Racquetball isolation platform perfection

Bombaywalla
If you hit yourself in the head with a hammer do you feel it? If I hit your turntable or stand holding your turntable do you think its gonna feel it and your gonna hear it thru the speakers? OF COURSE! However if I hit the wall across the room with the hammer now will your turntable feel it, will it amplify thru the speakers?

This was my point use the source of speakers to induce some kinda airborne or vibration in the room structure, not smacking it with your hand, this is a totally different induced action. I mean of course if you tap on your turntable with a pen you will hear the ticking thru your cartridge and amplify it with the speakers, but are your speakers that are not physcially touching even with heavy bass making the same "Knuckle Rapping" sound thru your system? No because unless you are literally bouncing your woofers into your turntable stand to physcially contact it like you are with your hand your really proving nothing right?

04-24-09: Chashas1
Thanks, I am delighted to be forgiven and dismissed all in one paragraph.

glad you noticed & ack it!

good wall shelf will have less of a sonic signature than the tweeks you have been suggesting

I never denied that. All I said was that a wall-shelf also has a sonic signature. It might be less, it might be more. Read my post again! Man, you REALLY need reading glasses & your comprehension skills are pretty poor - you repeatedly keep miscontruing my words & then apologize in your next post! What a guy.....

quit beating on your equipment, you're proving nothing...

well, that's your opinion. You hold onto that. I don't see any evidence as yet that my test is fallacious. I might not have proved it in scientific terms but that does not mean it's wrong. Not everything in audio has a scientific backing & that does not mean that it's not right or that won't work in audio.

for heavens sake spare us your attempted pseudo scientific justifications

dude, you are in a pseudo-scientific explained hobby! if you didn't know that, now you do! More than half the things that you believe in audio are pseudo-scientific, psycho-acoustic, etc! While my test might have a scientific background but it does not mean that it's wrong or won't give you an idea of isolation. Just because it's not proved does not mean that it's disproved.

I hit your turntable or stand holding your turntable do you think its gonna feel it and your gonna hear it thru the speakers? OF COURSE!

No, Undertow, if the rack & TT is built well then you will NOT! That's the point I'm trying to make.
If you know a friend/dealer/acquaintance try this on some well-built rack like a Mapleshade Samson, Grand Prix Monaco, HRS. The knocking does not get thru to the speakers. Also try this with a well-built TT like a Micro-Seiki, HRX, Rockport, Goldmund. Again, the knocking does not get thru even when you knock on the platter. The top-end racks & TTs are made with far more inert material than the less expensive units but (& this is reason to tweak & DIY upgrade) with some work in the right areas it is possible to (significantly) improve the less expensive units. That's precisely what Timtim was doing & sharing & that's where I was going too.

the source of speakers to induce some kinda airborne or vibration in the room structure....
....but are your speakers that are not physcially touching even with heavy bass making the same "Knuckle Rapping" sound thru your system?

thanks for the clarification. I didn't understand what you were trying to say the 1st time around.
I agree, this is another good test - get the speakers to flex the sheet-rock walls & see if that couples into the rack & gets picked up.
This would again highlight how well (or not) the rack is decoupled to the floor & how well it is damped.
When the walls flex they induce resonances in the rack & these travel to the TT & get picked up.
Another test that I have used is to jump on the floor near my listening chair which a worst-case scenario of foot-falls or running across the room. If you have children this is definitely happening while you are listening. Again, this induces resonances in the rack that get/do not get picked up.
What my knocking test did was simply bypass all these resonance inducing mechanizms & get directly into inducing the resonances in the rack by knocking on it. The idea is to induce the resonance - flex the walls with the speakers & get that to couple into the rack or knock on it. Yeah, the knocking might be an extreme case but it does give you an idea what's happening. Taking variable to the extreme is often (not always) a good way to check out a "what-if" idea.

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.