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Coupling/Decoupling Electronics

All the posts I’m making are due to my recent purchase of KEF LS50s and my attempts to optimize them. I’m now the first to admit that little changes make a big difference. At 12” from the wall behind then, the bass gets a little muddy. At 13”, I get nice reinforcement without any muddiness. A couple of weeks ago, if you had told me that an inch would make a difference, you’d get a very skeptical look. 

Inevitably, I wandered into the coupling/decoupling, spikes/pads battle. After much reading and a lot of lessons in physics-lite, I have determined that there are too many variables at work—speakers, stands, carpets, floors—for any kind of blanket statement to be made. 

There seems to be less controversy about electronics. The word is: Isolate! Those same speakers that are producing so much vibration are a deleterious force. We must do our best to keep those vibrations away from our finely tuned electronics. 

So here is my question: Don’t electronics produce their own vibration? CDs spin, amplifiers amp. Lots of energy being produced. Like speakers, is isolating them from the world around the right thing to do? Shouldn’t that energy inside the boxes be passed off, as speaker energy is passed off by spikes?


I suspect that, like the speaker question, there’s too many variables at play for a simple answer but I thought I’d ask.


Here’s another, more mystifying question. I just traded up from KEF Q150s. Black ones can be had for $300 from Amazon. White ones—the identical speaker—are out of stock everywhere and cost $5-$600 if you can track down a pair. This seems not to be an example of an efficient market, as Adam Smith might define it. (I’m not complaining. I had white ones.) (And I think that Adam Smith’s ideas are long out of date, having been surpassed by managerial capitalism, advanced capitalism, and whatever is en vogue at this University of Chicago these days.)
paul6001
mahgister's avatar
mahgister
13,091 posts
 
I use with great success springs sets finely adjusted on top of a sandwiches of coupling/decoupling varied materials: bamboo,granite,cork,sorbothane....

I use 2 sets of 4 springs boxes dyssemetrically compressed by some heavy load damping the speakers and the 2 sets of 4 springs boxes for each speakers one set under the load and another set under the speakers+the load.... Natural timbre of instrument and minimal interference between speakers sitting on my desk.... Cost: peanuts...
djones51
4,947 posts
 
I wouldn't worry about it with LS50 speakers and digital playback. Turntables are affected by vibrations. I can't see anyone sitting around listening to streaming music through a bookshelf speaker chiming in telling you the vibrations are really messing up the amplifier and streamer. 
cd318
2,636 posts
 

@mahgister

Yes, springs despite possible accidental impact instability issues may well be the best way to go.

As you say the cost is negligible.


Richard Vandersteen on the other hand doesn't seem to like any introduction of compliance between speakers and resting surface.

I can see where his argument is coming from in regard to the loss of treble information introduced by additional compliance.  

On the other hand I would that think movement of the treble dome, which can be measured in microns, is far too small in size and mass to be affected by any form of compliance placed underneath the loudspeaker.

--------

Ask Richard

Richard, I've seen a lot of discussion about coupling vs decoupling, a lot of people suggest decoupling speakers especially on wood suspended floors like I have (also carpeted with cement board). 

Would it be advisable to use a flexible puck or something under or instead of cones with my 5 A's in that instance? 

In Richards ears I trust.


(2-15-20) 

THERE HAS BEEN A LOT OF MISINFORMATION ON FOOTERS FOR SPEAKERS. A SPEAKERS JOB IS TO MOVE AIR SO THAT WE CAN HEAR SOUNDS. THIS PRESSURE WAVE IS CAUSED BY POSITIVE AND NEGATIVE MOVEMENTS OF THE CONES AND DOMES MOUNTED INTO A SPEAKER ENCLOSURE. 

WE CAN SEE THE LARGE MOVEMENTS A WOOFER MAKES BUT THE TWEETER IS ALSO MOVING MICRONS DOING ITS WORK. FOR THIS TO MOVE AIR THE ENCLOSURE OF THE SPEAKER MUST BE HELD RIGIDLY IN SPACE OR SOME OF THIS WORK WILL BE LOST. KINETIC ENERGY CAUSED MOSTLY BY THE MOVING MASS OF THE WOOFER WILL TRY TO MOVE THE SPEAKER ENCLOSURE ANTI PHASE WHICH CANCELS SOME OF THE SIGNAL. 

ONE PAYS A LOT OF MONEY ON THE OTHER COMPONENTS OF THE SYSTEM JUST TO BE THROWING SOME OF IT AWAY AT THE SPEAKER. THE RESULT IS CANCELED DYNAMICS AND TIME SMEAR. 

