[2gumby2]

I've seen subwoofer isolation devices similar to the one in the link below and was wondering about the merits of such devices. My subwoofers are using the typical spikes, but I'm curious about what advantages the subwoofer isolation devices would have compared to standard spikes.

http://blog.edesignaudio.com/?p=1062

[ctviggen]

I've used an ASC subtrap, which is similar to that.  I think the benefits are they lift the sub and also reduce vibrations.  The subtrap also acts as a trap, although how well it does this is up to debate. 

However, I never compared the subs with and without the traps, so I can't tell what exact benefit they are.

[DTB300]

Looks just like the Auralex Sub-Dude or Great Gramma.

[mcgsxr]

Not sure about that specific device, but I have been using sponge rubber hockey pucks (the soft practice ones) under my HT sub for years.  Like the effects, and love the $6 investment!

[Nuance]

I am using an Auralex Gramma and love it.  The bass tightens up a bit and seems to be a little more encompassing.  I think it has to do with raising the ground plane of the subs.  Whatever it is, it even measures differently, so I am a happy camper.