Trim Pass

Adapting a Mix for Different Environments

A feature film’s primary audio mix is typically created in a large, acoustically optimized theatrical environment, often for an immersive format like Dolby Atmos or 7.1 surround sound. This theatrical mix is designed to be played back loudly on a powerful, calibrated sound system. However, the vast majority of people will eventually watch the film at home on a variety of different systems: a 5.1 home theater setup, a television’s built-in speakers, a soundbar, or even headphones. The powerful theatrical mix will not translate correctly to these smaller, ‘near-field’ listening environments without adjustments.

A trim pass is the process of creating these alternate versions, or ‘printmasters.’ Instead of painstakingly remixing the entire film from scratch for each format—a prohibitively expensive and time-consuming task—the re-recording mixer performs a more streamlined pass. They work from the completed theatrical mix and make broad, overall adjustments to the main audio food groups (stems) like Dialogue, Music, and Effects (DME).

Common Trim Pass Workflows

Creating different versions of the mix requires addressing the unique characteristics of each playback format.

• Theatrical to Home Theater (5.1/7.1): The main goal here is often managing dynamic range. The huge dynamic swings of a theatrical mix can be overwhelming in a small living room. The mixer will typically perform a trim pass to slightly reduce the overall dynamic range. They might also adjust the level of the surround channels, as the speakers are much closer to the listener at home. The LFE (subwoofer) channel is also often trimmed down to avoid overpowering a domestic setup.
• Surround to Stereo (2.0): This is one of the most critical trim passes. The mixer must intelligently ‘fold down’ all the information from the center and surround speakers into just the left and right channels. This is not a simple automated process. Care must be taken to ensure the dialogue, which lives primarily in the center channel, remains clear and anchored in the center of the stereo image. The ambience and effects from the surround channels must be carefully balanced and panned into the stereo field to create a sense of space without cluttering the mix.
• M&E (Music & Effects): A special trim pass is done to create the ‘M&E’ track, which is the full film mix with the dialogue stem completely muted. This version is sent to international distributors, who then use it to dub the dialogue in their local language.

Modern Digital Audio Workstations (DAWs) facilitate this process by allowing mixers to ‘gang’ all the tracks within a stem, so a single fader move can trim the overall level of all effects or all music tracks simultaneously, preserving the detailed automation within the original mix.