What’s so special about Dolby Atmos?
In a normal surround sound mix, sound sources are positioned by using a surround panner to feed differing amounts of the source signal to each speaker in the monitoring system. When satisfied with the balance, the engineer will export the results to a set of discrete audio files, one for each channel of the targeted surround configuration. This effectively “burns in” the relative balance between each surround channel, and so, to accurately reproduce the intended surround sound field, a playback system should match exactly the speaker configuration and placement used during mixing. Even the mix studio’s room dimensions and properties would be duplicated for 100% accuracy.
In a Dolby Atmos system, however, sound sources are routed to any of up to 128 channels, or “objects”. These objects can be positioned and animated in three dimensions, with that positional information stored as metadata alongside the audio data. On playback, the Dolby Atmos decoder uses that positional data to calculate how to distribute each object’s signal among the playback system’s speakers, no matter how many speakers are being used. Configured correctly, it can also mitigate for differences in speaker positions and room dimensions.