Vibrato

Vibrato is a tone-based plug-in and the first of several types of “modulation” plug-ins I’ll cover.

Simply put, modulation is the manipulation of audio over time. Now, this might sound a lot like automation, which I’ve talked about before, but the two are different in that automation is controlled manually by the producer, while modulation is set within the parameters of a plug-in.

In general, automation allows the producer to make specific, individual choices at different points in time on the track, while modulation is typically used as a lasting effect, sometimes for the entire duration of the track.

A modulation plug-in operates by cycling through a particular set of values at a particular rate, based on how the parameters of that plug-in have been set. These parameters can be tone-based, like those of a phaser or a vibrato, volume-based, like those of a tremolo, or both tone- and time-based, like those of a chorus or a flanger. I’ll discuss all of these plug-ins over the next few entries.

Because of its popularity as a built-in effect on many electric instruments and instrument amplifiers, a lot of guitarists and keyboardists will already be familiar with vibrato. Most vocalists will also be aware of the term, as “vibrato” is a natural singing technique that operates by the same mechanism as the plug-in.

When a vocalist introduces vibrato into a note, he or she begins to alternate between a subtle increase and a subtle decrease in pitch, quickly cycling from slightly above the pitch of the original note to slightly below the pitch of the original note and back again. Because of the relatively fast rate of this cycle, the listener continues to perceive the original, central pitch, but the technique tends to “iron out” the natural flaws of the human voice and add “movement” to the performance.

A vibrato plug-in does the same thing, though digitally, to the track on which it is used.

The same effect could be achieved by automating the parameters of a pitch shift plug-in (which we'll cover in the future), up and back down again, many times over the course of a track, but at the rate that a vibrato can work, you can imagine how making so many automation edits could become quite tedious. Modulation plug-ins are designed to do the work for you.

A vibrato plug-in will usually have at least he following two parameters: “depth” and “rate.”

Depth determines the degree to which the pitch is being bent away from its original position. Rate determines how quickly the vibrato will complete one cycle, meaning that the original pitch has been bent up, then down, and then returned to its original position.

Vibrato, like other modulation plug-ins, is a creative tool and can be considered as early as the writing stage of a song, but it can also be used to sweeten a mix when the basic tools just aren’t cutting it.

Just remember, vibrato can alter the sound of a track quite a bit, so as a general rule, and as I advised with distortion, use it sparingly.