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Digital Performer: Exporting Audio Stems

MOTU Digital Performer: Tips & Techniques By Matt Lapoint
Published August 2023

Screen 1: DP’s Bounce to Disk window. In this example, aux buses have been set up in advance to produce stems with one click.Screen 1: DP’s Bounce to Disk window. In this example, aux buses have been set up in advance to produce stems with one click.

DP’s extensive Bounce options make exporting stems a breeze.

The audio production term ‘stem’ generally refers to a processed, self‑contained stereo mix of an instrument or family of combined similar instruments. For example, a stem could consist of a solo trumpet or an entire brass section. Stem breakouts are usually dictated by a project’s specific delivery requirements. In post‑production, greater flexibility is often required because musical elements are mixed with dialogue and sound effects. In song production, stems are a common delivery format that allows for variations across distribution and deployment scenarios, such as licensing and live playback. Some mastering engineers will request stems from the mix engineer to create a final master. In addition to processing, stems usually include all rendered edits, pitch and timing adjustments, as well as volume automation and processing. Stems can be dry, with separate reverb‑only stems being additionally created, or stems can be printed with all effects baked in. Through the use of bouncing tracks and outputs, Digital Performer 11 can bounce stems, tracks, buses and outputs, all from one window, all at the same time.

Templates

Bouncing is an essential and efficient way to finalise mixes and stems for delivery, especially for film and TV composers. Bouncing files for delivery has the potential to be a tedious and time‑consuming process if projects and templates aren’t set up correctly in advance. You should carefully decide what breakouts will be necessary for a given scoring project, and design and modify track routings before your writing process begins. When the time comes to send reference mixes, or final exports and stems, the routings and selections will be ready to go.

When designing a comprehensive DP template, it’s important to know what kind of tracks can be included in a Bounce to Disk operation. Individual audio tracks can be bounced separately, and will include all track insert effects, soundbite edits, and automation. This is also true for aux tracks and combined instrument tracks.

Digital Performer 11 can bounce stems, tracks, buses and outputs, all from one window, all at the same time.

Here’s an important tip: audio tracks and virtual instrument tracks can be assigned to stereo buses that feed aux tracks. Because aux tracks can be bounced as tracks, this is a way to combine audio tracks and virtual instrument tracks into stem groups.

When using reverb plug‑ins on different families of instruments, it’s important to create separate reverb plug‑in instances for each stem group. Otherwise, common‑use reverb returns could bleed into multiple stems from unwanted instruments using the same reverb. Separate reverbs, created using aux tracks, can be bused to their corresponding stem aux tracks so the audio and reverb are both sent to the same destination stem. Use the stem aux tracks for overall level control, EQ, compression and limiting as well, if necessary.

MIDI tracks assigned to multitimbral virtual instruments require separate bouncing for audio separation. Fortunately, most VIs have multiple outs that can be assigned to separate aux tracks.

Master fader effects are not included when bouncing tracks in the Bounce window. If master fader effects are an integral part of the signal processing, bouncing outputs will be necessary. Outputs can be both hardware outputs and DP internal buses. With buses, aux tracks are the best way to control the gain stage.

Making Selections

The bouncing features in Digital Performer are based on selecting MIDI and audio data in the timeline first. If data isn’t visibly selected, it won’t get bounced. Make sure track folders are open (expanded) to ensure all the track data gets selected. There are a few ways to make selections in DP. Click and drag a selection across single or multiple tracks, or use Select All inside various edit windows in DP. The Tracks window is quite useful when making bounce selections in DP (see Screen 2).

Screen 2: Use the Tracks window and Selection Info strip to choose what to bounce. You can even save and load selections for instant recall.Screen 2: Use the Tracks window and Selection Info strip to choose what to bounce. You can even save and load selections for instant recall.

At the top centre of the Tracks window is the Selection Information strip. Selection start/end times are displayed by bars/beats/ticks. The Time Formats window in DP’s Setup menu can change the time format, if desired. Using the menu to the right of the start and end times, selections can be based on Chunk Bounds, Remember Times, the counter position, and Saved Times. Markers are another useful way to create selection boundaries. First, Select All and then click the name of a marker in the timeline. Doing so highlights the data from that marker to the next marker in the timeline. Select all tracks you are ready to bounce. The Bounce window intelligently bases the track sources on the selection made before invoking the Bounce window.

