I like what I started in my HT room and can't seem to stop this addiction. I have dual SVS 25-31's powered by a Sampson1000. I put the port plug in to lower the freq to 20. I know anything below this is felt so I think the shakers are a cheap way to get those lower effects. Also late night movie watching will still add that shake without the volume(great for horror flicks). I've been researching the buttkicker 2 with a 1000watt amp(can't remember the name) combo for around 700. The thing is can cheaper(but plentiful) Ebay shakers that go for around 50 sound just as good? I remember reading that the Butt2 can go down to 5hz. I hope my girlfriend won't have a new best friend...the couch.