The ES90 is a pair of height (topper) speakers designed to add overhead effects to a Dolby Atmos or DTS:X home theater. Each module is angled upward so that its full-range driver reflects sound from the ceiling. It is intended to sit on the Signature Elite ES20, ES55 and ES60 and the Signature S20, S55 and S60 speakers. It is not compatible with the ES50, S50, ES15 or S15.

Each module combines a 5.25 in. mica-reinforced polypropylene midrange/midbass driver with a 1 in. Terylene dome tweeter, with a crossover at 2200 Hz. The woofer has about 75 percent more surface area than a traditional 4 in. height driver. A molded rubber base isolates the module from the speaker below to prevent rattles and buzzes, and an acoustically inert anti-diffraction grille covers the drivers.

Connection is by one pair of 5-way gold binding posts on each module, wired to the speaker outputs of a Dolby Atmos or DTS:X-compatible receiver. Nominal impedance is 4 ohms (8 ohm compatible), and the recommended amplifier power is 20–150 W per channel.