Formats & Other Settings

Screen 3: The Bounce to Disk settings.Screen 3: The Bounce to Disk settings.After selecting a combination of tracks and outputs for bouncing, choose File / Bounce to Disk and then use the left column to choose file settings (Screen 3).

Bounced files can be uncompressed formats such as Broadcast Wave and AIFF (either interleaved or de‑interleaved), or compressed formats like MP3. The Project Format option is based on the file settings currently chosen in DP Preferences / Audio Files. Bouncing as a movie is also an option for both Mac and Windows platforms. Mode allows bouncing offline or in real time. The offline bounce speed varies based on the types of plug‑ins and virtual instruments that are being bounced. The Channels setting provides options for surround channels (if surround bundles are being used in the project), stereo, and mono (with and without attenuation). Sample Format provides options from 16‑bit up to 32‑bit floating‑point files. Import provides the option to import the bounced audio back into the project timeline. This option is only available for uncompressed formats. If this is set to Do Not Import, the default location of the files is the Bounces folder on the root level of every project folder.

At the bottom of the column, Choose Folder allows for a custom location for the bounced files. Overwrite Existing Files is an additional option at the bottom to preserve or write over files with the same names. Source can be tracks, outputs or both. File Name is for naming the file and adds the output and track name as an extension to the chosen name. There are three additional tick boxes at the bottom of this column. The first two will be further explained below. The third option, Save settings as Audio Export Format, saves all of the upper menu choices (File Format, Channels, Import, and so on) as a preset that can be recalled from the File Format menu. Saved Audio Export Formats are global and available in all other DP projects.

Bounce Again & Multi Bounce

Screen 4: The Bounce Again settings.Screen 4: The Bounce Again settings.Save Settings for Bounce Again (Screen 4) is a powerful feature that allows you to bounce the project again and retain all necessary settings, including selections, tracks, outputs and file format. Use the Settings Name field below to name and create a Bounce Again preset. A custom keyboard shortcut can be assigned to invoke this preset again.

Time‑saving tip: after selecting a track and time duration to save as a Bounce Again setting, run the bounce, but then cancel the process right after it gets started. You don’t have to wait for the bounce operation to be completed: all bounce settings are retained, even if you cancel. Select All Before Running Saved Bounce will perform a Select All command for the entire timeline boundary of a project (or active chunk) before bouncing.

Screen 5:  Bounce Settings.Screen 5: Bounce Settings.DP’s File menu contains a Bounce Settings sub‑menu with options to Run Last Bounce Again, Edit Bounce Again Settings, and Multi Bounce (see Screen 5). The Bounce Includes Audio Patch Thru menu option, when checked, leaves track inputs active during a real‑time bounce so that, for example, an external hardware synth could be included in a real‑time bounce if routed to a stereo track set to Audio Patch Thru. Saved Bounce Again settings appear in the Multi Bounce window and in the Bounce Settings menu (at the bottom of the menu).

The Multi Bounce window displays Bounce Again presets that were created in the currently loaded project. However, it also displays any presets that you have loaded (from other projects) while no project is open. So, if you have presets that you always want available, regardless of which DP project is currently open (or with no project open at all), then close all projects (keep DP running), open Multi Bounce and then click the Add button to load them from the desired DP project(s) on disk.

The Edit‑related menu options allow for deleting and renaming saved settings. The Multi Bounce window lists saved Bounce Again settings created in the current project (see Screen 6). Remove deletes selected settings. Add provides a file dialogue window where other project files can be searched for and selected.

Screen 6: Multi‑Bounce lets you create stems from multiple saved bounces, even across multiple DP projects, in one go.Screen 6: Multi‑Bounce lets you create stems from multiple saved bounces, even across multiple DP projects, in one go.Bounce Again settings are stored in project files and can be added to the Multi Bounce window. After selecting all or specific saved Bounce Again settings, hit OK and DP will perform the bounces.

Tip: the Multi Bounce can be accessed while DP is running but no project is currently loaded. Depending on the request, DP will open projects, make selections, and perform bounces, then close and move to the next bounce operation. A progress meter will appear giving feedback on the status of the Multi Bounce operation. Once completed, a report will pop up to list what was completed.

Bounce To This

Stem Bounce is a powerful and convenient method of exporting a combination of audio tracks, instrument tracks, aux tracks and outputs at the same time. Combined with Multi Bounce, Digital Performer provides the flexibility to quickly bounce stems, from the early stages of a project all the way to final delivery.