Acoustic Resonance Control (ARC)®
Acoustic Resonance Control (ARC) Port Technology
Sound emanating from the back of the driver creates an "organ pipe" resonance at a
frequency that is a function of the depth of the cabinet. This internal cabinet resonance can
impart a "thick" character to voices. Polk's patented* Acoustic Resonance Control (ARC)® port
system overcomes this problem. In addition to the bass port (usually a PowerPort) many Polk
models have a second small port (yellow tube in illustration) that is tuned to suppress the
internal cabinet resonance. ARC Port is found in RTi and LSi series. Thanks to patented ARC technology, you'll enjoy utterly clear and
natural midrange.
*US Patent # 5696357
