Disc Reading
Objective lenses in conventional CD players have a longer working distance, or focal length, than lenses designed for SACD players. This means that when a hybrid SACD is placed into a conventional CD player, the laser beam passes the high-resolution layer and is reflected by the conventional layer at the standard 1.2 mm distance, and the high-density layer is out of focus. When the disc is placed into an SACD player, the laser is reflected by the high-resolution layer (at 600 µm distance) before it can reach the conventional layer. Conversely, if a conventional CD is placed into an SACD player, the laser will read the disc as a CD since there is no high-resolution layer.
Read more about this topic: Super Audio CD
Famous quotes containing the words disc and/or reading:
“Soundless as dots—on a Disc of Snow—”
—Emily Dickinson (1830–1886)
“How many a man has dated a new era in his life from the reading of a book.”
—Henry David Thoreau (1817–1862)