Introduction to Quantizing

Article by: Troy Woodfield

Tips from: Paul Kellett



This article introduces the concept of MIDI "Quantizing". We will begin by defining the term "Quantizing" and then we'll look at the different types of quantizing offered in Cubase. This article is based upon Cubase VST 3.553. The information may also be useful for those who use other MIDI sequencers. Where I come from, Quantizing is spelt "Quantising", however, to avoid confusing our American brothers, and sisters, this article uses the word: "Quantizing".


Most MIDI sequencers (eg: Cakewalk, Logic and Cubase) offer a "Quantize" function. This quantizing functionality was initially introduced as a means of allowing musicians to record music and then automatically correct the timing. For example, if you play four notes, and the fourth note is slightly out of time, the quantize function can automatically re-align the fourth note. As a result, quantizing has helped thousands of out-of-time musicians slap their notes back into the correct timing. The problem with this basic quantising approach is that it assumes that every song written should use perfect timing, as based on the metronome. In reality this is not always the desired outcome. Some musicians intentionally express themselves using irregular or mismatched timing. The software developers responded by providing quantising which only adjusted notes which were significantly out-of-time. This left the "slighty-out-of-time" notes alone, thereby creating a more natural "human" feel to the music. The next quantising breakthrough occurred as a result of musical research. By analysing world-class musical performances, it was identified that some musicians repeatedly play particular notes off-time. A simple example: perhaps the 3rd note is played slightly early and the 4th note slightly late. This timing trait (or Groove) can be extracted and imposed onto someone elses music. We'll look at this later in the article. In summary: Quantizing was introduced primarily as a means of correcting timing, but it has evolved into a tool, which is useful for shaping and enhancing the timing of a song in a more sophisticated manner.

The Quantizing Value

The first step, when using Quantize, is to specify the Quantize value. The quantize values are: 1 ... Pull notes to nearest whole beat. 2 ... Pull notes to nearest half beat. 4 ... Pull notes to nearest quarter beat. etc. You need to select a quantize value which suits your song. For example, if you are writing a four-to-the-floor Hip Hop track, then set your Drum to use a quantising value of 4, to move each individual drum hit so it falls exactly on the beat.

Cubase Quantizing Options

Cubase VST 3.553 offers several Quantizing methods. These are accessed under the pulldown menu: Functions. 1. Note on Quantize This is the basic quantize approach. This type of quantizing moves the notes to the closest quantize value, without changing the length. For example, with a quantize value of 1, the notes are moved to the nearest whole beat. The before and after (quantising) is shown below. Here, two drum hits are pulled to the first beat while the other two beats are pulled to the second whole beat, as it is closer. <1> 2 3 4 <2> Drum before: x x x x Drum after: x x 2. Over Quantize This type of quantizing moves the note, as above, but it also tries to detect chords and keeps them together while moving notes about. ie: It is more musically intelligent. 3. Iterative Quantize This type of Quantizing moves the notes a certain amount towards the closest quantize value, if they are not very close to it already. How much the notes are moved, and what is considered "already close to the Quantize value", is set using the "Strength" and "Don't Q" parameters in the: Functions - Setup Groove pull-down menu. The idea here is that you set the strength value, which specifies how strongly you want to pull the note. eg: If the strength is set to 60%, then Cubase will move the note 60% of the way towards the Quantise value. Tip: You can start with a small Strength value and then listen to the result. If you don't like the result, increase the Strength value slightly, so the notes are moved a little closer to the Quantise value. By slowly tweaking the Strength value, you gradually alter the result until you get the desired outcome. The "Don't Q" option (Don't Quantize) is used to specify which notes are close enough to the Quantize value and need not be moved. You specify a number (of ticks) and any notes under that distance from the Quantize value will not be moved. 4. Analytic Quantize This type of Quantize should be used on complex input, such as parts with mixed straight notes and triplets and glissandos. The Quantize value is used, but not rigorously, more to give the program an "impression" of how you want it ...and that's all the information I have on it. 5. Groove Quantize Earlier in this article, I stated that researchers have been able to capture the timing traits of world-class performers and to apply them as a kind of timing template which can be imposed onto our songs. Ie: Here's my song, can you please alter it to fit into someone elses timings (Groove). This type of Quantizing is not used to correct mistakes, but rather to impose a certain feel on the music. Cubase comes with a number of Grooves, but you can also load new Grooves from disk or create your own. The Groove Quantize menu item opens a sub-menu, where you can select a Groove. Events are then Quantized according to the selected Groove Map. The Quantize value is used in a special way: If you for example set it to eighth notes, only eighth notes and "bigger" in the Part will be affected, sixteenth notes and "smaller" remain unaffected. You can Save and Open sets of Groove maps from Disk. Groove files have an extension of *.GRV. Cubase can only load one set of Grooves at a time. You can also edit Grooves and make up your own.

