The Mackie SWA1501 is a subwoofer system that is designed for live sound reinforcement. It's a got an active 15" woofer and is of course to be used in within the context of a full PA system. The studio that I work at has a full PA rig as we sometimes do live shows in the studio and put on a festival every year. We've got two of these subwoofers in this system and while they only get used every now and again, the owner likes having it as it does indeed get used sometimes. Like me say that this sub can produce some extremely low and extremely loud low frequencies. It's definitely necessary to have a proper sub for live sound, and the SW1501 is just that. It's nice that this is an active sub woofer as it doesn't require an external power source and is fully functional on it's own. It's got a built in crossover section and XLR connections for it to plug everything into it. I don't remember off the top of my head what the other speakers are that we have with the SWA1501, but it's an all Mackie PA system and can get extremely loud for all frequencies and especially the low end part of things with the SWA1051. I don't really know what the Mackie SWA1501 will cost you, but as with any PA system sub woofer it's going to be at least a decent amount. Having said this, Mackie gear in general is some of the best bang for your buck and that's what you're going to get with the SWA1501 as well. It's probably not the most professional subwoofer, but unless you're a venue where you're using it every night, it's definitely adequate. I'd check out the full compliment of Mackie PA gear if you're looking to put one together for yourself as they have options for everyone.