SSA Menu

This menu page is used to configure the SSA instrument (Surround Sound Analyzer). The Surround Sound Analyzer (SSA) is a powerful tool for visualizing serveral aspects of surround signals in parallel, e. g. the balance between front and surround channels and between L-C-R channels, display of either phantom sound sources or correlators or both, total volume indication, dominant sound events, phase relationships and many others. The dynamic behaviour of all display elements (house display) corresponds to the subjective listening impression so that the balance of a surround programme can be intuitively monitored at a glance.

Detailed information about the display can be found in the  -> Background: SSA chapter at the end of this help page.

  

Initial Instrument Settings section
Key Settings section
Background: SSA
 
 

Initial Instrument Settings section  

  

• Scale
This key is used to select the scale for the 45° coordinate system. With Classic selected, the marking of the axes follows the settings of the PPM and SPL displays. In SPL based audio groups, Classic is the only available scale mode selection. With loudness based audio groups (e. g. r128, ITU and so on), the display scale set to Loudness will overtake the markings and settings of the selected loudness standard.

Options:

  

Classic | Loudness

Default value:

  

Classic

  

• PSI
This key is used to activate or deactivate the phantom source indicators showing the position and width of phantom sound sources. The line colors show the phase correlation of the adjacent channels (green: positive range, yellow: "0" range, red: negative range).

Options:

  

on | off

Default value:

  

on

  

• DMI
This key is used to activate or deactivate the indicator for the position of the dominant sound event (dominance vector - subjectivly sensed acoustical focal point).

Options:

  

on | off

Default value:

  

on

  

• Correlator
This key is used to activate or deactivate the additional phase correlation meters of the outer (surround) channel pair(s).

Options:

  

on | off

Default value:

  

on

  

• LFE Phase
This key is used to activate or deactivate the additional warning display "LFE Phase!". This warning lights up in the lower section of the SSA, if the correlation between any channel and the LFE channel turns to negativ values.

Options:

  

on | off

Default value:

  

off

  

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Key Settings section  

  

• Keys
The "SSA Keys" menu entered with the "Configure" key is used to define the keys that will be available in the instrument's and the local Control Bar and to define the routing of the global keyboard.

  

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Background: SSA  

The Surround Sound Analyzer display is based on the loudness like ITU BS.1770 (k) or other weighting filters. It equates to the listening sound pressure level, when the SurroundControl units and the studio monitoring system are properly calibrated. The axes of the 45° rotated coordinate system use dB SPL, LKFS, LU, or LUFS scales, with a reference mark that is also shown in the loudness and SPL displays in the Program Meter.
The polygon is generated by combining the displayed level values on the scales of the 45° coordinate system. When all channels are set to the same level with a white noise signal the result is a square, the area of which is a measure of the total sound volume. The distribution of the four quadrants shows the volume distribution in the surround system. In addition to this the display also takes into account the phase correlation and the position of possible phantom sound sources.

The critical center channel
The balance between the center channel and the L and R channels is a critical factor in all types of surround sound productions. We have thus allocated a separate pair of display bars to this parameter to show clearly the volume differences between the center and the L and R channels. Another indicator makes it possible to identify the base width of the center sound source, which can be useful when there is crosstalk into the L or R channels.

  

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