Understanding Coupling/Decoupling - with particular reference to loudspeakers
- Thread starter garylkoh
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Hi Greg, unfortunately, there is no one right answer - that is why I tried to give as much information as possible so that readers can try out various solutions with their own loudspeakers. I said that I do not like viscoelastics because of the out-of-absolute-phase action/reaction. It smears the time/phase coherence of the music. Elastics are OK in some applications.
If the stand had spikes down to the wooden floor, and then spikes up to the speaker on the top of the stand, that's an effective coupler. But the stand will resonate, and then you have to consider the Q and resonant frequency.
Placing the 20lb weight on the speaker was a good idea for making the spikes couple better.
If you glued the concrete slab to the floor, and glued the plywood to the concrete slab, with that 200lb speakers, you might have already coupled. But it will depend on the friction between the speaker and the felt, and how the felt is attached to the plywood. There is some possibility of creep.
Just remember that for every action, there is an opposite and equal reaction. A woofer cone that is 0.2lbs going forward 1 inch may move the speaker cabinet back 0.001 inch - which on the scale of things may distort the output of the tweeter. But may be eliminated if you have good coupling between speaker and the thin felt padding.
If I may be so bold to throw in another point of view:
If I were Greg, I would try four small beads of Blu-Tack under his mini speaker at the extreme point of each corner, replacing the upward spikes, and add any extra weight he possibly can to the stand, so long as it was solidly bonded to the stand. What I did was just add passive, paper based weight on top of speakers, made a big difference in my case.
If I were rrbert I would simply try those same four beads, but bigger, under the corners, "gluing" the speaker directly to the hardwood.
Frank
If I were Greg, I would try four small beads of Blu-Tack under his mini speaker at the extreme point of each corner, replacing the upward spikes, and add any extra weight he possibly can to the stand, so long as it was solidly bonded to the stand. What I did was just add passive, paper based weight on top of speakers, made a big difference in my case.
If I were rrbert I would simply try those same four beads, but bigger, under the corners, "gluing" the speaker directly to the hardwood.
Frank
First I want to thank Gary for the time he spent doing this. Thanks Gary! 
I read everything very carefully, with the utmost attention and passion.
And I was delighted in my readings.
Because I had a very long day, again, today, I'll reserve some of my comments for another day.
But I am very excited at the new prospects. ...And I got ideas too...
Bob
P.S. Wow, what a cool thread! And I am also surprised and amazed at some member's speaker weights! And I luv concrete floors! ...So much great potential.
I read everything very carefully, with the utmost attention and passion.
And I was delighted in my readings.
Because I had a very long day, again, today, I'll reserve some of my comments for another day.
But I am very excited at the new prospects.
...And I got ideas too...Bob
P.S. Wow, what a cool thread! And I am also surprised and amazed at some member's speaker weights! And I luv concrete floors!
...So much great potential.
Blu-tac, as I mentioned, is a good coupler at audio frequencies. Hence, Frank's suggestions will be good for Greg and rrbert situations. I would add that blu-tac must not be used just pulled or cut off the pack. You have to pull and knead it until it warms up and softens and becomes more sticky. This deforms the molecules to their viscous state. Then, while they are still warm and soft, put the four beads as little balls on the corners of the loudspeaker/stand interface, and press down until they couple.
The molecules will pull together as they relax and couple the speaker to the stand even better. Coupling at the molecular level!!
Yes, I think so. Until I designed all my speakers with their own suspension systems, I had great results with the FIM ball/cup - but I switched out the ball they supplied with a tungsten carbide ball. With equipment, I also used ceramic and ruby balls.
Few TIPS.
If I may Gary, just some quick tips that perhaps some of you might already know:
* Spikes: Arrow point heads (very inexpensive at sporting goods stores),
and you can even use them under some of your electronic components.
{They come in various sizes and lengths.}
* Isolating Feet: Squash balls cut in half, for your components like CD players, etc.
* Speaker's Outriggers: Two pieces of solid decorative wood that you screw under your speakers (four brass screws total), and spikes at the ends (arrow point heads). ...Helps Speaker's Stabilization.
* Speaker's Shock (Music) Absorbers: Rubber washers that you install between the spike and the speaker's bottom (or component's bottom).
* Audio Shelves' Vibration Isolators: Spikes, or Blue-Tack.
*** Coupling & Decoupling: EXPERIMENT. ...And use common sense.
P.S. I luv Acrylic resin (slabs); many beneficial audio uses...
If I may Gary, just some quick tips that perhaps some of you might already know:
* Spikes: Arrow point heads (very inexpensive at sporting goods stores),
and you can even use them under some of your electronic components.
{They come in various sizes and lengths.}
* Isolating Feet: Squash balls cut in half, for your components like CD players, etc.
* Speaker's Outriggers: Two pieces of solid decorative wood that you screw under your speakers (four brass screws total), and spikes at the ends (arrow point heads). ...Helps Speaker's Stabilization.
