IsoAcoustic single sub unit.
I bought one of these for a ten inch Infinity subwoofer, and although it seems a bit small, it supports the big box very well, with no apparent imbalance. This is clearly a heavier duty model than the speaker/monitor versions, and I would have rated it higher, EXCEPT that I have wood floors, and the rubbery stuff used in IsoAcoustic devices seems to be sorbothane or something like it. Sorbothane is great for vibration control, but terrible for wood finishes, melting finishes or staining and therefore RUINING your fancy finished floors, table tops, shelves, etc. Therefore you have to put something between the feet of this device and wood. Had I known this included the unfortunate properties that it does, I would not have purchased it. I am using it now, but the sub with IsoAcoustic stand now resting upon an Auralex Sub-Dude, which is SAFE for finished wood flooring. If you're using it on carpet, or you place carpet under it, then you probably have nothing to worry about. Does it tighten Bass? I haven't found any evidence of that, but I don't turn the bass up so high as to rattle the walls. The important thing is that it decouples the bass from the floor, so it doesn't rattle and vibrate glass in cabinets. Decoupling was the point, but I suspect the Sub-Dude does that just as well, without the IsoAcoustic stand. FWIW, I also have the small and medium IsoAcoustic stands, and the smalls seem to work only reasonably well, while I'm not sure the mediums work well at all - the mediums seem stiff, inflexible, and though they do support my monitors well, the desk upon which they stand STILL vibrates. I expect I'll put Auralex beneath those. In other words, these are NOT the last word in decoupling or acoustic isolation, despite the advertising. Perhaps the weight range between small and medium affects the stands' performance, but I expected more for the money.