Cubase Tutorial: Become a Power User Part 5 – Manipulating And Correcting Audio

Even the best performer won’t hit the right notes each and every time, but that doesn’t necessarily mean having to re-record an entire take. Tim Hallas explains why…

Over the last few months we have covered the basics of Cubase, looking at everything from the entering of MIDI data through to audio recording. But having covered the process of getting data into the software, what can we do with it afterwards? Over the next couple of months I will look at some of the features available to you in the different editing sections of Cubase.

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We’ll kick off by exploring the features available within the Sample Editor. This is the default window for editing audio within Cubase and it is accessed by double-clicking on any piece of audio within the Arrange window. Do that and it will magically appear.

We’ll first look at the imaginatively named VariAudio, AudioWarp and Definition & Hitpoints sections of the Sample Editor. These are all based around the premise that audio can be treated and edited like MIDI data – by changing the time or pitch of notes. The VariAudio section enables alterations in pitch to be performed on a recording. Obviously, this works only on monophonic sounds, so don’t go trying it on a piano line (while some versions of Melodyne do enable you to change notes within chords, Cubase doesn’t). AudioWarp changes note positioning and is essentially the tool we use to quantise audio in time. Hitpoints is the function that analyses the audio file for AudioWarp, and can treat the resulting information in a variety of ways for other purposes, too.

These are quite advanced processes, and Cubase has had them for longer than some other DAWs, so they will be fairly familiar technologies to some users. However, they are some of the tools that require the most tweaking to use accurately. It is therefore worth experimenting with them before you use them on an important project.

These are the tools that can transform an amateurish recording into a professionally edited-sounding track, and although these processes might seem long-winded – I once spent over eight hours correcting the drum timing on a project, and that is by no means long – the end result gives the track that really tight sound that you can get only in a recording.

Definition and Hitpoints

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1: Definition is the function that determines information about the sample being worked on. To open it, double-click on an audio file within the Arrange window and select the top tab on the left-hand side. Hitpoints can be found in the same place (the fourth tab down) and contains all the controls for analysing the peaks in the file.

2: From the Definition tab, select the Auto-Adjust control – it will analyse the file’s tempo and so on. This was actually incorrect in my file, but it can be changed at the top in the box labelled Tempo. This works best if the track was actually recorded to a click as it can then synchronise the file to the grid automatically. Any errors can be corrected manually later.

3: The Hitpoints tab contains controls for analysing the audio. Start by adjusting the threshold – this creates two lines over the waveform that indicate at what volume level the software will create a Hitpoint and below what volume it will be ignored. Do this by eye, as it will be clear where the peaks are in your file.

4: You can move the Hitpoints if the software has put one in the wrong place by grabbing it with the cursor and moving it to the right piece of audio. This way, it won’t quantise a bit of silence! Preparation here is important as it will affect the output when the information is transferred to other areas of the software.

5: To use this information elsewhere, select the portion of the audio file you want to export and then select the relevant button in the Hitpoint tab. I am going to create MIDI notes so that I can double them with another part in the Arrange window at a later date. Obviously, this can be used to generate Warp markers – we’ll get to that shortly…

6: If you get in a muddle with Hitpoints and Markers and need to restart everything, there is a Remove All button that gives you a clean slate to work from. I often find myself performing this process two or three times to get it absolutely right, particularly when adjusting the threshold settings.

AudioWarp

1: AudioWarp is accessed via the second tab to the left in the Sample Editor and can be used in several ways. The first is freehand – select the Free Warp button to the left. This allows you to click anywhere on the waveform and drag that point around in time. This has disadvantages in that, without anchoring other points, it will move the entire waveform.

2: To add extra markers, click on each point where you want a marker (the beginning of a note and so on) and move them around as each note requires. This prevents you from moving the entire waveform as it locks each marker in place and won’t change the waveform beyond that point when editing.

3: To speed up the process, the Hitpoints tab has a button labelled Create Warp Markers. Select the area of the waveform that you want to analyse and press that button – it generates Warp markers in the AudioWarp tab. When you go back to that tab they should be created in the AudioWarp tab and ready to adjust.

4: It is worth setting the grid that you intend to work with to a suitable resolution. This allows you to adjust the notes to the appropriate beat of the bar. Typically, select the smallest resolution that you used (1/4 notes, in my case) so you can move the AudioWarp markers into line with them to create a tight performance.

5: The Musical mode button places the Warp markers into time automatically based on analysis from the Definition tab. This can be triggered by simply clicking on the button on the left-hand side under the AudioWarp tab. This saves you from dragging the points around. However, it isn’t always entirely accurate, so it’s worth listening to the finished result and editing any incorrect ones by hand.

6: If your piece has a swing to it, the other slider in Musical mode has got you covered. This moves the second quaver of each pair by varying amounts depending on how far the slider is to the right. The further the slider, the harder the swing. It actually physically moves the waveform, so it can be seen as you are adjusting.

VariAudio:

1: VariAudio can be found by double-clicking on any audio file and selecting the VariAudio tab from the left-hand side of the Sample Editor; the software will analyse the pitches when the button labelled Pitch & Warp is clicked. When illuminated, small blocks appear in-line with the piano keyboard above the related waveform. It is worth zooming in for better precision.

2: Once Cubase has analysed the music and you can see the blocks clearly, select one of the blocks and try moving it around. This should change the base note to what it should be and can correct large discrepancies in pitch (if the performer has played the wrong note!). It’s a rough-and-ready way of making the part correct.

3: When the notes are correct, the Quantise slider in the Inspector panel can be adjusted to bring the note closer to concert pitch. No performer, no matter how good, is going to be 100% accurate with their intonation every time. The further to the right it slides, the more precise it becomes. Adjust this until you are happy with it.

4: The other slider is the control labelled Straighten Pitch. This is used to remove variation in a performer’s pitch, such as vibrato or natural slides. Although it is unlikely that you’ll want to remove all of these nuances from a performance, it is possible they might need controlling (particularly in backing vocals). The further to the right this slider is, the less deviance there is from the correct pitch.

5: If the analysis is wrong and Cubase hasn’t spotted a note change, you can split the note and make a separate one. Select the Segments button to the left and hold the cursor over the relevant pitch block at the bottom – it will turn into a pair of scissors. When clicked, this splits the block into two at the point you choose. You can then alter the notes separately.

6: The Extract MIDI button takes the analysed pitch data and generates a MIDI file from it in the Arrange window. Click it to open a pop-up window and choose whether to include dynamics and pitch-bends. This can be used to double-up parts or replace them entirely if a performance is unsalvageable.

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