* Speaker's Shock (Music) Absorbers: Rubber washers that you install between the spike and the speaker's bottom (or component's bottom).
* Audio Shelves' Vibration Isolators: Spikes, or Blue-Tack.
*** Coupling & Decoupling: EXPERIMENT.
...And use common sense.P.S. I luv Acrylic resin (slabs); many beneficial audio uses...
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Thanks, Bob. I love acrylic too - for many reasons.
Squash balls are wonderful - leave them whole for heavier equipment.
Squash balls are wonderful - leave them whole for heavier equipment.
...And Squash balls come in various density too.
...Strength pressurization; with Yellow, Red or Black dots.
Yellow being the softer ones, and Black the harder ones.
...Strength pressurization; with Yellow, Red or Black dots.
Yellow being the softer ones, and Black the harder ones.
From my fuzzy memories of my younger days playing squash - soft to hard: yellow, blue, red, white, double white.
Under my Rega 3, I ended up with blue front left, double white rear, white front right. Because the feet had a hole in the middle, they centered quite well and the turntable hardly fell over. But then, I didn't slot the dust cover on as I thought the lid made things sound far worse.
Under my Rega 3, I ended up with blue front left, double white rear, white front right. Because the feet had a hole in the middle, they centered quite well and the turntable hardly fell over. But then, I didn't slot the dust cover on as I thought the lid made things sound far worse.
Didn't Winston have John T. perform such an operation on Winston's Avalon's? I would have paid to see John's face while he was drilling the holes.
Just to share some of my recent readings...
We all know about the benefits of decoupling the motor from the plinth of a turntable,
and also the effectiveness of a well-damped, ultra-low-resonnance plinth, as well platter.
And we all know that some of the best & most expensive turntables use acrylic in one of two (or even both) parts of the above.
...Clear Audio for example, from Germany.
* Welcome to the VPI Classic 3 turntable ($6,000) whose motor is integrated into its plinth.
- The AC synchronus motor interfaces with an 18-lb aluminum platter damped with a stainless-steel disc bonded to its underside.
- The plinth is made of a plate of machined aluminum (1/2"-thick)) bonded to a steel subplate (1/8"-thick) which is itself bonded to MDF (2"-thick).
- The platter material is damped aluminum, which can be more precisely machined than acrylic, and is more easily damped, more resistant to changes in temperature and humidity, and more dense.
And according to Harry Weisfeld (VPI founder and designer), and Michael Fremer (turntable guru, audiophile, and reviewer); it sounds better than acrylic.
-> Full review in the October's issue (2011) of Stereophile.
We all know about the benefits of decoupling the motor from the plinth of a turntable,
and also the effectiveness of a well-damped, ultra-low-resonnance plinth, as well platter.
And we all know that some of the best & most expensive turntables use acrylic in one of two (or even both) parts of the above.
...Clear Audio for example, from Germany.
* Welcome to the VPI Classic 3 turntable ($6,000) whose motor is integrated into its plinth.
- The AC synchronus motor interfaces with an 18-lb aluminum platter damped with a stainless-steel disc bonded to its underside.
- The plinth is made of a plate of machined aluminum (1/2"-thick)) bonded to a steel subplate (1/8"-thick) which is itself bonded to MDF (2"-thick).
- The platter material is damped aluminum, which can be more precisely machined than acrylic, and is more easily damped, more resistant to changes in temperature and humidity, and more dense.
And according to Harry Weisfeld (VPI founder and designer), and Michael Fremer (turntable guru, audiophile, and reviewer); it sounds better than acrylic.
-> Full review in the October's issue (2011) of Stereophile.
Here's the FIM ball/cup: http://www.firstimpressionmusic.com/product_p/model 305-4.htm
The Rollerblocks are the same sort of thing, so are Aurios, etc. They all operate under the same principles. There are also a lot of different cone-ball designs that try to achieve both, and then there are the encapsulated ball-bearing designs. Every design operates somewhere in the continuum between coupling and decoupling. If you look at one using the principles I outlined, you'll also see for yourself how they operate in the horizontal and vertical planes.
My objective for this thread was not to provide a comprehensive answer but just to open discussion.
I can tell you that switching from the plastic/ss platter to the all Al platter on my Ref. Super Scoutmaster/Rim Drive made all the difference in the world. Simply put it sound more tape like: dynamic, clean and great low level information.
Remember the first tt that HW manufactured used an Al platter and was quite thoroughly panned by HP in the pages of TAS. HW quite vociferously disagreed with HP's conclusions arguing that every LP made was mastered on a massive Al platter. Guess it's rediscovering the wheel.
I think that the plastic platters were great in the old days since their mellow sound compensated for the edginess of the electronics of the day. Now with gear becoming far more neutral, this coloration is becoming more evident. Isn't that the way of high-end? Improve one area and find a problem elsewhere?
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