How to Mix Sound for Different Speaker Setups

This patent describes a system for mixing and playing back audio, allowing sound engineers to precisely control where sounds appear in a room, even preventing sounds from playing through specific speakers.

What it covers

This patent covers a system that takes many separate audio tracks, called monophonic audio streams, and mixes them together. Some tracks are 'object-based,' meaning they have specific 3D locations in a virtual space, like a car driving across the screen. Other tracks are 'channel-based,' which are assigned to specific speakers, like the front left or right. The system uses metadata, which is like extra information, to tell a playback device exactly where each sound should come from. Crucially, for object-based sounds, this metadata can also specify if a sound is *not* allowed to play through certain speakers. This lets sound designers ensure a specific effect, like a whisper, doesn't blast from a rear speaker, maintaining the intended immersive experience for the listener in any room setup.

What it doesn't cover

• —Audio systems that only use channel-based audio without any object-based audio elements.
• —Audio systems that do not use metadata to define playback locations for audio streams.
• —Audio systems that do not allow for prohibiting specific speaker outputs for object-based audio.
• —Audio systems that do not combine multiple monophonic audio streams into a single bitstream.
• —Audio systems that only support 2D spatial audio rather than 3D.

The clever bit

The key innovation is the ability to prohibit specific speaker outputs for object-based audio. This provides granular control beyond simply placing sounds, allowing sound designers to avoid unwanted audio bleed or ensure certain effects are localized precisely, even when the playback system has many speakers.

Why it matters

Dolby is a major player in audio technology, and this patent is part of their ongoing work to advance immersive sound experiences. Technologies like this are fundamental to modern surround sound and spatial audio formats used in movies, gaming, and music, ensuring consistent and high-quality audio across diverse playback environments.

Real-world examples

• 1.Dolby Atmos
• 2.Modern home theater systems
• 3.Immersive gaming audio engines
• 4.Advanced movie soundtrack mixing