SO WHY ARE MANY HAPPY WITH THE SOUND WHEN USING COMPLIANT FOOTERS? MANY SPEAKERS ARE DESIGNED DELIBERATELY BRIGHT SO THEY WILL MAKE AN IMPRESSION DURING THE DEMO BUT ONCE THEY ARE INSTALLED IN THE SYSTEM THE EXCESSIVE HIGH FREQUENCIES BECOME BOTHERSOME. 

PUTTING A COMPLIANT FOOTER UNDER SUCH A SPEAKER AND THROWING AWAY SOME OF THE EXCESSIVE HIGH FREQUIENCY ENERGY MAY BE MORE MUSICAL AND PREFERRED BY MOST LISTENERS. 

WE INSTALL 3 POINTS UNDER OUR SPEAKERS BECAUSE 3 POINTS (POINTS DRAMATICLLY INCREASE THE EFECTIVE MASS OF THE SPEAKER) DEFINE A PLANE AND ASSURES EQUALL LOADING ON ALL OF THE FEET.  


THE RESULT IS LESS TIME SMEAR, LOWER DISTORTION, INCREASED DYNAMICS AND HIGHER RESOLUTION BECAUSE THERE IS LESS FORE AND AFT MOVEMENT. (RV)

https://www.vandersteen.com/support/ask-richard

mahgister's avatar
mahgister
13,091 posts
 

ahgister

Yes, springs despite possible accidental impact instability issues may well be the best way to go.

As you say the cost is negligible.


Richard Vandersteen on the other hand doesn’t seem to like any introduction of compliance between speakers and resting surface.

I can see where his argument is coming from in regard to the loss of treble information introduced by additional compliance.

On the other hand I would that think movement of the treble dome, which can be measured in microns, is far too small in size and mass to be affected by any form of compliance placed underneath the loudspeaker.

My speakers are heavily damped (75 pounds) and with 2 set of springs for each speaker dyssemetrically compressed the advantages of the springs is not only that they isolate well but that it decrease also the negative power of internal resonance of the speakers rectangular boxes which is more impactful than the alleged compliance of the springs boxes which according to Vandersteen is supposed to decrease the highs....I obtain way better highs frequencies with this method.... No spike can beat that....Isolation from external vibrations is not all the story to tell.... Internal resonance is also a story....

I put my springs on top of varied materials in sandwich(cork-granite-sorbothane-bamboo) because my dac and amp are beside on the same desk.... It is very efficient.... Almost no vibrations to my knowledge comes from speakers or go to them, minute some unmeasurable by me anyway....My other gear is on top of the same sandwich....

In the beginning i tried 4 spings boxes by speaker like all people .... It was an improvement.... Then i read about damping tuning mass in building architecture.... That gives me the idea to tune the springs by changing the compressive force acting on one set and on the other...The only way was putting a set directly on top of the speaker under the delicately tuned damping load  weight compressing this set of springs....(we must fine  tune the load near 1% of the required mass i did it with my ears no calculus necessary) The other set directly under the speaker is more compressed because the weigh of the speaker itself add to his compression and not only the damping load....The resulting improvement was on the same scale than the first improvement proving to me that only using a set of springs under the speaker is not enough....

The dramatic change introduced by the rightly use of the 8 springs boxes for each speaker is then the key.....16 spring boxes in all but they are chinese cheap one very well made and like the Nobsound one....Under 100 bucks for the 16 boxes then not much more than peanuts for this... 😁😊😎
oldhvymec
5,101 posts
 
Points isolate in one direction. unless they are setting on a bed of springs, and then you have to dampen the springs, they will ring..
The problem is the box.. It is alway the enclosure and the width of the baffle face. Its ability to deflect waves coming BACK and waves from inside. You can isolate the internal waves but the box resonance.. That requires some thinking..  Rounded corners, panel breaks, and surface treatment inside and on the way out, is the best way. 

Springs, airbags, earthen foundation, flotation, magnetic repulsion, suspensions and ALL types of devices still leave THEIR mark on the sound... It really depends whether you like it or not.. The simpler the better for me.. Heavy, thick, quiet, enclosures work..

Remove ALL the unwanted resonance by removing the drivers from the enclosure. That is the only good way.. Everything else is a compromise.
Once you understand that you can build a DIFFERENT type of system..
Things like boundys become a lot less of a problem just like driver time alignment and phase shift. ALL the gobbledegook, like filling the room with ugly ass acoustical STUFF becomes a lot easier. I use separate narrower columns NOW.. Just works better.. It is a work in progress..
Just not an UGLY one.. 

Like I said before, "she can only be so ugly" (or he if you prefer) and they will get a bag over the head.. Put some lipstick on the bag I'm fine.

Regards
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