Matrix decoder

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Matrix decoder is an audio technology where a finite number of discrete audio channels (eg. 2) are decoded into a larger number of channels on play back (eg. 5). The channels are generally, but not always, arranged for decoding by an encoder, and decoded for playback by a decoder.

The notation for matrix encoding consists of the number of discrete audio channels separated by a colon from the number of decoded channels. For example, two discrete channels decoded to four-channels would be notated:

2:4

Five discrete channels decoded to six channels would be notated:

5:6

Many matrix encoders take advantage of the Haas effect, as well as audio cues inherent in the source channels.

The various encoding matrixes are described below.

Contents

[edit] SQ Matrix (2:4, "Surround Quadraphonic", "Stereo Quadraphonic", CBS SQ)

Encoding Matrix Left Front Right Front Left Back Right Back
Left Total 1.0 0.0 j0.7 k0.7
Right Total 0.0 1.0 k0.7 j0.7

j = + 90º phase-shift , k = - 90º phase-shift

[edit] QS Matrix (2:4, "Quadraphonic Stereo", QS)

Encoding Matrix Left Front Right Front Left Back Right Back
Left Total 0.92 0.38 j0.92 j0.38
Right Total 0.38 0.92 k0.38 k0.92

j = + 90º phase-shift , k = - 90º phase-shift

[edit] Ambisonics UHJ coding matrix (2:3)

Encoding Matrix W (pressure signal) X (front-back information) Y (left-right information)
Left Total 0.470 + k0.171 0.093 + j0.255 +0.328
Right Total 0.470 + j0.171 0.093 + k0.255 -0.328

j = + 90º phase-shift , k = - 90º phase-shift

[edit] Dolby Surround Surround Matrix (2:4)

Encoding Matrix Left Right Center Surround
Left Total 1.000 0.000 0.707 j0.707
Right Total 0.000 1.000 0.707 k0.707

j = + 90º phase-shift , k = - 90º phase-shift

[edit] Dolby Pro Logic Matrix (2:4)

The encoding matix is the same as for Dolby Surround; only the Pro Logic decoder differs.

Encoding Matrix Left Right Center Surround
Left Total 1.000 0.000 0.707 j0.707
Right Total 0.000 1.000 0.707 k0.707

j = + 90º phase-shift , k = - 90º phase-shift

[edit] Dolby Pro Logic II Matrix (2:5)

Encoding Matrix Left Right Center Rear Left Rear Right
Left Total 1.000 0.000 0.707 j0.8165 j0.5774
Right Total 0.000 1.000 0.707 k0.5774 k0.8165

j = + 90º phase-shift , k = - 90º phase-shift

[edit] See also


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