Although this site is called AudiophileReview, we don't plan to regularly publish gear reviews, traditional gear reviews anyway. Our sister site HomeTheaterReview.com does a fine job of handling that. But occasionally something comes along that is too cool not to blather about. So here goes...
The number one complaint that I hear repeatedly about subwoofers is, "they hum." Occasionally an off-brand sub will hum because it has a badly designed amplifier, but most subwoofers from established companies do not hum when they are merely plugged into a wall socket and turned on. It's when you connect the cables from your receiver, preamp, or pre/pro to your subwoofer that problems begin - that pesky 60 or 120 Hz continuous low-level noise. Congratulations, you have a ground loop hum.
Sometimes you can reduce or eliminate a ground loop hum by moving your AC connections so all your devices are on the same AC circuit. But in many systems this isn't practical or even possible. A second oft-used solution is "floating" by disconnecting or removing the ground pin on the AC cable powering the subwoofer. But sometimes even floating a subwoofer's ground won't eliminate a ground loop hum. What do you do then?
If your subwoofer was hum-free before a line-level interconnect is attached to it, the Outlaw Audio OAW3 Wireless Audio System is the best solution I've found for eliminating hum. I know it worked for me.
I put an OAW3 in my own large-room home theater system to remove a low-level ground loop hum from an Earthquake Supernova MK VI 15 inch subwoofer. Installation was simple - I just pretended that the OAW3 was an interconnect cable. Merely plug the "sender" box's input into the line-level subwoofer output on your receiver or pre-pro and then plug the "receiver" box's RCA output into your subwoofer's input connector. Plug in AC for the OAW3 and push a button on the sender and one on the receiver, let them "handshake," and you're all done; set-up is completed.
The Outlaw OAW3 proved to be a better solution for my subwoofer hum problems than the similarly priced Aperion Audio Home Link wireless system which I reviewed for The Absolute Sound. On paper, the OAW3 boasts 2 dB better S/N ratio, but in real world I noticed that the OAW3 was substantially quieter than the Home Link. The OAW3 was almost dead silent, while the Home Link produced a low-level swooshing sound no matter where or how I installed it.
Obviously, if I had heard the OAW3 before I heard the Home Link, I would not have been as impressed by the Home Link. So, if your goal is to have the quietest subwoofers (except for when they must go boom), the Outlaw OAW3 should be at the top of your shopping list.