In short, the larger the subwoofer, the louder it is. 10 to 12-inch subwoofers deliver the right balance of treble and bass, with suited for repetitive and non-repetitive beats with much more noticeable bass than 6 to 8-inch units. 15 and 18-inch subwoofers are more capable of deeper notes with a much rawer and higher output. You should also factor in the optimal listening position. A larger subwoofer tucked away in your living room corner could beat a smaller subwoofer sitting in your cabinet.