The ES15 is a passive two-way compact speaker in the Polk Signature Elite range. A 1-inch Terylene dome tweeter handles the highs, reaching 40 kHz and carrying Hi-Res Audio certification. A 5.25-inch mica-reinforced polypropylene driver covers the lows and mids. The pair is rated for 44 Hz to 40 kHz with a 2.3 kHz crossover point.

Bass output relies on the Power Port design, which has a larger surface area and smoother airflow than a conventional port, aiming for more output with less distortion. The cabinet is made of Medite MDF to reduce internal resonances. A magnetic, anti-diffraction grille is removable, and the front array uses phase-optimized crossovers.

Connection is through a single set of gold-plated five-way binding posts on each speaker. The speakers work with 8 ohm amplifier outputs and a recommended 20 to 100 watts per channel. A key-hole slot allows wall mounting, and the speakers can also sit on a shelf or stand. They are offered in black, white and brown.