Racquetball isolation platform perfection

Okay, so here is what I want to know… knuckle rapping cannot be very well proven to tell you anything with a turntable isolation. However my suggestion is this, first anything physically "Knocking" on something attached to your cartridge will most likely feedback the sound thru your speakers..

However are your speakers playing in the room doing it self induced via airborne or not? In otherwords here is what the real freaks can do to test this, go and buy a 50 or 100 ft roll of 12 dollar 16 gauge speaker wire from Rat shack or wherever… Take your primary speakers out of the room leaving your whole system in place ready to "Rumble" turntable and all…

With these speakers now out of your room, put a cheap pair of speakers or a boom box in place of those speakers…This has to be on ANOTHER system or Boom box source.

Hook up your primary speakers back to your amps in that room still with your turntable as the source using the long speaker wires across the house.

Now Play the boom box totally on a separate system while your Vinyl rig is on and needle down just not playing an album so that your primary speakers you hooked up now on your main system across the house is not playing a signal… Remember your whole primary system is up and running just as if you were in the room with it playing music, however the music is coming from another system not the same one your evaluating the sound from your turntable on. Go and see in the other room if your primary speakers are actually picking up any noise from the cartridge…during this totally separate system playing.

Can you hear the music coming thru your primary speakers hooked to the turntable that is not playing anything in the other room? Can you hear any "Thuds" or "Knuckle" knocking type sounds? If no then this is just physical forced wives tales about the knuckle rap test… If you hear music however like if your cartridge is a microphone? Well this is probably the real feedback, and best thing is to put a like Isolation box around your turntable like I have using some basic acoustic wall foam in a nice little wall structure to just absorb the reflections. Not sure if you will ever get rid of sound like this just because your turntable base is inert to all vibrations or not, I am sure it will help, but feedback would still obviously go back into the cartridge unless your turntable is in another room from your speakers playing entirely. I am interested in the results if someone tries this!

Also results of before and after "Ginko Cloud" or Solid maple platform would be good, so lets say you do hear all this noise on your primary speakers that the turntable is picking up in the other room, does putting it on the cloud or maple stand eliminate or help it? Oh and still without a record on the player playing I am sure this could be a good test then turning on your motor as well to see what happens further.

04-23-09: Undertow
Okay, so here is what I want to know… knuckle rapping cannot be very well proven to tell you anything with a turntable isolation.

Undertow, why not??

first anything physically "Knocking" on something attached to your cartridge will most likely feedback the sound thru your speakers..

not necessarily. if the TT isolation is good any knocking that excites any resonances should get dissipated (if your rack is damped, etc) or decoupled (if you have brass cones, roller-blocks, squash balls, etc) from the TT thereby disallowing it to get to the TT in the 1st place.
(I think the only place where this would not hold is if you knock on the LP itself when the stylus is in the groove).

However are your speakers playing in the room doing it self induced via airborne or not?

The knocking is not creating any significant air pressure changes to modulate the drivers & the speaker terminals are connected to the amp. The amp is on during this test thus the primary input signal feed to the speakers is an electrical feed from the amp output.
so, how are the speaker drivers modulating via airborne if one is knocking on the rack/shelf/plinth, etc??

Sorry, Bomby, didn't mean to misconstrue your words.
--I believe turntable design has truly changed through the years. Yes, it's still a rotational platter, yet, the ways to make it spin are everchanging.
--To all you table rappers out there, stop it. It proves nothing. Plus, I'd hate to have you damage your cartridge.
--To all Gingko owners or diy-ers of balls, your product and method can be fine, but not always, not for every situation and product. There are many ways to isolate--cones, points, balls, tubes, sandboxes, air, wood cubes, etc. Many will do a great job of isolating, and of giving support. Not all will "sound" great in a given situation. You may isolate the hell out of your item, but what if it does something to the sound as well? something not good?
--My opening glib comment was just that, these things have been going on for years--years! But I would never be a buzzkill for someone who's taking the interest to try and improve their system. We all start somewhere. For a lot of us it was the 80's.
--Apologies to Bomby.
--I know it's fun to experiment, but why not just use a wallmount if you're trying to isolate something? If that can't do it then you are in serious need of a solution.

Hey Chashas1,
thanx for the clarification & apologies.
Looks like agree to disagree on TT fundamentals. That's fine with me as we each are entitled to our own opinions.

To all you table rappers out there, stop it. It proves nothing.

I'd like somebody to explain why this is not a good test. Right now those who oppose it are saying "this is not a good test because we say so". I'd like some explanation better than that. I claim that knocking on the rack/shelf/plinth/sandbox, etc excites resonances & one can hear thru one's speakers how well these resonances have been damped before the cartridge picks them up.

Sure every tweak has its sonic signature & that applies to the wall-shelf as well! Your words seem to imply that the wall-shelf has no sonic signature but that's not true. I think that all the tweakers are fully aware that when they undertake a tweak it might not work out & that their effort might be wasted. Goes w/ the territory.

Many times having a wall-shelf is simply not possible for a myriad of reasons - looks too ugly, studs too far away, spouse will not allow it, not enough space, etc, etc. So, the wall-shelf cannot be a panacea for many. Certainly you do not think that these people are sunk???

Looks like we need to part ways on this isolation idea as you certainly subscribe to some other idea(s). That's fine with me.

"I'd like somebody to explain why this is not a good test."
"I don't have any evidence at the time of writing this post so you are free to dis-regard my post re. the knuckle rapping test & carry on w/ your life.
I'm afraid that I do not have scientific evidence, etc for every tweak that I do. If I were a man who did every tweak only after I found scientific evidence I would most likely not be in this hobby."

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 and as you say, you don't really care?
Yet you now want us to tell you why your 'rapping' test is irrelevant?
Just go ahead and enjoy yourself....but for heavens sake spare us your attempted pseudo scientific justifications?