Digital Performer Help

Bit depth or resolution is the number of ones and zeros used to describe a digital audio sample. Commercial CDs use 16-bit samples. MOTU software has the ability to record 16 bit or 24 bit samples. Under some circumstances, it may be desirable to have lower sample resolution, such as 8 bit web audio or 12 bit sampler playback.

It is possible to change the bit depth of digital audio. Reducing the bit depth adds quantization distortion. To overcome this, dither can be applied. Dither is a small bit of noise that is applied the digital audio as it is quantized. This actually reduces the amount of distortion introduced by quantization, and has a more pleasing sound, particularly for softer passages in material with a wide dynamic range. The disadvantage of adding dither is an increased noise floor. Noise-shaping spectrally shapes the dither noise so that it is less apparent.

Digital Performer’s mixing and processing engine employs 32-bit resolution. When 16-bit or 24-bit digital audio first enters Digital Performer, its bit depth (resolution) is raised to 32-bits. From then on, as the audio is mixed and processed, it remains at 32 bits until it leaves Digital Performer. The Dither command, when checked, makes Digital Performer use dither whenever it must reduce the bit depth of audio. For example, if you bounce your mix to disk as a 16-bit, 44.1 kHz AIFF audio file to later burn a CD, Digital Performer converts your mix, which internally is being processed in 32 bits, to 16 bits during the bounce operation. If the Dither command is checked, dither is employed to help reduce the inherent quantization distortion that occurs when audio bit resolution is reduced.

Use Merge Soundbites to quickly create a single, new soundbite out of several adjacent soundbites. To do so, select the adjacent soundbites and choose Merge Soundbites from the Audio menu. This operation creates a new audio file, sort of like a "mini-bounce". But it does not include any volume, pan or other automation data. It is meant for joining audio regions on a small, local scale.

If you use the Merge Soundbites command when there is a time range selection that extends beyond the selected soundbite(s), the beginning of the resulting soundbite will extend to the beginning of the selection.

Strip Silence breaks up a soundbite into several smaller soundbites by removing all of the portions that consist of silence.

For example, you can use Strip Silence to remove the silence between words to separate them.

Threshold: The Threshold is a cut off point for the (amplitude) level of the audio. If audio falls below the threshold, it will be cut. If it rises above the threshold, it won’t be cut. The Threshold is expressed in percent of amplitude; values range from 1 to 100%. What value you should use depends on the nature of the audio and the signal to noise ratio. The rule of thumb is to try to set it as low as possible without generating unwanted soundbites (that are merely “noisy silence“) or extensions at either end of soundbites.

Attack: The Attack is the minimum amount of time in milliseconds that audio must remain above the Threshold in order not to be cut. If the audio contains percussive attacks, such as drum sounds, you can set this fairly low (less than 10 milliseconds) to obtain a clean attack on the resulting soundbites. If the audio contains longer, sloping attacks, or irregular attacks, you might need to set this higher to avoid a clipped effect at the beginning of the soundbite.

Release: The Release is the period of time in milliseconds in which the audio must remain below the threshold in order to be cut. If the audio stays below the threshold for as long as the duration, it will be cut. If it rises above the threshold before the duration has passed, it will not be cut. Try values around 100 milliseconds. Set this value higher if the soundbites sound clipped at the end.

Audio edits often produce gaps between soundbites. This is especially true when editing dialog, or splitting soundbites into small slices using the Create Soundbites from Beats command (Audio menu). Gaps of silence between soundbites can be audible and usually sound unnatural. The Smooth Audio Edits feature fills these gaps with "room tone" to mask them.

Room tone is Digital Performer’s term for a small portion of ambient sound from the original audio file (or possibly another audio file). Digital Performer can automatically search the parent audio file for a small portion of the waveform that consists of noise floor: consistent, low-level background noise that can fill silence between soundbites and crossfade seamlessly with the beginning and end of each soundbite. Or you can manually specify a room tone audio file. In either case, Digital Performer then fills the gaps between soundbites with the room tone "silence", which matches the noise floor in the soundbites enough to provide a smooth, unnoticeable transition from one soundbite to the next.

At times, the gap to be filled may sit between soundbites that are from different recording sessions with completely different noise floor characteristics. If so, Digital Performer still tries to make the transition as smooth as possible. To do so, it finds noise from each parent audio file and creates a new soundbite to fill the gap that consists of a crossfade blend from one file’s noise to the other file’s noise.

