Spikes on tower speakers

@phil59, turn the speaker upside down get a piece of heavy duty tin foil and press it down over the spikes to protect the bottom of your speakers. Find out if the spikes have a stud that is screwed into the speaker. My guess is they do. 

Take a smallish hammer and lay the head flat on the tin foil and tap each spike from all directions to loosen it the get a Channel lock wrench and use it to unscrew each spike. Now replace then with longer spikes. Use three spikes not four!!  If he used four fill in the rear holes with plastic wood the right color and put the third foot in the middle.

When placing the loudspeaker you have to get the spikes all the way through the carpet and padding to the wood underneath. Hold the speaker steady and using a step stool have your wife press down on the speaker right in the middle with a stocking foot while you hold the speaker and spot. She could stand on it if she has to. That should set the speaker in place and you should be good to go. 

@vinylvalet. ​​@clearthinker is absolutely correct. Any movement of the speaker enclosure is distortion. This occurs mainly in the bass. Put your hand on the speaker while playing a bass heavy number. That vibration you feel is distortion. The floor to the speaker is analogous to the tonearm to the cartridge. The floor has to absorb the energy transmitted by the speaker without reflecting it back. Admittedly, some floors are better at this than others but, that is a floor problem not a speaker problem. 

All Speakers producing bass have to be anchored to the floor. Any other approach is absurd. The OPM should take this into account and anchor his speakers to the floor. If the spikes are too short to make it down to the floor then you need longer ones. If you feel uncomfortable doing this yourself find someone that is not. I would gladly do it for you if you live in New England.

@michaellent , you change the amplitude response of the speaker when you raise it off the floor and you prefer that response. Just as many people are going to think it worse! There are much better ways to deal with amplitude without disconnecting the speaker from the floor. As long as the floor is significantly more massive than the speaker's drivers it is much better to spike the speaker to the floor. This is easy to demonstrate with test signals and a measurement microphone.

@michaellent , Amplitude is essentially volume but referring to output level across the frequency spectrum. It is a essentially a different way of describing frequency response. An equalizer adjusts amplitude at specific frequencies with a specific Q.

@jtcf , The silliest thing you could possibly do to a subwoofer is put it on anything but a very sturdy floor. Put your hand on the sub playing a bass heavy number. That vibration you feel is distortion. In a perfect world you would not be able to feel anything. Some of the best subs come remarkably close if placed on a solid floor. None of these have a single driver. The Newtonian forces of a single sub driver shaking at 20 Hz will vibrate even the heaviest enclosure.