How they differ

Super Audio CDs and DVD audio discs may look the same as today's CDs, but the similarity ends there.

Both SACD and DVD Audio store about 4.7 gigabytes of data - more than seven times as much as conventional music CDs - by packing in more digital ones and zeros and using a higher frequency laser to read them.

Super Audio CD and DVD audio use that extra capacity to produce a richer sound than CDs. The formats cram more data onto their respective discs and extract it at higher "sampling rates" - the frequency with which the player refers to that data in presenting it to listeners as sound.

Despite their outward similarity, the discs themselves aren't interchangeable. SACD and DVD discs will not play in each other's machines. SACDs will play in standard CD players, but DVDs will not.

DVD-audio discs will play in DVD-video players, however.

Philips and Pioneer both plan to offer universal players that will play CDs, SACDs, and video and audio DVDs within a year.

(c) Copyright 1999. The Christian Science Publishing Society