Isolating Transmission Line speakers from floor

It is possible that spikes reduce energy transfer (extremely small contact point) but more likely they allow better coupling (especially on the carpet) to the floor.  As long as floor has lower resonance point than 20Hz it will reduce speaker vibration (added mass).  I use spikes, but in apartment building I would definitely use vibrapods.

My Transmission Line's sit directly on the floor, they dont accept or have spikes. 
Cheers Andrew

Spikes will definitely increase coupling. Townshends or feet like Isoacoustics Gaia will decouple.

I use Isoacoustics Gaia feet with mine and swear by them.

I used Gaia's on a set of Tannoy XT8F's, great result. Even the "Minister of Finance" was impressed... 

Well then you will love Podiums, a couple guys had Gaia and said the Podiums are a lot better. (Should be for the money! lol!)