Spikes and added weight for subwoofer performance?

A forward firing sub moves horizontally. For every action there's an equal and opposit reaction. Thus the cabinet is moving too, but much less because it's mass is high compared to the subwoofer cone. The higher the cabinet mass, the less movement it will have. The less movement it has the faster the acceleration the cone will have. Adding spikes and mass, will increase the effective mass of the cabinet as it will be using the floor as part of it's mass structure also.

Bright Star Audio is correct that this can transmit vibrations and your audio equipment should be isolated, but I thought using his or other's vibration control rack systems would be advantageous there.

A forward firing sub moves horizontally. For every action there's an equal and opposit reaction. Thus the cabinet is moving too, but much less because it's mass is high compared to the subwoofer cone. The higher the cabinet mass, the less movement it will have. The less movement it has the faster the acceleration the cone will have. Adding spikes and mass, will increase the effective mass of the cabinet as it will be using the floor as part of it's mass structure also.

Bright Star Audio is correct that this can transmit vibrations and your audio equipment should be isolated, but I thought using his or other's vibration control rack systems would be advantageous to use for the equipment rack.

Rives, at the frequencies involved with sub woofers, how much lateral movement do you think it would take to disturb (distort) the soundwave? I'd tend to agree with your implied conclusion that lack of coupling would cause deterioration if we were talking about a tweeter or mid-range speaker, but a woofer?

Newbee: It doesn't distort the sound wave, not in any meaningful way anyway. It's really a matter of efficiency. Imagine a cannon shooting a cannonball. If you can make the cannon really firm (say couple it to the ground) rather than have a lot of backwards kick, the cannonball will go further. It's the same when the voice coil is moving the cone, if what it's attached to does not move (by adding mass or spikes or whatever), then it will be more efficient at moving the cone.

Interesting