Algorithm selection: Saving time

Melodyne’s algorithms are optimized for particular types of material. For this reason, Melodyne selects automatically “Melodic” for a vocal or bass track, “Polyphonic” for a guitar or string track, “Percussive” for drums, and so on. These are generally the right choices. There are, however, borderline cases that are harder to categorize – for instance, a drum loop featuring pitched instruments such as a sine-wave kick or a vocoder hi-hat. Here, a polyphonic algorithm might be a better choice than “Percussive”.

So sometimes you may wish to switch the algorithm by hand. If you do so, however, any changes you have made previously to the melody, tuning or timing will be lost. A word of advice, therefore:

  • As soon as the detection is complete, consider first of all whether you should switch to a different algorithm; do this before you begin working on the blobs.

The Universal algorithm, in particular, is often a good alternative to the default choice. It is suitable acoustically for every type of audio material but breaks it down into “time slices” rather than individual notes. For tempo changes or quantizing timing, that’s perfect. Also for transposing a recording up or down the odd semitone. Furthermore, it’s an algorithm that makes very modest demands upon the computer’s processor and memory. The Universal algorithm, however, is never employed automatically; you have to select it yourself. A further word of advice:

  • Ask yourself in the case of a rhythm guitar track, for example, which is detected, by default, using the “Polyphonic” algorithm: Are you really planning to alter the chords themselves or merely their timing? If all you are going to be doing is tidying up the timing of the performance, the Universal algorithm would be a more sensible choice.

You can save time, in fact, by selecting an algorithm prior to the transfer, because whenever “Automatic” is selected under “Set Default” in the Algorithm menu, Melodyne begins its analysis of the audio file by looking to see whether or not the material is polyphonic, and it can only make this determination after a great deal of processing – wasted processing, if you know the outcome in advance.

  • So if you know the audio segment you are about to transfer is monophonic, you should set the default to “Melodic” prior to the transfer (or to “Percussive” if the material clearly falls into that category). By doing so, you will spare yourself an unnecessary wait.

From this film, you will learn more about fine-tuning Melodyne’s algorithms.
Melodyne 4 – basics: The Algorithm Inspector in Note Assignment Mode

Further details concerning the algorithms can be found in the reference section of the User Manual.
Audio characteristics and algorithms