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Digital Performer: Pitch Craft

MOTU Digital Performer Tips & Techniques
Published April 2018
By Jim Cooper

Screen 1: Preparing a track for pitch-correction and editing. In Relative pitch mode (shown here), the single bar and the pitch line within it represent the current pitch of the vocals. Draw upwards with the Pencil tool to raise the pitch and downwards to lower it.Screen 1: Preparing a track for pitch-correction and editing. In Relative pitch mode (shown here), the single bar and the pitch line within it represent the current pitch of the vocals. Draw upwards with the Pencil tool to raise the pitch and downwards to lower it.

We explore DP’s tools for applying pitch-correction, harmony generation, pitch-quantising and pitch effects to vocal tracks.

Back in SOS February 2018, we looked at how to employ Digital Performer’s built-in comping functionality to combine the highlights of multiple takes into an edited vocal track. Hopefully, this comped vocal track will feature reasonably good pitch accuracy and inflection, but there is often scope for improvement!

To make minor pitch-corrections or adjustments (as seen in Screen 1 above), expand the height of the track in the Sequence Editor (1), zoom in the pitch ruler for finer resolution (2), choose Relative (versus Absolute) from the pitch layer mode menu (3), choose PureDSP Solo Vocal from the pitch-shift mode menu (4), and make your pitch edits with the Pencil tool (5).

In Relative pitch-editing mode (1), the single bar and the pitch line within it represent the current pitch of the vocals. The Pencil tool can be used to reshape the pitch line, drawing upwards to raise the pitch and downwards to lower it. To delete any adjustments, select with the I-beam and hit the Delete key. Additional basic pitch curve editing techniques, such as working with control points and parabolas, are described in the section beginning on page 880 in the Digital Performer User Guide, available from the Help menu. All of this can be done in real time, with the section looping.

Screen 2: In Absolute pitch mode, each segment represents a sung note. The thin line represents actual detected pitch. Grey bars represent unpitched material, such as sibilants and breaths. You can see the pitch edit made in screen 1 as the red portion of the line.Screen 2: In Absolute pitch mode, each segment represents a sung note. The thin line represents actual detected pitch. Grey bars represent unpitched material, such as sibilants and breaths. You can see the pitch edit made in screen 1 as the red portion of the line.

Screen 2 shows Absolute pitch mode (1), which is useful for more substantial pitch changes, such as changing the actual notes sung or creating harmonies from a solo vocal. The pitch ruler will change to an absolute pitch scale (2) with customary numbered octaves, and the notes of the audio detected by DP’s PureDSP or ZTX PRO pitch engine (3) will be represented as bar segments (4) aligned with the pitch ruler, which serve as a convenient mechanism for you to manipulate the source as discrete notes. The specific pitch at every point is represented by the thin blue line running horizontally through the segments.

In the screenshots, you can see a minor pitch edit made in Screen 1 as the red portion (5) of the line in Screen 2. Sections of unpitched audio such as breaths, sibilants, and so on appear as grey bars (6). You can freely switch between Absolute and Relative pitch modes: doing so has no effect whatsoever on the actual pitch of the audio, and the techniques for adjusting pitch segmentation discussed below apply to both.

Segmentation For The Nation

Before you begin dragging pitch segments to transpose or harmonise notes and phrases, it’s a good idea to make sure they accurately represent the actual notes in the material, and to correct this representation if necessary. Select the entire track, making sure that all audio in the track is selected, and choose Pitch Automation / Set Track Pitch Mode / Vocals (instead of Instrument) from the Audio menu to fine-tune the segments for vocal material. Check segment accuracy by playing through the track while watching the playback wiper pass over the pitch segments. If you need more coarse or fine detail overall, choose Audio Pitch Correction / Adjust Pitch Segmentation from the Audio menu and drag the slider accordingly.

To join two segments where there should only be one, click their border with the Mute (X) tool; to split a segment where there should be a division between notes, click with the Scissors tool. Segment boundaries can be adjusted by dragging them horizontally with the arrow cursor, which appears as a dual arrow when hovering over the boundary, and the length of a pitch segment can be changed by dragging either edge with the arrow cursor. None of these adjustments has any effect on the audio, just how accurately pitch is represented by the segments.

To change a note chromatically, drag it up or down by the number of desired half steps. It will snap chromatically to the pitch ruler, maintaining any slight offset it may have had originally from its root pitch. For microtonal adjustments, Command/Ctrl-drag to override ruler snapping. Zoom in vertically for more pitch resolution. To transpose several pitch segments, select them with the lasso (arrow tool) and drag any selected segment. To select all pitch segments, use the View Filter to hide soundbites and then Select All in the track. To revert to the original pitch, select the segments and choose Pitch Automation / Clear Pitch from the Audio menu.

