Racquetball isolation platform perfection

Well, sorry bomby, but you are clearly wrong in asserting that turntable design hasn't changed. You must be locked in some time warp.
I'm not meaning to be an antogonist, sorry, but rapping a table has nothing to do with how it will sound. Fremer used to do that long ago, and has now wised up.
And as for your balls, if you like what they do, fine. I had a friend in the early 80's using those, and tennis balls.
Good luck.

04-23-09: Chashas1
Well, sorry bomby, but you are clearly wrong in asserting that turntable design hasn't changed. You must be locked in some time warp.

I'm afraid I differ in this from you. I still say the fundamentals that are used to design a TT have not changed. A TT is a rotation machine & all the physics that apply to rotating machines applies to the TT during its design phase. Yes, the materials used in the TT design have changed over time but the fundamentals have not changed. That's what I wrote in my prev post & that's what I'm writing again.
I'm confident that I'm not in a time-warp but I do think that you are under a mistaken impression.

but rapping a table has nothing to do with how it will sound.

I NEVER said that I knuckle rapped my TT to find out how it would sound. You made this up!
Read my original post again!

And as for your balls, if you like what they do, fine. I had a friend in the early 80's using those, and tennis balls.

Man, you really need reading glasses! I'm not the one using balls! Yeah, I thought about using them but ended up never using them. You need to read the whole thread again & figure out who's been writing what before you make allegations.

I'm not meaning to be an antogonist, sorry

OK. thanks for clarifying.

04-23-09: Chashas1
Knuckle rapping and raquetballs are sooo 80's....
I thought I was reading a back issue of Audio.
Come on, guys, progress a little, will ya?

hey Chashas1 maybe you want to tell these words to fine folks at Ginko Audio (who make TT isolation platforms using raquetballs) & to all the users who have bought these isolation platforms & are having remarkable success with them!
http://www.gingkoaudio.com/cloud9.html
http://www.gingkoaudio.com/cloud10.html
http://www.gingkoaudio.com/cloud12.html
http://www.gingkoaudio.com/minicloud.html

(or, maybe you will write back & tell us that these isolation platforms don't work because they are "sooo 80s"??)

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??