Introduction to Synthesizer Programming

Introduction to Synthesizer Programming

3 October, 2007 | 6.03AM

• Written by: francispreve
• Filed under: Music News: guide to synthesis, synthesis, synthesizer

To kick off our first series on music production techniques, we’ll begin by going deep into synthesizers. Sure, we all know that synths are musical instruments that form the essence of all club music (a broad statement, but that’s a fact).

But did you know that there are upwards of five distinct types of synthesis technology that serve as the basis for most software and hardware synths?

When producers talk of a “synthesizer” they are generally referring to analog synthesizers like Moogs, Prophets and classic Roland gear, but that’s only one type of synthesis.

In the pantheon of synthesis techniques, there are quite a few methods for creating new sounds that can be played via keyboards, drum pads, even MIDI-fied wind instruments and guitars.

So, to get everyone warmed up, here’s a round-up of the most common sound generation tools available today.

Types of synthesis

Each type of synthesis has its own strengths and weaknesses.

Analog synthesizers are ill-suited for creating realistic pianos and orchestras, but are amazing for electronic basses and leads – and that’s just scratching the surface.

FM synthesizers are also superb for creating exotic electronic textures, but have a more “digital” sound than the more common subtractive softsynths.

Then there’s physical modeling, which is theoretically capable of emulating the warmth and complexity of acoustic instruments, though the technology is still relatively new (compared to analog, sampling and FM) and requires a fair amount of computational power to derive its sound.

Here’s a summary of these various sound generation systems, along with explanations of their strengths, weaknesses and applications.

Sampling

By now, pretty much everyone’s heard of sampling, as it’s probably the most common form of synthesis on the market – embedded into everything from mobile phones to online gaming soundtracks.

Samplers can be found in a massive range of forms, from drum machines (like Akai’s legendary MPC series) to advanced software tools like Ableton Live, which blurs the line between a performance instrument and a recording studio.

Akai’s vintage S1000 is a legendary sampler [on right] is favoured by countless producers for its easy-to-navigate LCD interface.

How it works: Samplers work by converting analog voltages (the audio signal) to digital information, which can then be manipulated to create loops, recreate traditional instruments like piano, or generate single hits such as drums, percussion and acoustic sound effects.

Technically, the process is fairly straightforward, with two main criteria — sampling rate and sample resolution — that determine the quality of the digital recording.

Sonically, the sampling rate governs the overall frequency range (low bass to trebbly highs) of the recording, whereas the sampling resolution, sometimes called bit depth, determines the dynamic range (from quiet to loud) of the sample.

Pros: Sampling is the essential technology for looping “found” musical segments, as well as creating near perfect representations of acoustic instruments and custom drum kits. It’s great for realistic sounds.

Cons: Not ideal for dynamic morphing textures, unless used in combination with other synthesis technologies.

Subtractive

Subtractive synthesis is the oldest form of synthesizer technology and serves as the basis for the majority of both hardware and software based instruments.

For the record, all analog synthesizers are based on subtractive principles, but that’s not to say that analog is the only type of synthesis that relies on this approach.

Generally, most of the other forms of synthesis — including FM and sampling — include a subtractive processing section to further modify the results of their respective tone generation approaches.

How it works: Subtractive synthesis works by taking a harmonically rich oscillator source — often a simple waveform like sawtooth or square — then subtracts specific ranges of frequency content via the use of filters.

Dynamic and morphing effects are created by changing the properties of the oscillators and filters by applying envelopes, LFOs (low frequency oscillators) and MIDI controller data to their various parameters.

If this sounds really complicated, it’s not.

Here’s an analogy. Think of your CD decks as the original source (like the oscillator) and your mixer’s EQ as the filter section.

Taken a step further, some old school techniques like “transforming” (rhythmically moving the A-B slider of a mixer) have much in common with LFOs. Approaching it from this perspective makes it easy to get a handle on the essentials with minimum head scratching.

Part of Reason’s popularity is the classic sound of its Subtractor synthesizer [right], which is capable of emulating many analog textures.

Pros: Classic analog and vintage sounds. Huge selection of capable hardware and software instruments. Easiest method of synthesis to master.

Cons: Not suited to realistic sounds like piano and orchestras (although analog strings are a notable exception).

FM (Frequency Modulation)

Slightly less common, but still with a devoted following is Frequency Modulation synthesis.

Originally introduced to the mainstream in the 1980s – thanks to Yamaha’s affordable line of DX synthesizers – FM has evolved into much more complex tools, such as Native Instruments’ FM8 and Ableton’s Operator softsynths.

Modern FM synthesis fans rely on Native Instruments’ powerful FM8 softsynth [right], which also excels at recreating vintage Yamaha DX7 sounds.

How it works: The essential principle behind FM synths is extreme vibrato, like the quivering pitch of an opera vocalist, but much faster so that it operates in the audio range.

In an FM device, an array of interdependent oscillators — called an ‘algorithm’ — are tuned to different harmonics and/or frequencies.

From there, these oscillators (known as operators) interact with each other, generating harmonic spectra that can be used to emulate organic/acoustic sounds or create bizarre digital textures.

Pros: Excellent for percussive, metallic sounds like bells, xylophones and plucked instruments, as well as punchy basses and exotic lead sounds.

Cons: Some producers dislike the sound, calling it digital and cold.

Next Week

Our guide to synthesis continues next week with a look at the remaining types of synthesis, physical modeling and exotica, plus we take a look at the longest running debate in electronic music production - Softsynths vs. Hardware.

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