SVS Subwoofer Isolation feet. Will I lose bass?

To expound on the YT vid I mentioned, his measurements, if I remember correctly, showed almost no impact on a PORTED sub.  There certainly is a difference in the way cabinets react to a moving woofer in a sealed cabinet with no air escape, so this seems to make sense.

If these feet are detrimental to a sealed sub, I wonder why i have not heard anyone mention it.  

Could it be because we're all sheep and agree with our favorite poster or reviewer?

I know that MANY people have sealed subs and have sought after isolation.

@dtximages  I was actually considered getting these for my subwoofers, not realizing that there were already feet on them..  I was just checking out the SVS website and if I understand their pricing correctly it looks like it only cost $49+shipping for a set of four.  And there is a 45 day return period if not happy.  Seems reasonable enough, especially compared to some other audio items.

Yep @mahgister, the video you provided a link to (I really gotta learn how to do that ;-) is the one to which I was above referring.

I don't believe that demonstrating the reduction of acceleration of a speaker enclosure proves that it will improve the sound.  
First we have no indication of the amplitude of the vibration and acceleration.  It could be inconsequential. 
Second we have no evidence to suggest that the amplitude of the acceleration is audible.  The enclosure may already be sufficiently damped and braced as to make the vibration inaudible.  
Third is that the reduction of audible enclosure panel acceleation (if any) may make the sound quality less pleasing overall, especially if the manufacturer has tuned the resonance to augment the overall frequency response of the speaker.  Reducing that may make the speaker sound thin and less balanced.  
There is a lot more to this than showing a display of zero acceleration.  

I added the SVS isolation feet to my sealed SVS SB4000 subs a few months ago. I did not experience any noticeable change in output.
The reduced db output in the video has nothing to do with the feet or the flooring, it is because the ports are being plugged. Plugging the ports on a ported sub will change the tuning of the cabinet and thusly its output.