Tell us more about your system and room. What kind of floors are we talking here? That will be a consideration when considering spikes. If you are looking for tighter bass, you might want to look at your amp. Maybe an amp with a higher damping factor would help.
improving bass on large floorstanders....
I have some 3 way tower speakers that could use some bass improvement...however...if the results are minimal...i probably will pass...at any rate...would the addition of floor spikes or possibly a cable change be the answer?...I am looking for tighter, leaner bass if possible...thinking entry DH labs or Nordost...at any rates...what has worked/ not worked for others?