By Wilde Becker. Speaker Stands. At Tuesday, July 30th 2019, 19:08:06 PM.
One of the roles of an effective speaker support is to prevent such vibrations from being transferred into other structures, such as wooden floors, desktops, shelves or mixer meterbridges. It should also hold the speaker as firmly as possible, to reduce movement due to the action/reaction effect.
Thus, the sand provides dampening, but it also prevents the stand from ringing when it’s excited by the right frequencies – another handy little add-on.
Many stands come with a compartment dedicated to sand and similarly heavy and well-damped materials. And there’s method in the madness. You see, the speaker plays music by moving its drive unit in and out to create sound pressure: when the drive unit pushes outwards, it creates sound pressure, but when it moves inwards it pushes the entire speaker backwards.
All that unwanted movement can colour and distort the sound. We do our best to prevent vibrations by adding bracing to the cabinet, but that doesn’t really help with the movement.
The theory is that the mass and spring characteristics are chosen so that the resonant frequency of the combination is well below that of any frequency they’re likely to be asked to isolate. For example, if the lowest note a speaker can reproduce is 30Hz, then the resonant frequency of the supporting platform needs to be well below that — perhaps just a few Hertz or less.
Furthermore, in accordance with Newton’s third law of motion (each action has an equal and opposite reaction), whenever the speaker cone moves in one direction it will try to push the speaker cabinet the other way.