Why Anchor Speakers?

Since we're on the subject of vibration tweakage, should speakers be anchored to the floor? If so, why? My speakers are on stands which rest on carpet, and I am considering spikes which will anchor the bottom of the stands through the carpet to the flooring. Should I do this? What should I expect to hear differently?
I do not feel you get the full dynamics and soundstage with speakers 'floating' on the carpet. You may need to experiment with different types of spikes or cones to find the right match. There are numerous entries in this forum on the topic, you can even search by your speaker type. I use Walker Valid Points which are placed on Walker dics. I have cut out the carpeting for the dics for direct contact to the floor... for which me and my sound room have been banished to the basement! The WAF ( wife acceptance factor) should be considered in the interest or marital harmony before you begin cutting up the carpeting.
Higher frquencies emitted by the tweeter have extremely short wavelengths.The inertial effects of the mid-bass and bass drivers tend to rock the speaker back and forth microscopically on a less than stable flooring surface thus having the effect of nulling, smearing or adding to the tweeter output.PROPERLY ADJUSTED spiking ensures a very stable reference platform from which the drivers can operate most accurately, dynamically and efficiently.
In addition, there is a smaller but useful benefit of allowing some excess cabinet resonance energy to be transfered to the large mass sink of the floor rather than having to dissipate itself within the loudspeaker enclosure and its exterior baffles/walls.
The typical effects heard will be crisper and better defined attack and note shapings, punchier dynamics, improved focus and stage size,improved resolution of fine details, articulation & separation of instruments and a tauter & more tuneful bass.... however...
... some will hear the effects as having less "romance", warmth and "bloom" and sometimes will be observed as being harder and more revealing of problems elsewhere in the system.

Not only can you hear better sound characteristics when your speaker stands have spikes going directly to the floor as mentioned above, but many people also use three small points under the speaker that rests on the speaker stand for additional improvement.
While I personally agree with the reasoning and experience of the above posts, I would note that John Dunlavy (Dunlavy speakers) does not use spikes on his well regarded speakers. Why? He just says that they don't "measure" better with spikes. I just wanted to see the contrary opinion noted, and no, I don't own Dunlavy speakers. Cheers. Craig
I used to have my floorstanding speakers spiked (through a low pile berber carpet) to a hardwood floor but experimented a few months ago with 1/4 inch laminated (security) glass-two 15" x 15" pieces, one beneath each speaker, no spikes. Total cost for the glass-about $35. My speakers are a little unusual in that they are a 3 way design with the woofer mounted internally firing straight up with the low frequency info exiting a round port below the tweeter (midrange driver above the tweeter). I can't say if this configuration has anything to do with the sound spiked versus on the laminated glass, but the glass was a major, and I mean major, improvement and has stayed. All the detail remained, but the presentation became much fuller and more fleshed out-it simply sounded more relaxed and much more like live music. The sound with spikes in places was much more fatiguing and shrill. With the speakers I have, I won't be using spikes again.