Digital Performer also lets you ‘quantise’ pitch, which can be useful for clamping down hard on a sloppy vocal performance, or for creating the T‑Pain effect. Choose Pitch Automation / Quantize Pitch from the Audio menu and watch the selected segments magically snap to their respective root pitch (represented by the shaded rows behind them). Depending on the material, the situation and/or your creative goals, this can be a huge time-saver.

To take the T‑Pain effect to the extreme, use the Scissors tool to split long pitch segments as desired. If you want to conform pitch changes to beat subdivisions, turn on the edit grid beforehand and set it to eighth notes, 16th notes, or whatever is appropriate. The Scissors tool splits will then align with the beat grid. You can then drag all those resulting pitch segments to T‑Pain glory. Similarly, if you want to apply the classic ‘sampler’ effect to a soundbite when transposing it, rather than the more natural-sounding formant-corrected shifting we’ve been using so far, choose ZTX Standard from the pitch-shift mode menu. To A/B-compare your pitch edits with the original vocals, click the Pitch Layer Bypass ‘P’ button to temporarily disable your pitch edits.

Ahead Of The Curve

After making pitch segment edits, you’ll often find that you need to do some shaping of the pitch curve at segment transitions to keep it sounding natural. This is done with the Pencil tool and your ears.

The beauty of the pitch curve is that it represents all the subtle nuances of the singer’s performance. You can scale the curve to enhance desired nuances or remove unwanted ones. To do this for a single note, Option/Alt-click the curve anywhere on the note segment and then drag vertically up or down to scale the curve’s current shape, enhancing or reducing pitch variation respectively. To do this across multiple pitch segments, first select any portion of the curve you wish to modify with the I-beam tool. Scaling the pitch curve is a great way to enhance or reduce the amount of vibrato on a sustained note.

Sweet Harmony

To harmonise individual syllables, words, phrases or even a whole chorus, first duplicate the vocal track. This next step is very important: select the soundbites in the duplicate track and choose Merge Soundbites from the Audio menu. If you skip this step, any changes you make to the duplicate track will also affect the original track. Merging creates a whole new soundbite with its own pitch layer to edit independently.

Screen 3: With the pitch segments from Screen 1 cleaned up, the original vocal track (top) has been tweaked and then harmonised in the second track. Notice the first note is transposed up a fifth from F3 to D4, and adjusted closer to the correct note to make the interval sound more in tune.Screen 3: With the pitch segments from Screen 1 cleaned up, the original vocal track (top) has been tweaked and then harmonised in the second track. Notice the first note is transposed up a fifth from F3 to D4, and adjusted closer to the correct note to make the interval sound more in tune.

After merging, you may need to replicate some of the pitch edits you made in the original track, including pitch segment clean-up. Also, be sure the newly merged soundbite is set to PureDSP Solo Vocal mode. Now you can freely drag pitch segments up or down to harmonise as desired throughout the track. After snapping them to the desired chromatic pitch, try dragging slightly with the Command (Mac) or Ctrl (Windows) key to vary the pitch slightly for a more natural sound. You can also try nudging the soundbite(s) in the harmony track forward or backward in time with the arrow keys to mix up the timing a bit. If you want to build three- or four-part harmonies, repeat this procedure, duplicating a separate track for each layer. You will be surprised at how good it sounds, especially after applying reverb and other vocal channel effects.

You can also use the Transpose command from the Region menu to transpose the vocals, change modes (from major to minor, for example), and even completely transform them with custom transposition maps of your own making (Screen 3). This can be a huge time-saver for generating harmonies, as you can constrain transposition to certain notes in the scale while leaving others unaltered. The Transpose command can also be used to transpose vocals along with instrument tracks or other MIDI material in your project.

Mixed Doubles

Pitch segments in a vocal track can also be converted to MIDI notes, allowing them to be doubled on a virtual instrument. The accuracy of the conversion depends on how accurately the pitch segments represent the vocals. For best results, try quantising the pitch, as discussed earlier — perhaps on a duplicate vocal track, to preserve your nuanced edits — and make sure there is a direct correspondence between each pitch segment and the sung note it represents. Also, adjust the timing and duration of the pitch segments to accurately reflect their corresponding note. After making these preparations, select the segments with the arrow (lasso) cursor, copy, leave them selected, choose Set to Selection Bounds in the Selection Info panel Set To menu, click the name of the MIDI track to paste into, and paste. This ensures that the pasted MIDI notes line up with the pitch segments in the vocal track. To further refine the timing of the MIDI notes, try quantising both Note On and Note Off messages.  

Published April 2018