is a progressive volume-dependent loudness technology which avoids the loss of the effect impression during reducing volume. The Audyssey Dynamic EQ technology takes account of human perceptivity at differing volumes in addition to the room acoustics.

This means that voices are clear and distinct even at low volumes, the bass is full and the surround effects apply across the entire room. Dynamic EQ enables you to experience the original richness of sound at any volume.

You can find more information (in English) here.