Instruct: Classify an Amazon review as either positive or negative.
Query: ample sub

Having owned speakers with 15" woofers for many decades I never could justify adding a subwoofer. However, my new receiver doesn't provide the low notes to the front main speakers as previously owned receivers. I could tell the bass was insufficient so I purchased this 12" Polk Audio sub with beautiful cherry veneer. The difference has shown a new dimension to music and movies that has been missing. This sub is easy to hook up and has serious thump. While I could shake the house before now the house absolutely throbs. Controls on the back can contour the sound to keep it from being overpowering. I'm now considering replacing my front main and center speakers with Polk.