Vibration - What are the Main Sources?

@rixthetrick, no worries as I wasn't offended at all. I just didn't understand where you were coming from. No biggie.

All the best,
Nonoise

I believe the premise is that the speakers are resting motionless on the springs at a specific tension and the function of the spring is to isolate/dissipate vibration.

@perki - The minus K approach would require some engineering based upon some pretty complicated math.

If you’re going to order springs for your speakers, some specifications I have found that may help you. (specific to compression springs)

• springs should have approximately 50% compression under load, this aught to allow for the highest amplitude and frequency range of isolation.
  
• the diameter being either greater than or equal to the height of the spring under load will help it to deform along it’s length rather than simply twist and collapse under the load.
• the least number of springs (usually three) the better, and use the same spring rate to level the mass supported, move the springs to positions that level the load. Do not change the spring rates to level the load if it can be avoided, move the springs around the center of gravity.
  
• 4Hz isolation or lower if possible (minus K have some that do 2Hz I think?)
• loads that are tall and skinny (like floor stander speakers) will be able to move when they may be bumped, moving their center or gravity over the base, where gravity will have it’s way with them. Broaden the base so that is much less likely to fall and get damaged
  
• the substrate supporting the springs is another factor to consider, the more the springs deform to the load’s movement the better

If you consider the speaker cabinet to be somewhat like a very rigid balllon, the lower frequency driver will create a high and lower pressure within the cabinet. This will push and pull at the walls of the cabinet, much like pulling and pushing a post, which at the right frequency with the right amount of force will move back and forth.

These high and low pressures in the enclosure will energise the nodes of the cabinet. Nikola Tesla is an interesting read, and Mythbusters did an excellent episode with a bridge regarding that science. The walls of the enclosure will move in much a similar manner to a balloon. My speakers have been made from composite materials, lined with steel plates, and they move, their nodes can be heard by wrapping my knuckles on them.

Instead of thinking of a speaker enclosure as an entirely rigid structure, consider it to be an ever morphing shape energised by the drivers during playback, especially when played loudly. So instead of it moving on it’s base, the idea of springs is to keep the center of gravity as virtually stationary as possible, trying to keep the drivers held in relative space to the listener.

I believe the premise is that the speakers are resting motionless on the springs at a specific tension and the function of the spring is to isolate/dissipate vibration.

Dissipation of cabinet frequencies can be better achieved by using TMD (tuned mass damper) technology. This technology is used in modern high rise buildings with great success.

https://dspace.mit.edu/handle/1721.1/38947 If it's of any interest?

Basically a TMD for a speaker will allow it to be decoupled from the cabinet, and yet reactive to the vibrations of the cabinet, so that it can cancel out the vibrations by being out of phase in it's motion to the cabinet.

So the springs from below are being deformed by the cabinet, transferring kenetic energy to heat through the springs, and the sprung mass on top moving out of phase with the cabinets to oppose the energies each see from each other.

I know, it may sound absurd, however, in person it sounds truly superb.

rixthetrick,

Thanks. The springs are for my TT, mostly as an experiment :)

Hoping the spring retailer will help me figure out a spring rate that makes sense.  And yeah, height/diameter is important. Don’t want stuff swaying :)  And I’m thinking to start with spring rates such that there is an equal force required lifting up or pushing down to have it move the same distance. As close to floating as possible.

And agree, the math behind K Minus is above my pay grade. 1/2hz and 1hz, crazy low they go. 
It’s fun to play with this stuff. Especially when cost is low. Added bonus of course, when it works.