SSM2005

–11–

REV. 0

TYPICAL OUTPUTS IN VARIOUS MODES

The SSM2005 Circle Surround decoder uses ambiance and

directional information already present in a stereo signal, and

does not require the audio signal to be encoded. The device

requires no delay generators or noise reduction. Fully differenti-

ated rear channels provide rear stereo separation for enhanced

spatial perception, a feature unique to Circle Surround.

Video mode provides the highest degree of channel separation

between the front and center speakers. Video mode cancels com-

mon center channel material from the left and right front chan-

nels. This restores a wide stereo image to matrix encoded sound

tracks, while maintaining a solid center channel for dialogue and

mono information.

The Music mode is optimized for unencoded stereo music repro-

duction, with full bandwidth on all channels. The steering for the

LF and RF channels is deactivated to prevent any stereo image

wandering. The independent two-band rear channel steering

provides excellent surround imaging, even in car audio applica-

tions. Well balanced sound is obtained everywhere within a 4- or

5-speaker setup.

The 5.2.5 mode provides the maximum channel separation to

the surround channels, and should be used with any encoded

stereo input signal. The 4.2.4 mode can be used to reduce the

dynamic steering of the surround channels, allowing the

SSM2005 to simulate a 4-channel surround sound decoder.

Sound Spread OFF allows the maximum channel separation

between the surround and front speakers. With Sound Spread

OFF, a hard panned left input signal will produce an output

only in the left front output. In Sound Spread ON mode, a hard

panned left input signal will produce equal output from the left

front and left surround outputs.

The following tables demonstrate the differences between the

differences in magnitude (in dB) and phase (in degrees). For

example, a 0

180

° input means L

Table V. Video/5.2.5/Sound Spread OFF/Center ON

Input

Output

(dB)

dB

φ

|LF|

|RF|

|C|

|LS|

|RS|

0

0

°

– 30

–30

+6

–40

–40

0

180

°

–35

–35

–45

+6

+6

0

–60

–30

–30

–35

–60

0

–30

–35

–30

–6

0

°

0

–15

–4

–25

–30

–6

180

°

–30

–36

–26

0

–15

Table VI. Video/5.2.5/Sound Spread ON/Center ON

Input

Output

(dB)

dB

φ

|LF|

|RF|

|C|

|LS|

|RS|

0

0

°

– 30

–30

+6

–40

–40

0

180

°

–35

–35

–45

+6

+6

0

–60

–30

0

–30

–60

0

–30

–30

0

–6

0

°

0

–15

–4

0

–25

–6

180

°

–30

–36

–26

0

–15

Table VII. Music/5.2.5/Sound Spread ON/Center ON

Input

Output

(dB)

dB

φ

|LF|

|RF|

|C|

|LS|

|RS|

0

0

°

0

0

+2

–40

–40

0

180

°

0

0

–45

+6

+6

0

–60

–30

0

–30

–60

0

–30

–30

0

–6

0

°

0

–6–40

–25

–6

180

°

0

–6

–26

0

–15

Table VIII. Video/5.2.5/Sound Spread ON/Phantom Center

Input

Output

(dB)

dB

φ

|LF|

|RF|

|C|

|LS|

|RS|

0

0

°

+3

+3

Off

–40

–40

0

180

°

–35

–35

Off

+6

+6

0

–60

Off

0

–30

–60

0

Off

–30

0

–6

0

°

0

–15

Off

0

–25

–6

180

°

–30

–36

Off

0

–15

Table IX. Video/4.2.4/Sound Spread OFF/Center ON

Input

Output

(dB)

dB

φ

|LF|

|RF|

|C|

|LS|

|RS|

0

0

°

– 30

–30

+6

–40

–40

0

180

°

–35

–35

–45

+6

+6

0

–60

–30

–32

–32

–60

0

–30

–32

–32

–6

0

°

0

–15

–4

–26

–26

–6

180

°

–30

–36

–26

0

–2