Understanding the History and Operation of Wavetable Synthesis

0Share

With so many types of synthesis technologies available, it’s hard to know which way to turn for a specific sound. Wavetables synthesis was designed to produce natural tone-like sounds and was one the first commercially available instruments to harness the power of digital sampling. In this article, we’ll explore the ins and outs of wavetable synthesis and discover why, after all these years, anyone would still want to use wavetable synthesis.

History

Wavetable synthesis has a rich history and was the first “computer-” based synthesizer and the precursor to the “Virtual Studio.” Its early incarnations were some of the first to include a built-in hard disk recorder, synthesis engine, and effects, a technological concept that would later become Steinberg’s VST.

Wolfgang Palm started building synthesizers in the early 1970s. Some of these early designs included analog synthesizers (keyboard and modular versions), sequencers, and control modules. Some high-profile artists, such as Tangerine Dream, were fans, and had custom-built systems that were used for live performance and in the studio.

"By 1977, Wolfgang Palm had developed the first commercially available synthesizer that utilized digital oscillators and a digital interface with push-buttons that could save and recall patch configurations..."

Analog synthesizers had several shortcomings at the time. Most notably, the oscillators were notoriously difficult to keep in tune and there was no way to save a patch. By 1977, Wolfgang Palm had developed the first commercially available synthesizer that utilized digital oscillators and a digital interface with push-buttons that could save and recall patch configurations. The digital oscillators not only stayed on pitch, but offered a wide palette of waveforms with different sound spectra. It was during this era that the first microprocessors became available and, by 1979, Palm published his designs and formed the Palm Products GmbH (PPG), which produced several digitally controlled instruments that were in direct competition with Oberheim and Sequential Circuits, as well as the Fairlight CMI. The most famous was the Wave series and its various permutations (PPG Wave 2, PPG Wave 2.2, PPG Wave 2.3). A great many artists championed the sound and technology, including David Bowie, Eat-Static, Electronic Dream Planet, The Fixx, Trevor Horn, Jean Michel Jarre, Art of Noise, Rush, Depeche Mode, Gary Numan, Robert Palmer, Psychedelic Furs, Talk Talk, The Cars, Ultravox, Steve Winwood, Rush, Stevie Nicks, Thomas Dolby, Pet Shop Boys, Mike and the Mechanics, and Stevie Wonder.

In 1986, the last PPG product produced was “The Realizer,” which was a DSP-based system that was nearly a decade ahead of its time. The Realizer consisted of a rack with the DSP hardware and a futuristic desktop device with a screen and freely assignable control elements. There are promotional photos of the unit with a Minimoog on the Realizer screen. Unfortunately, the Realizer never left the prototype stage because research and development was costly, and the release of the DX7 and cheaper samplers forced an end to PPG. Wolfgang Palm went on to program for Waldorf, as well as work with Steinberg on the development of the virtual studio.

"The WAVE is still considered the most advanced wavetable synthesizer and has been used by a variety of artists and musicians, including Depeche Mode, Hans Zimmer, and The Orb....."

In 1988, Wolfgang Duren, the former distributor of PPG, founded Waldorf Electronics and released the Microwave, in 1989. In 1992, the Waldorf WAVE was created, which was a deluxe version of the Microwave technology and included additional features for wavetable creation and re-synthesis. The WAVE is still considered the most advanced wavetable synthesizer and has been used by a variety of artists and musicians, including Depeche Mode, Hans Zimmer, and The Orb. Waldorf is still producing hardware synthesizers with wavetables, which adopt the many facets of analog subtractive synthesizers (filters, envelopes, LFOs, etc), but allow for wave sequencing of the wavetable oscillators.

Working Principals of Wavetable Synthesis

Wavetable synthesis is fundamentally based on periodic reproduction of a single-cycle waveform. Typically, several single-cycle waveforms are collected into a bank or table and the user programs some modulation to create dynamic movement. One of the earliest wavetables was designed to recreate a filter sweep from a Moog synthesizer. The first wave in the table contained a harmonically rich, single-cycle waveform, like a traditional analog synthesizer with no filter applied. The next single cycle waveform started to introduce the filter, thus removing some harmonics. With each single-cycle waveform, the filter was increased until, finally, the last waveform in the wavetable was a sine wave. By sweeping the wavetable, you could recreate a reasonable facsimile of an analog filter sweep. Sweeping the wavetable in either direction can be controlled in several ways, for example, by use of an LFO, envelope, pressure, or velocity. Ultimately, it didn't really sound like a Moog sweep, because everything possessed a “jingly” quality. These artifacts were what gave the PPG Wave its character and made it so famous.

Other methods of analog synthesis could be recreated, such as the pulse-width modulation (PWM) of a square wave. By using several square waves of different duty cycles, the wavetable, when swept, created the appearance of the pulse wave changing over time. Where things got interesting was the inclusion of complex single-cycle waveforms.