There is a soundbite attribute, accessed in the soundbite’s info pane in the Soundbites window called Bite Gain. It non-destructively raises or attenuates the overall volume of the soundbite. The range is from -140 to +80 dB. There is an additional soundbite attribute that temporarily bypasses both soundbite gain and soundbite volume automation. When bypass is engaged, the soundbite plays at its original volume. The commands in the Bite Volume and Gain sub-menu control these settings for individual soundbites. To use them, select a soundbite (either in the Sequence Editor or in the Waveform Editor) and choose the desired command below:

Clear Bite Volume: Clears the selected range in the soundbite volume curve.

Clear Bite Gain: Sets the selected soundbite’s gain to 0.0dB.

Set Bite Gain: Sets the selected soundbite’s gain to the to the value entered in the dialog.

Toggle Bite Volume Bypass: Toggles the gain/volume bypass setting for the selected soundbite(s).

Adjust Bite Volume +0.5dB: Adds a half a dB to any soundbite volume within the current selection.

Adjust Bite Volume -0.5dB: Lowers a half a dB from any soundbite volume within the current selection.

Digital Performer allows you to manipulate the pitch of audio material in the form of pitch automation data that can be edited directly in the track where the audio resides. Like volume and pan, pitch automation is applied non-destructively to track output in real-time during playback, and it it accessed from the same data layer menu for each track in the Sequence Editor.

A wide variety of pitch-related operations can be performed on audio data, from simple pitch correction using the Pencil tool, to individual note transposition, to wholesale transposing of an entire track from one mode or key to another using the Transpose command. The success of these operations depends highly on the nature of the audio material itself.

For complete details, see your Digital Performer documentation. Brief explanations of the Audio Pitch Correction sub-menu items are provided below.

Clear Pitch: Removes and changes you’ve made to the pitch curve.

Clear Pitch Control Points: Removes and control points on the currently selected portion of the pitch curve.

Quantize Pitch: If you would like to "center" one or more pitch segments, so that they are tuned exactly to their relative root pitch (to fix any notes that are a little sharp or flat), select their pitch segments and choose Quantize Pitch. Doing so centers each pitch segment with its corresponding root pitch in the pitch ruler. In general, you achieve best results from this operation if you first edit pitch segments with the mute and Scissor tools.

Scale Expression: You can scale the pitch curve by selecting the portion you wish to scale and choosing this command, or by Option-drag vertically on the pitch curve. Scaling (or dragging) upwards accentuates the existing curve, while scaling (or dragging) down flattens it. The portion of the curve that is affected by the scaling operation is determined by the end points of the pitch segment at the location where you click, or the currently selected portion of the pitch curve, if any. Scaling the pitch curve can be used for a variety of applications. Here are a few examples:

• To produce more or less vibrato in audio that already has some vibrato
• To reduce unwanted variations in pitch
• To enhance variations in pitch

Adjust Pitch Segmentation: Another way to control overall pitch segmentation accuracy is to select the desired audio and then choose Audio menu> Audio Pitch Correction> Adjust Pitch Segmentation. Move the slider to the right for more detailed segmentation; move it left for less detail. The Instruments and Vocals settings along the slider match their corresponding menu settings and produce the same results and the respective menu setting.

Pitch mode settings: Before you make individual adjustments to pitch segments in the pitch layer of an audio track, you should first choose an overall pitch mode for the audio. There are two different pitch modes: vocals and instruments. Choosing the appropriate pitch mode for the audio material you are working with can dramatically improve PureDSP’s initial representation of the pitch segments, so that you’ll have much less tweaking to do by hand, if any. To set the pitch mode for a track or soundbite, select it and then choose the desired sub-menu command (described below).

• Set Track Pitch Mode: Sets the default pitch mode for any audio material newly recorded into that track. It does NOT affect existing soundbites already in the track, or soundbites dragged into the track.
• Set Pitch Mode For Selected Bites: Sets the pitch mode and modifies the pitch segments accordingly for the currently selected audio in the Soundbites window or in any tracks.
• Set Pitch Mode For Track And Selected Bites: Applies the pitch mode to both the track and any currently selected soundbites as described above in one operation.

Enable Track Stretch: Allows you to enable Stretch for a specific audio track. When Stretch is enabled, all soundbites in the track that have been beat and tempo analyzed (and therefore have their own tempo map) will be stretched to conform to the sequence tempo, and will play in time with DP's click as well as other audio and MIDI tracks.

Disable Track Stretch: Allows you to disable Stretch for a specific audio track. When Stretch is disabled, no stretching occurs automatically, and soundbites on the track play at their original tempo and duration.

