bucks 100 foot…

I knew I was not happy running 15 plus foot speaker cables vs. the 4 ft expensive cables we had already been using when the system was in the middle.. But anyway doubled up the rat shack wire to give a little better current carrying from the amp to the speakers. Bottom line, this configuration blew away anything possible having the turntable or system in general between the speakers!! Cheap cables or not made no difference at the incredble results especially now the turntable sound was exhibiting…

Nothing made this table have an issue now, techno, super heavy metal, clean and smooth as water. Its simple, either overbuild to a ridiculous degree of racks and isolation in the middle of your speakers, or take the table across the room or out of it all together!

Put the table and system on the sidewall if possible, the other plus to this is kiling off all that reflection and soundstage your losing with the gear between them. Also I suggest that leaving the amp in the middle of the speakers for short quality cables is good, and taking long interconnects to the preamp on the side of the room, you will have excellent results… Of course ultimately it is better to have XLR balanced connection from your preamp source to the amp or amps between the speakers, but in most cases if your not going to far like 12 or 13 feet it can work fine..

I do not suggest however running super long interconnects to your turntable from the phono amp, this could create some kind loss or very high capacitance. That’s why I suggest moving the entire heart of the system from between the speakers in the first place.

By the way if you note the best systems in general do not have any source gear between the speakers due to several reasons, one of them being thats the spot where the most energy is focused many times in a given room. See several links below for examples, its probably the most overlooked simple tweak of all time! Of course you need the space, thats why conventionally everybody just goes and sticks their gear in the center as its just the way they normally think about a system or see it. links below to the best and brightest. This is not a substitute for good isolation, but trust me it helps just as much as the room acoustics themselves sometimes.

http://forum.audiogon.com/cgi-bin/fr.pl?vaslt&1188907858

http://forum.audiogon.com/cgi-bin/fr.pl?vaslt&1065030431

http://forum.audiogon.com/cgi-bin/fr.pl?vaslt&1140365841

http://forum.audiogon.com/cgi-bin/fr.pl?vaslt&1169058049

http://forum.audiogon.com/cgi-bin/fr.pl?vaslt&1104944182

http://forum.audiogon.com/cgi-bin/fr.pl?vaslt&1170194197

http://forum.audiogon.com/cgi-bin/fr.pl?vaslt&1123210106

http://forum.audiogon.com/cgi-bin/fr.pl?vaslt&1094159192

http://forum.audiogon.com/cgi-bin/fr.pl?vaslt&1090183709

http://forum.audiogon.com/cgi-bin/fr.pl?vaslt&1065609917

http://forum.audiogon.com/cgi-bin/fr.pl?vaslt&1022712214

http://forum.audiogon.com/cgi-bin/fr.pl?vaslt&1036349020

http://forum.audiogon.com/cgi-bin/fr.pl?vaslt&1069279142

     

Undertow,
good story & good reminder that (if possible) not having the rack in between the speakers is ideal. Thanx for taking the trouble to provide all the system pix links.
FYI, I did *not* forget that having the rack off to the side would greatly help. In this thread Chashas1 also stated this. For me (& for many others) this is not possible at this time for a multitude of reasons that I will not mention here. I could possibily get around to doing this the next time I'm on a cable shopping spree.

This is not a substitute for good isolation, but trust me it helps just as much as the room acoustics themselves sometimes.

That's right! Your post was slightly OT but much appreciated all the same. I think that not having the rack in the middle, as you stated already, helps a lot with soundstaging. We were talking about isolation here. I'm sure that, since much of the energy is concentrated in the center, as stated by you, moving the rack out of there can be very helpful.

04-24-09: Halcro
Problem is Bombay, that you simply don't understand the physics and acoustics involved in translating 'impact-induced' sound transmission with either Structure-Bourne or Air-Bourne Sound transmission

The problem Halcro is that you cannot seem to comprehend that my knocking test is pre-empting the situation by mechanically exciting the resonances in the rack/shelf/plith/platter. In real-life, this would happen when the walls flex with the music or when there is a foot-fall or the roof shakes due to high wind, etc. Rather than induce the resonances that way, I cut thru the chase & mechanically excited these resonances w/ my knocking test. Yeah, the knocking is a worst-case scenario as the impacts are direct & probably excessive. That's OK as I believe that taking a variable to the extreme is a good way to test the what-if scenario.
It's very simple & I believe does not need any scientific study or equations like you demanded in an earlier post.
Impact-induced sound is exciting resonances just like structure-borne & air-borne sound with the impact-induced sound being a worst-case scenario. why are you having so much difficulty correlating the two w/o the walking stick of scientific equations???

Impact-induced sound is exciting resonances just like structure-borne & air-borne sound with the impact-induced sound being a worst-case scenario. why are you having so much difficulty correlating the two w/o the walking stick of scientific equations???

Bombay, there are only 2 forms of acoustic feedback applicable to audio reproduction.
Air-Bourne sound transmission and Structure-Bourne sound transmission.
Please read the attached link which has diagrams to explain the two.
http://www.avguide.com/forums/sound-transmission
Unless you are inclined to sit listening whilst a friend or relative raps on your shelves and/or turntable, Impact-induced sound transmission is not a consideration in normal audio reproduction.
To validate your testing of Impact-induced sound transmission as it applies to the regular two forms of sound transmission one needs to provide conclusive and repeatable scientific tests which demonstrate a quantifiable link between the three?
To my knowledge, there does not exist any scientific evidence which establishes a direct correlation between Impact-induced sound transmission and the other two?
Without this information, all your assumptions and knuckle rapping are about as useless as your dismissal of the role of science and physics in audio?

Without this information, all your assumptions and knuckle rapping are about as useless as your dismissal of the role of science and physics in audio?
Halcro

I never dismissed science & physics in audio! you have misconstrued my words & minced them to mean whatever you thought. In earlier posts in this thread I was talking about the physics of rotational machines with Chashas1. Did you gloss over those posts?? Obviously I know better than to simply dismiss science & physics in audio. What I said was that I did not believe that there was a need for scientific formulae for this particular test. Read my post(s) again.
Thanx for the link - I'll read it.

Unless you are inclined to sit listening whilst a friend or relative raps on your shelves and/or turntable, Impact-induced sound transmission is not a consideration in normal audio reproduction

I agree with you that it's not considered normal to have a friend knock on your rack while listening. Let me re-iterate (for the nth time) my objective of my test - I want to see if the rack/shelf/plinth resonance is excited will I be able to hear it. I really do not care how the resonance is excited just that once it's excited I want to kill it off. Also, material's resonance is only 1 freq no matter how it is excited - knocking, air-borne, structure-borne. So, I knock on the various components & check if there is an adverse sonic effect of this. If there is, I trace it & work on dissipating the resonance. Once I'm satisfied, then, I can be reasonably sure that if resonances are excited via air-borne or structure borne transmissions (as cited in the link you provided), I will not hear them.
You can do this test by actually inducing air-borne &/or structure-borne sound xmission; it's easier, more expedient & gives the same results (afterall the objective is to try to excite resonances) if one knocks on various materials & sees if they need work damping-wise &/or isolation-wise.