The Operator FM Synth
The available controls in Operator are based on the signal path of a hardware synthesizer, such as the Synclavier or the Yamaha DX-7. When a note is triggered, a digital waveform is played back to create the basic note. Operator has over two dozen to choose from, or you can draw your own into the main display window using the pen tool. The amplitude waveform, controlling the progressive volume of the sound, is drawn with a standard ADSR line diagram, representing the attack, decay, sustain and release of the sound.
The left side of the main display houses four separate frequency modulation controls. These are the primary controls for reproducing the classic FM sound. Each control controls the relation of the oscillator frequency to the note pitch. Allowing the user to create a variety of harmonics and overtones to add complexity and texture to each note. This method of sound generation is identical to the one used in hardware FM synthesizers
As the Operator mimics a digital device, rather than an analog one, your computer is able to perform the exact same mathematical process that occurs inside a hardware unit. This produces a very authentic approximation of the original machines, and using the same types of controls and parameters will make the device easier to use for those already familiar with existing synthesizers. Synths such as this one are a common inclusion in most audio software packages.
The Ableton Live Operator presets are designed to show off all the features of the synth. In particular, its ability to emulate the classic synthesizers on which it is based. There are emulations of classic signature sounds, and a number of "retro" patches.
They're also intended to familarize you with the effects of altering the controls. Having a variety of pre-made sounds will allow you to instantly observe the impact that altering a particular control will have. To allow further experimentation, Ableton includes a "Hot Swap" button on the title bar of Operator. Enabling Hotswap mode allows you to instantly switch between presets while the sequencer is playing, making it useful for browsing a variety of different sounds and hearing them in context of a song.
This is an important category for this particular variety of synthesizer. Digital FM synthesizers were the first practical, affordable instruments that were capable of creating sounds that gradually evolved over time. Early analog synths needed additional oscillators to achieve these effects, not to mention an extra pair of hands to operate the controls!
As a result, sweeping pads and slowly morphing sounds became synonymous with this particular type of synthesizer. The majority of Abelton Live Operator presets are labeled as "Ambient." This is understandable as the majority of them are minimalist pads and moving textures, intended to create a background noise floor that acts as a bed for the rest of the song. They react best to simple two or three note chords, held for a few bars to allow their gradual mutation to take effect. Many of them have very long attack times, often taking three to five seconds to appear after the key is pressed.
Emulation of real-world instruments
There are also a number of Ableton Live Operator presets that are intended to mimic the sound of "real-world" acoustic instruments. Pianos, guitars and orchestral strings are all represented in the Operator factory presets. What's important to bear in mind, is that the Operator is really a "retro" unit. This particular synthesis technology has been commercially available since the early 80s, and much more advanced and realistic synthesized instruments are now available.
The Operator patches are meant to mimic the sound of one of those classic hardware synthesizers, mimicking an acoustic instrument. When you play a guitar sound with the Operator, it is mimicking an FM synth mimicking a guitar, rather than just the sound of an actual guitar.
Classic Analog Sounds
The Operator preset bank includes a selection of "Classic" analog sounds, divided into the generally accepted categories of Bass, Pad, Lead and Chord. As with the real-world instruments, these are a "sound-alike" interpretation of an analog synth. They were often included as factory presets on digital hardware synthesizers, and understandably sound slightly different to the real thing. They are likely included for the sake of authentically reproducing the factory preset list of the original instruments, and because their distinct sound is unique to those original FM synths.
The version of Operator included with Ableton Live 8 allows the different modules to be connected in various different patterns. This means that the envelope applied to each section will trigger at a different point if it is delayed by connecting a similar envelope in front of it in the chain. Setting the envelopes to contrasting values, and alternating the way they are connected, can create rhythmic pulses and patterns that reinforce the beat of a song, and provide counterpoint to its rhythm.
The effect is similar to an analog arpeggiator, found on older analog synthesizers. They're a popular method of quickly fattening up a song and making it sound more frantic and detailed.
The "Components" bank of presets contains the raw, unaffected waveforms that are used as the building blocks for all the other sounds. The filter, LFO and frequency modulation controls are all disabled by default. These presets contain unprocessed sine, saw and square waveforms, as well as a few slightly more unusual ones. The idea here is to give you a foundation building block for creating your own presets. Once you've finished exploring the other factory presets and familiarized yourself with the controls, you can use what you've learned to take a simple sine tone, and gradually twist and manipulate it into something thick and richly textured. Work through the frequency modulators and experiement with the envelope controls, you'll soon create a striking FM-style preset of your own.
The Ableton Live Operator preset sounds are designed to show what the unit is capable of, and suggest applications for its use. The Operator is not really capable of producing highly realistic reproductions of acoustic instruments, but the available presets show the types of sounds it can create. They act as a tour of the unit's capabilities and its limitations, aiding you in making the appropriate instrument choice when you're trying to chase down a sound in your head.
- Ableton; Operator Specifications, http://www.ableton.com/operator