Speakers for expanding (enhancing) the audio system

Expansion of the AS

— add-on speaker modules that augment an existing system to get a wider frequency range, higher sound pressure, and a proper soundstage for movies/music. Most often these are height modules for Dolby Atmos. They add a vertical dimension to the soundstage and unlock Dolby Atmos/DTS:X tracks. These modules can be on-wall or in-ceiling, or reflective (up-firing) units that sit on the fronts and fire at the ceiling. For a seamless sound, choose modules from the same tonal family as the fronts, properly set levels, delays, and crossovers in the AVR, and run calibration via Audyssey/YPAO/Dirac. As a result, a familiar 5.1 turns into 5.1.2/5.1.4: helicopter flyovers pass overhead, rain comes from above, concert recordings gain a soaring hall dome, and in games you get a precise sense of height and direction—even at moderate volume.