The use of separate transistors, resistors, etc. instead of integrated circuits in audio components. This is a more costly method, but these individual components usually have closer specifications, can dissipate heat more easily, and usually do a better job of reproducing the music. The original noise reduction process introduced by Dolby Laboratories is a complementary combination of encoding and decoding. During playback the volume of these passages is decreased by exactly the same amount. Since tape hiss is simply high frequency noise, it too is attenuated by the same measure with a net result of 10dB decrease in hiss.
Loud passages are completely unaffected by both the encoding and decoding processes.
Pro Logic creates a very realistic sound field-much like that experienced by those actually on the recording sound stage. The front center channel contains vocals and center sound effects. The vocals and sound effects are therefore reproduced exactly where they should be - the very center of the sound field above or below the receiver. The rear speakers help to recreate the reflective ambience of the original room in which the audio was recorded. They generate short echoes and delays that help make the entire audio experience more lifelike.