Multichannel and spatialization

In the context of multichannel examinations, the sound rendering is partly dependent on the spatialization.
Spatialization will depend on the distribution of sound levels and the effects applied to the sounds.
As much as it is difficult to measure the sound effects which will remain more in the notion of appreciation, the measurement of the distribution of the sound levels is easier to implement.
This measurement allows to define a comparison criterion.
This criterion takes into account the distribution between the front and surround channels (without top) and the front and top surround channels.

Spatialisation = Function (Peak Level front, Peak Level rear, Peak Level top, RMS Level front, RMS Level rear, RMS Level top)


This criterion is an indication of the spatial distribution of the sound, not of the quality of the spatial mixing of the sound.


This allows us to define a score from 0 to 5 for 5.1 or 7.1 formats :

Spatialization : ●●●●o (4)

And a score from 0 to 10 for the Atmos format (based on the 7.1.4) :

Spatialization : ●●●●●●●ooo (7)

With this notation, an Atmos track without sound in the top channels will have a maximum score of 5 like a track in 5.1 or 7.1.

In addition to this note, a graphical representation allows to better visualize this spatialization.
The graph represents the maximum and average level (RMS) of each channel in 5.1, 7.1 and 7.1.4 mode.
The blue circle indicates the maximum peak level for each channel, the larger the diameter, the higher the peak level.
The orange circle indicates the average level (RMS) for each channel, the larger the diameter, the higher the average level (RMS). Updated on 05/05/2022 to handle a 15 dB difference between front and surround levels. All ratings are updated accordingly.
Here are some examples of this new criterion.

Representation of the DTS HDMA 5.1 track of the audio bluray of the album The Tipping Point of Tears For Fears.

Spatialization : ●●●●o (4)

Representation of the DTS 5.1 track of the CD of the album On Air of Alan Parsons.

Spatialization : ●●●●● (4.8)

Representation of the Dolby True HD 7.1 track of the audio bluray of the album The Tipping Point of Tears For Fears.

Spatialization : ●●●●o (4.5)

Representation of the Dolby Atmos from Tidal of the album The Tipping Point of Tears For Fears.

Spatialization : ●●●●●●●●●o (9.2)

Representation of the Dolby Atmos from Tidal of the Taylor Swift’s song Fearless. The music style is mainly forward-focused, with the surrounds providing just a little space.

Spatialization : ●●●●oooooo (4.5)

Representation of the Dolby Atmos from Tidal of the song Shallow from Lady Gaga, Bradley Cooper.

Spatialization : ●●●●●●●●oo (7.7)

Representation of the Dolby Atmos from Tidal of the Coldplay’s song My universe.

Spatialization : ●●●●●●●ooo (7)

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