Clear Bite Stretch: Click this to clear all stretch edits for a specific soundbite.

Enable Track Pitch and Stretch Cache: Allows you to enable Pitch and Stretch Cache for a specific track. When this menu item is checked, Digital Performer stops processing audio pitch and stretch operations for the track in real time and instead caches them on disk to reduce the CPU overhead required to produce them. This processing occurs off line, in the background, so it won’t affect playback performance.

Disable Track Pitch and Stretch Cache: Turns off Pitch and Stretch Cache for a specific track. The advantage to keeping this menu item unchecked is that making edits in the track’s Pitch and Stretch could be a little more smooth and responsive, depending on how fast your computer is. The disadvantage is that the track will place higher overall demands on your computer’s CPU, especially during playback.

The Audio Beats sub-menu lets you manage Digital Performer's extensive auto beat detection features.

• Find Beats: Lets you manually initiate beat detection. If there is a selection, beats are then found only within the selection. If no selection is made, beats will be searched for in the entire file. Only searching for beats within a selection is convenient when you need beats in only a small section of the file, or if you need to update the beats within a certain section while leaving the rest of the beats in the file unchanged.
• Find Beats in All Files: Manually initiates beat detection in all files in a project.
• Adjust Beat Detection: Adjust Beat Detection command helps to eliminate beats that you may not want to include in your beat editing operations. However, instead of using a beat velocity threshold to include or exclude beats, Adjust Beat Detection uses a variety of factors to determine whether to include or exclude a beat. In most cases, this command produces best results when used after you’ve applied the Adjust Beats Sensitivity command. Adjust Beat Detection helps to fine-tune the results of adjusting beat sensitivity, if needed. Some experimentation might be required to achieve optimum results. Adjust Beat Detection is especially useful for audio that you will be quantizing and groove quantizing, as it lets you avoid quantizing portions of the waveform that are not likely to be beats that need quantizing.
• Clear Beats: The Clear Beats command removes all the beats from the audio file.
• Disable Beats under Strength Threshold: Controls how many beats are enabled or disabled in a soundbite based on their velocity threshold
• New Soundbites from Beats: Lets you split up a soundbite into pieces at beat boundaries.
• Copy Beats: CIn multitrack audio recording projects, it is often useful to take the beats from a guide track and apply them to other tracks so that their beats match the guide track. You can then apply beat-based edits or processing consistently across the tracks. For example, you might have a kick and snare track that captures the beat structure of your music perfectly, and you might wish to apply it to a highly syncopated conga track so that its beat-based edits are more consistent and in line with the overall music.
• Copy Beats as MIDI: Copies beats into the clipboard as MIDI notes with velocities that match the beat strength

When a soundbite is created, Digital Performer adds a corresponding region in the audio file with the same name as the soundbite. Digital Performer does this so that other applications can access and use the regions. Most importantly, it prevents the region from being deleted when using the Compact command. (The Compact command never deletes audio data that falls within a region in the audio file’s region list.)

Use Reload Soundbite any time that you have made changes to a region in an audio file using software other than Digital Performer and wish those changes to be reflected in the region’s corresponding soundbite in Digital Performer.

The Replace Soundbite command is similar to Reload Soundbite but gives you more flexibility. It allows you to replace a soundbite with any audio file region—even an entirely different region from another audio file. In addition to updating the soundbite’s start and end pointers, Replace Soundbite also updates the name if the soundbite is being replaced by a region with a different name.

Just like Reload Soundbite, Replace Soundbite replaces all instances of a soundbite in a Digital Performer file. Here’s an example. Let’s say that you recorded a vocal soundbite, named it Yeah!, and are using it as an effect in a mix. You have placed it fifteen or twenty times throughout the mix. During the course of the session, you decide that you would like to replace all the Yeah!’s with a different soundbite that you recorded and named Hey! Replace Soundbite makes substitutions like this easy.

The Use External Waveform Editor command is a checkable menu item. When you first choose this command, it lets you choose a third-party waveform editor, such as BIAS Peak™, as your preferred waveform editor (instead of Digital Performer’s own built-in Waveform Editor). In addition, the menu item becomes checked to indicate that it has remembered your preferred external editor. Accordingly, whenever you invoke the Edit in Waveform Editor command, Digital Performer automatically launches the third-party waveform editor and opens the audio file with the region selected for editing.

When the Use External Waveform Editor command is unchecked, Digital Performer’s Waveform Editor opens instead.