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In Reply to: RE: A TT tweak posted by unclestu on June 28, 2015 at 17:07:57
someone just emailed me and asked if there was a difference between the silver dimes and the newer ones.
As a matter of fact there is. Newer coins are sandwich designs with a zinc core. It makes for better damping, I assume, but sounds duller than the older silver ones ( I have a lot of them as I always liked those Mercury head coins, but there were a few years of Eisenhower all silver issues too.
Follow Ups:
Newer pennies have a zinc core, newer dimes are a copper/nickel sandwich.Pre-64 silver coins are 10% copper.
Nickels are 75% copper (war nickels are 35% silver, no nickel).
Edits: 06/28/15
How can something with the mass of a "thin dime" affect the resonant frequency of a typical loudspeaker cabinet by more than a very tiny bit that is likely to be inconsequential and unlikely to dampen resonance (again due to the low mass)? Sorry for the long question.
It costs only 80 cents to try and if you don't hear anything you can merely pocket the change.....But in answer to your question, try placing your hand lightly on the cabinet tops while music is playing. There is always, in varying magnitudes depending on the construction, some vibration.
Incidentally Stereophile did a review of a very similar tweak, called the $1.25 tweak. I had already settled on dimes way before they published their review, BTW, several yeara prior. I believe you can find it on their website
Edits: 06/29/15 06/29/15
OK. For sure I can feel the speaker cabinet vibrating, in your experiment. Now, what would it take to significantly dampen that vibration? I submit that you'd have to sit on top of the speaker to have any significant effect. My point was and is that the mass of a dime or any other coin could not possibly dampen the vibrations inherent in a speaker cabinet in any audible way.
After the $1.25 tweak there was a company that made a plastic square about three inches high with plastic sheets that vibrated loosely. I forget their name
The concept here is simply energy TRANSFER. We are attempting "wick" away some of the energy into the air at a frequency which is not really audible. The dimes will vibrate, but not loud enough to interfere with your listening. It will thus take some of the energy in the cabinet and dissipate it in the air.
Some will use very heavy weights and report generally a slight improvement in the bass, primarily because the energy involved is the much lower frequencies. Tweeters are generally on the top and the simple dimes are quite effective for the upper frequencies, at least in my experience.
Try a heavier coin and you will hear the difference.
Could the effect you want to describe be analogized to that function of a heat sink? Your use of the word "wick" in context made me think of how a heat sink dissipates heat. If so, a larger heat sink would be analogous to a higher mass object sitting on top of the speaker.
well, yeah to a certain extent. But generally, too heavy a mass tends to over dampen the highs making a speaker sound dull.I finally remembered the device that I was referring to earlier:
Tekna Sonic
They made similar devices in various sizes: mini monitor, woofer, etc. They had some mass, but the plastic vanes, anchored only on one side of the rectangular outer shell were designed to ring ( not audibly, though).
Got good reviews and work very well: I still have a couple lying around
Edits: 07/10/15
but pre 64 were pretty much homogeneous mixes of the alloy metals. The newer ones have distinct layers.
makes a difference in resonance control
The current clad version is two layers of cupronickel, 75% copper and 25% nickel, on a core of pure copper. The total composition of the coin is 8.33% nickel, with the remainder copper.
They make the blank planchets locally here at PMX Industries.
The $1 coins are Manganese-Brass 88.5% Cu, 6% Zn, 3.5% Mn, 2% Ni .
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