These fantastic Polk RT-600 speakers are incredibly well constructed. Polk used 0.75" medium density fiberboard (MDF) with the exception of the front panel, which is constructed from 1" MDF. This front panel has rounded edges and its room facing surface is covered with a velvet-like material (trade name, Velvin). The 1" thickness, rounded edges, and Velvin coating are obviously intended to reduce resonances, diffraction, and reflection.

The two drivers (1" tri-laminate tweeter and 6.5" mid/sub) are mounted 1" apart and 0.5" out from the front baffle. The drivers are mounted in an egg-shaped plate or bezel, approximately 0.5" deep, 11" H, and 7" W. This plate is made out of a acoustically inert mixture of mineral and glass compound and weighs in at almost 3 pounds. This bezel minimizes resonances and its 0.5" protrusion from the front panel makes for a seamless interface (no sharp edges) between it and the molded anti-diffraction grille.

There are two ports associated with the 600. The conventional bass port (about 3" in diameter) is located on the bottom of the enclosure with approximately 1.5" of clearance between the port and the base plate. This port utilizes Polk's Power Port technology, which minimizes turbulence, noise, and loss at the bass frequencies.

A smaller port (approximately 1" in diameter) is located at the bottom of the egg-shaped bezel. This port is tuned to the cabinet's front panel to back panel resonance but 180 degrees out of phase with this resonance. The resultant peak of the cabinet's front to back resonance is thereby minimized, resulting in cleaner sound, particularly with vocals. Polk calls this "Acoustic Resonance Control" (ARC) and claims it results in not only cleaner vocals but also in better image depth and superior localization stability.

The speakers measure 97.47cm high, 20.32cm wide, and 26.67cm deep . As a result, the RT600i occupies very little floor space and is quite easy to accommodate in most rooms.

And of course they sound just stunning!