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In Reply to: RE: Hey, Neutron, when ya gonna give up on the logic of the 1980s? posted by geoffkait on May 22, 2007 at 09:25:41
Ethan made a claim, you diverted..simple.(yah, I paid attention)..
The fact that somebody produces excellent audio product doesn't mean he knows what he's doing w/r to cables..
Doesn't mean the opposite, either.
Cheers, John
Ethan made an incorrect claim. I corrected him. You diverted. You're just being argumentative. I realize here it is only Tuesday..:-)
geoff: ""
Ethan made an incorrect claim.""He did? He called to task the statement that a sound producer of talent was the cat's meow when it comes to the choice of a cable. He questioned the invokation of a gentleman of "authority" (Gilmore) to lend credence to a position.
You diverted from that, and try to claim all of science as "authority". Ethan's remark was with respect to Gilmore. You gotta read slower..:-)
And please stick to substance, not fluff.
geoff: ""
You're just being argumentative.""Moi??? Shirley, you jest...I pointed out your failure to follow, and failure of substance...nuttin more, nuttin less.:-)
geoff: ""
I realize here it is only Tuesday..:-) ""As opposed to somewhere else where it is not Tuesday???
Long time no joust, geoff...How's life treating you?
Finally got an active platform to go under 100 nanometer vibe in an industrial enviro..this active cancellation stuff is neat, albeit weird..
You ever measure your platforms with geophones?
Cheers, John
If your argument is correct maybe we should abolish peer reviews, as the expertise of the peers will be called into question -- Appeal to Authority. Might not be such a bad idea. :-)
Under 100 nanometers? At what freq?
Are geophones anything like ears? :-)
geoff: ""
If your argument is correct maybe we should abolish peer reviews, as the expertise of the peers will be called into question -- Appeal to Authority. Might not be such a bad idea. :-)""If everything you submit is rejected, I could certainly understand your position. Luckily, that has not been my experience.
The beauty of peer review is the ability to discuss with the referees the salient issues. It's never a case of "I don't like it, and I'm an expert...it's outta here", but one of additional resources looking for clear and concise arguments. Having experience on both sides of the peer review process, I have no problems with it. Course, my experience is not with the small potato guys like the AES..Nor do I attempt to submit completely unsubstantiated, unscientific, untestable claims or assertions. The peer review process is good for culling out the garbage.
geoff: ""
Under 100 nanometers? At what freq?""Sigh...didn't I say geophones? I thought you knew this stuff? :-)
geoff: ""
Are geophones anything like ears? :-) ""Yup, just more sensitive. And, waaaay more sensitive than carts on turntables..They pickup vocal induced vibrations on a 15 ton granite table.
And more sensitive than the piezo 'ducers and the laser 'ducers.. Unfortunately, the final app is inside a 4 tesla magnet at 1.8 Kelvin, with the final mass near a kilo-pound..so, geophones (which are a coil/magnet combination), cannot be used in the high field region. (at least there are no difficult aspects to it)...:-(
Cheers, John
You said you got a platform to go under 100 nanometers and I asked what freq. Seems like a straightforward question to me. When you get that contraption to work for audio apps let me know.
~ Geoff
geoff: ""
You said you got a platform to go under 100 nanometers and I asked what freq. Seems like a straightforward question to me. When you get that contraption to work for audio apps let me know.""
Silly rabbit. Google "Geophone". Everything you ask about can be found quite easily..
Styles range, internal resonance anywhere from .2 Hz up to about 12 hz.
Bandwidth ranging from resonance to between 100 hz and 500 hz.
Sensitivities up to about 30 volts/meter/sec.
Am I supposed to do all the work for you??? I thought you made active isolation platforms..what in the world do you use as the active pickup element for the neg feedback???
Cheers, John
I make passive types, including world's only single air spring device, well below 1 Hz, 6 DOF. Active types are for chumps. :-)
geoff: ""
I make passive types, including world's only single air spring device, well below 1 Hz, 6 DOF. Active types are for chumps. :-) ""
Great. Let me know when you make an air spring that works at liquid helium temperatures. I'm not fond of trying to support anything on solid nitrogen or oxygen ice...:-)
How'd you measure your final product? A stopwatch?
Geophones would make short work of your product, especially outgoing QC.
The active "chumps" are significantly more advanced than anything you have..but I will admit they are also hugely more expensive.
Cheers, John
My single air spring platform out-performed (sonically) a Halcyonics $9K active system. It wasn't really that close. So all is not necessarily well in technical land. :-)~ Cheerio
geoff: ""
My single air spring platform out-performed a Halcyonics $9K active system. It wasn't really that close. :-) ""
Good for you. How far down did it suppress vibes? What bandwidth? What measurements? Or was it...just by ear?
Sheesh, the low price stuff..$9K...like I said, the big guys are a heck of a lot more money..geeze, I buy motors that cost that much..luckily, it's not out of my pocket...:-)
Cheers, John
" buy motors that cost that much..luckily, it's not out of my pocket...:-)
"
I guess that is pretty much how it goes when dealing business to business. I decided once to make a SOTA turntable for myself so naturally the first thing I looked into was the motor. Now I said to myself that I need a truly zero cogging, constant torque motor. Then I found some high precision rotational stages with a zero cogging motor as part of the platter itself. Add to that they had magnetic bearings and very flexible speed range. Prices for this platform started at around $15,000 + another $3000 or so for the controller. Then I looked only at a motor of that type, $10,000 + $3000 for the controller. Gulp!
I was recently talking with guy from Australia who makes this ultra expensive Contiuum Caliburn turntable ($90,000 retail...Yikes). He told me that they spend $8000 for the motor alone on that design. A year ago I would have laughed and said there is no way a single electric motor can cost that much. Now I know better. If you want to make a consumer product with real research grade parts it would cost a fortune.
I was also looking into making equipment racks from optical breadboards and research grade elastomeric feet. The specs were very good and it would have made superb vibration control. However; a three shelf rack woud have cost ME over $3000. Now think of trying to make a commercial product? Not too many audiophile takers for a $12,000 rack but in my lab in grad school this would have been purchased without batting an eye (hell we had full blown honeycomb laser tables on air suspension that were nearly $50,000 and lasers for over $500,000 so $12,000 was no big deal).
As I said, Nimbus is a 6DOF sub-Hertz device, cost sub $1K. Resonant f is as low as 0.5 Hz and as high as 2.5 Hz depending on direction of interest. Promethean is mechanical spring device w/ specially fabricated springs, scalable so very high loads can be isolated. Resonant f is below 2 Hz in 4 directions. Promethean can be made to outperform Nimbus with a little attention to detail. :-)
Test of Nimbus vs Halcyonics was by ear of a customer. On paper, Halcyonics should have won. I too have seen some very elaborate, expensive iso systems; fortunately I don't have to compete with them. :-)
~ GK
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