PowerPort venting technology belts out the kind of rich powerful bass you'd expect from much larger stereo speakers. Bass ports redirect the sound created by the back of the speaker cone into the room. But conventional bass ports lose efficiency and create distortion because of air turbulence at the mouth of the port.

PowerPort vastly reduces air turbulence at the port mouth thereby reducing distortion and increasing bass output. This is the same technology used in Polk's legendary $10,000 Signature Reference Theater system. In the I-Sonic ES and I-Sonic ES2 PowerPort delivers sound that is rich and warm, making all of your music and movies sound life-like and satisfying.

In the words of one reviewer: "The sound quality of the I-Sonic is extraordinary, but since it is from Polk, this isn't surprising. The cabinet has Polk's Power Port technology for hard-hitting and accurate bass..."