Changing an existing Groove

If you want to change an existing Groove, but also keep the original, unchanged version intact: 1. Select: Functions - Setup Grooves 2. Select the Groove you want to start with. 3. Open it in an editor by pressing the Edit button. 4. Select: Edit - Select - Select All. 5. Select: Edit Copy. 6. Close the editor, 7. Select: Functions - Setup Grooves 8. Click on the New button. This creates a new Groove. 9. Select the new Groove (NewGroove). 10. Click: Edit to open the editor, with the new Groove selected. 11. Select: Edit - Paste. 12 Edit the notes as desired. 13. To change the name of the new Groove (it’s initially called NewGroove), double click on it in the Groove pop-up in the Setup Grooves dialog, and type in the new name.

Freeze Quantize

This Cubase command makes the Quantization permanent. After using this command it is no longer possible to Undo Quantize. It is important to understand that all Quantize operations (except Iterative Quantize) use the original, un-quantized music to determine how notes should be moved. If you want to Quantize in several steps, you have to Freeze Quantize between each step for the operations to have the desired effect. The Freeze Quantize option appears under: Function - Free Quantize.

Removing Quantizing

Cubase offers an "Un-Do Quantize" option (Pull-down menu: Functions - Undo Quantize). This allows you to play with quantize settings and then remove them if you don't like the results.

Quantizing Tips from Paul Kellett

When quantizing samples, remember the sample start point setting also affects the timing. It's useful to edit the start point while listening anoctave or two down so you can hear it clearly. Alternatively, you can adjust the start point to change the feel of an individual sound without affecting everything else like applying a 'groove' quantize does. Some sounds (like acoustic kick drums) start slightly before the beat, so trimming the start point can make a 'Plop' sound instead of a nice 'ttThud' - Try off-setting the track back in the sequencer, then adjusting the sample start point to get it exactly on the beat. For the tightest quantizing, you need to bypass MIDI and use hardware (like an MPC) or software that produces a WAV file (like fruityloops). Tempo readouts on sequencers are not completely accurate - if you are trying to match MIDI to a drum loop try adjusting up or down a little for the best feel. If it's not working, cut the loop up into 2 or 4 (or more) and trigger each piece (or use ReCycle) - you'll get a lot more control. Also remember that more resolution (ticks per quarter note) doesn't mean more accuracy: * -Good timing accuracy * * Analogue hardware (nanoseconds) * Digital hardware, software synths (to nearest sample - microseconds) * Low-tech sequencers - Atari, DOS (within a millisecond) * Mac and Windows MIDI sequencers (a few milliseconds) * Combined MIDI+Audio sequencers (a few milliseconds most of the time) *-Bad Timing accuracy Sometimes applying a 'groove' quantize is too much - try just moving one or two kicks by a few ticks and leave everything else alone (don't move the main beats, but move the off-beats a little towards or away from the main beats) or just move all the snares a little early or late.

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