Polk Audio T30 Center Channel Speaker (Black) Every T-series speaker features premium acoustics, quality construction, easy setup and great value. The T-series high efficiency design is compatible with most home theater AV receivers 1 inch silk dome dynamic balance wave guide tweeter for transparent, crystal clear treble 2 x 5.25 inches extended throw composite dynamic balance drivers for open, uncoloured midrange and punchy, dynamic bass performance-tuned rear firing bass port delivers increased bass output.