Misnomer

For a time, companies like Creative Labs, with its Sound Blaster family of sound cards, started using “Wavetable” to describe generic “sample playback,” which has nothing to do with the initial concept of true wavetable synthesis.

Additionally, there are similar technologies like vector synthesis, which was utilized by the Korg Wavestation, that could create similar sounds. However, the waveforms were mixed together or layered as you started to crossfade between them, which caused some phase cancellations at different frequencies. True wavetable synthesis does not mix waveforms, but interpolates them in a way without any phase anomalies. The resulting interpolated single-cycle waveform will not generate cancellations or phase beating, and results in a solid, single-oscillator waveform that only changes spectrally.

Wavetable Examples

Wavetable Env Sweep Full

Reason’s Europa is a new software-based wavetable synthesizer that was released with Reason 10 and can now be purchased separately as a stand-alone instrument.

In this audio example, I’m using a single engine with the “Complex” wavetable selected. It’s just a single note held for 4 bars. I used an envelope to sweep the wavetable slowly, which adds motion to the spectral information, without changes to the pitch or filter settings.

This is the same patch, but shifted down one octave. Notice how the harmonic content changes, as if it is a completely different wavetable.

This is another version of the same patch, but two octaves lower.

Engine Sweep with Spectral Filter

In this sound example, I’m using three engines, each with the Complex wavetable selected. Engine 2 is one octave lower, while Engine 3 is two octaves lower. Envelope One is controlling the wavetable sweep on each engine. I’ve also added the spectral filter with harmonics and routed Envelope Two to the filter frequency cutoff to add some motion. Additionally, I engaged the Unison function and added some light reverb.

Massive Wavetable Patch

Another popular and insanely powerful wavetable synthesizer is Massive, from Native Instruments. In this example, I’ve chosen the aggressive Scream wavetable for oscillator one. I’m using Envelope One and Two to change the WT-position and Intensity, respectively. Oscillator two is utilizing the Wicked wavetable and is pitched up one octave. I’ve assigned the “8 – Performer” to create some interesting motion patterns, which you can see on the bottom right of the image.

For my final example of wavetable synthesis, I offer up a ditty I wrote 15 years ago. The track was more of an experiment and a little repetitive; however, I only used the Waldorf Micro-Q synthesizer for all the parts, including the drums, and it is a great example of wavetables in use. Although the Micro-Q was billed as an analog modelling synth, it included wavetables, and the breakdown at 1:38 is a classic example of wavetable sequencing, using a random-shaped LFO.

Current Offerings

If you are looking to explore and experiment with wavetable synthesis, then you are in luck. On the hardware side, Waldorf offers the best “bang-for-the-buck” with its 16-part multitimbral Blofeld desktop and keyboard, which includes 25-voice polyphony and features authentic circuit models of analog waveforms, two wavetables from the Q and micro-Q series, and all the ROM wavetables from the WAVE, as well as the microwave II and XT and, for the first time, the upper wavetables of the original PPG Wave. If you are a Eurorack enthusiast, Waldorf also makes nw1 Wavetable Module, which features cyclic wavetable scanning with modulatable position and travel speed, and includes control of a spectral envelope with independence of pitch. Waldorf’s latest flagship offering, the Quantum, includes the latest additions from Nave, including speech synthesis and wavetable generation from audio. Other notable hardware synthesizers with wavetable capabilities include the Nord Lead 4, Novation Mini/UltraNova, DSI Prophet 12, and the Access Virus TI.

Waldorf Blofeld Keyboard

For software, Waldorf is offering the Largo, Nave, PPG 3.V, and PPG - Waldorf Edition, while other manufacturers include KV331 Audio SynthMaster, Waves Codex, Propellerhead Europa, Tone2 Icarus, and IK Multimedia Syntronik Blau. Ableton Live 10 Suite has introduced its latest synthesizer, Wavetable. I would be remiss if I didn’t include the software instruments PPG Infinite Pro, PPG Phonem, PPG WaveMapper 2, and PPG WaveGenerator, which are offered by the man himself—Wolfgang Palm.

Waldorf Largo Software Synthesizer Plug-In

As you can see, Wavetable synthesis is not all that complicated, but it can be an extremely powerful sound design tool. Hopefully, this article piqued your interest and you will delve into its immensely satisfying sonic potential. Wavetable synthesis has been around for years and is often forgotten about, but with the advent of newer and more powerful instruments, you’ll be hearing a resurgence in these sounds, for sure. I hope you have enjoyed this article on wavetable synthesis and that it helps you in your production work.

If anyone has experience working with and programming wavetable synthesizers, please share some tips in the Comments section, below.

Close

Close

Close