Home Theater Audio: How to Choose the Perfect Setup
Posted 05/26/2011 at 1:39pm | by Michael Brown
The Same, But Smaller
Because studios often prefer to use some of Blu-ray’s storage capacity for non-audio-related features (e.g., making-of documentaries, coming attractions, alternate endings, and so on), many Blu-ray soundtracks are still compressed. Blu-ray soundtracks, however, are compressed with lossless codecs that don’t throw away any of the information contained in the original signal. The upshot is the soundtrack contains all the same information as the studio master, but requires much less storage.
So why doesn’t DVD use lossless algorithms? Simple: The computing power required for decoding was too expensive at the time DVD standards were established. Dolby TrueHD and DTS HD Master Audio are the two most common codecs you’ll encounter in Blu-ray discs, but they require too much bandwidth to be used in digital cable or satellite TV.
Regardless of which encoding scheme is used in your disc of choice, its bit stream must be decoded and decompressed to LPCM (linear pulse code modulation) before your amplifier can convert the data to an analog stream required by your speakers. This decoding and decompression can be done by your disc player or set-top box, or an A/V receiver can do the work. Regardless of how it’s done, once you have the equipment capable of reproducing these high-definition movie soundtracks in your living room, you’ll never want to set foot in another multiplex because movies will sound better at home.
Here’s a quick look at three classes of home-theater audio systems.