Depending on how you look at it, subwoofers can radically increase or decrease the cost of a home theater system. A 5 channel system without a subwoofer can produce the same, or more, bass than a system with a subwoofer. Having 4 speakers each with a 15" woofer will produce a lot more bass than a single subwoofer. The problem is that these speakers would be very expensive and a very large multi-channel amplifier would be necessary to drive them. Having 4 smaller speakers with a smaller amp, and a powered sub would be a cheaper option. Of course, using 4 smaller speakers and no subwoofer is the cheapest option, but this system would not provide a lot of bass.