Wavetable synthesis

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Wavetable synthesis is a sound synthesis technique used to create periodic waveforms. Often used in the production of musical tones or notes, it was developed by Wolfgang Palm of Palm Products GmbH (PPG) in the late 1970s [1] and published in 1979, [2] and has since been used as the primary synthesis method in synthesizers built by PPG and Waldorf Music and as an auxiliary synthesis method by Ensoniq and Access. It is currently used in software-based synthesizers for PCs and tablets, including apps offered by PPG and Waldorf, among others.

Periodic function Function that repeats its values in regular intervals or periods

In mathematics, a periodic function is a function that repeats its values in regular intervals or periods. The most important examples are the trigonometric functions, which repeat over intervals of 2π radians. Periodic functions are used throughout science to describe oscillations, waves, and other phenomena that exhibit periodicity. Any function that is not periodic is called aperiodic.

Musical tone sound with a typical pitch; steady periodic sound;characterized by its duration, pitch, intensity (or loudness), and timbre (or quality)

Traditionally in Western music, a musical tone is a steady periodic sound. A musical tone is characterized by its duration, pitch, intensity, and timbre. The notes used in music can be more complex than musical tones, as they may include aperiodic aspects, such as attack transients, vibrato, and envelope modulation.

Musical note Sign used in musical notation, a pitched sound

In music, a note is the pitch and duration of a sound, and also its representation in musical notation. A note can also represent a pitch class. Notes are the building blocks of much written music: discretizations of musical phenomena that facilitate performance, comprehension, and analysis.

Contents

It was also independently developed in a similar time frame by Michael McNabb, who used it in his 1978 composition Dreamsong . [3] [4]

The concept of multiple discovery is the hypothesis that most scientific discoveries and inventions are made independently and more or less simultaneously by multiple scientists and inventors. The concept of multiple discovery opposes a traditional view—the "heroic theory" of invention and discovery.

"Dreamsong" is a 1978 recording created by American computer music musician and composer Michael McNabb at the Center for Computer Research in Music and Acoustics in Stanford University. The composition has been discussed by numerous composers and book authors, one of them including Adrian Moore who labeled it a "pioneering work" of electroacoustic music. It is significant for being one of the earliest examples of works that combine natural and non-natural "new" sounds in a sophisticated manner with digital processing. MUS10, a compiler developed from Max Mathews' Music IV synthesis software that had a huge amount of flexibility in designing and synthesizing sounds, was used for the instrument design and synthesis of "Dreamsong", a project primarily intended to create an unlimited amount of obtainable new sounds.

Principle

Wavetable synthesis is fundamentally based on periodic reproduction of an arbitrary, single-cycle waveform. [5] In wavetable synthesis, some method is employed to vary or modulate the selected waveform in the wavetable. The position in the wavetable selects the single cycle waveform. Digital interpolation between adjacent waveforms allows for dynamic and smooth changes of the timbre of the tone produced. Sweeping the wavetable in either direction can be controlled in a number of ways, for example, by use of an LFO, envelope, pressure or velocity.

Waveform the shape and form of a signal such as a wave moving in a physical medium or an abstract representation

In electronics, acoustics, and related fields, the waveform of a signal is the shape of its graph as a function of time, independent of its time and magnitude scales and of any displacement in time.

In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a modulating signal that typically contains information to be transmitted. Most radio systems in the 20th century used frequency modulation (FM) or amplitude modulation (AM) for radio broadcast.

Interpolation method for constructing new data from known data

In the mathematical field of numerical analysis, interpolation is a method of constructing new data points within the range of a discrete set of known data points.

Many wavetables used in PPG and Ensoniq synthesizers can simulate the methods used by analog synthesizers, such as Pulse Width Modulation by utilising a number of square waves of different duty cycles. In this way, when the wavetable is swept, the duty cycle of the pulse wave will appear to change over time. As the early Ensoniq wavetable synthesizers had non resonant filters (the PPG Wave synthesizers used analogue Curtis resonant filters), some wavetables contained highly resonant waveforms to overcome this limitation of the filters.

Analog synthesizer synthesizer that uses analog circuits and analog computer techniques to generate sound electronically

An analogsynthesizer is a synthesizer that uses analog circuits and analog signals to generate sound electronically.

Square wave

A square wave is a non-sinusoidal periodic waveform in which the amplitude alternates at a steady frequency between fixed minimum and maximum values, with the same duration at minimum and maximum. Although not realizable in physical systems, the transition between minimum and maximum is instantaneous for an ideal square wave.

Duty cycle fraction of one period in which a signal or system is active

A duty cycle or power cycle is the fraction of one period in which a signal or system is active. Duty cycle is commonly expressed as a percentage or a ratio. A period is the time it takes for a signal to complete an on-and-off cycle. As a formula, a duty cycle (%) may be expressed as:

Confusion with sample-based synthesis (S&S) and Digital Wave Synthesis

In 1992, with the introduction of the Creative Labs Sound Blaster 16 the term "wavetable" [6] started to be (incorrectly) applied as a marketing term to their sound card. However, these sound cards did not employ any form of wavetable synthesis, [7] but rather PCM samples and FM synthesis. S&S (Sample and Synthesis) and Digital Wave Synthesis was the main method of sound synthesis utilised by digital synthesizers starting in the mid 80's with synthesizers such as Sequential Circuits Prophet VS, Korg DW6000/8000 (DW standing for Digital Wave), Roland D50 and Korg M1 through to current synthesizers.

Sound Blaster 16

The Sound Blaster 16 is a series of sound cards by Creative Technology. They are add-on boards for PCs with an ISA or PCI slot.

Pulse-code modulation (PCM) is a method used to digitally represent sampled analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio applications. In a PCM stream, the amplitude of the analog signal is sampled regularly at uniform intervals, and each sample is quantized to the nearest value within a range of digital steps.

User wavetables

The creation of new wavetables was previously a difficult process unless supported by specialized editing facilities and (near) real-time playback of edited wavetables on the synthesizer. Such editors often required the use of extra hardware devices like the PPG Waveterm or were only present in expensive models like the Waldorf WAVE. More commonly, pre-computed wavetables could be added via memory cards or sent to the synthesizer via MIDI. Today, wavetables can be created more easily by software and auditioned directly on a computer. Since all waveforms used in wavetable synthesis are periodic, the time-domain and frequency-domain representation are exact equivalents of each other and both can be used simultaneously to define waveforms and wavetables.

Palm Products GmbH audio synthesizer company

Palm Products GmbH was a highly regarded manufacturer of audio synthesizers. Founded and owned by Wolfgang Palm, PPG was located in Hamburg, Germany and, for 12 years from around 1975 to 1987, manufactured an acclaimed and eclectic range of electronic musical instruments, all designed by Palm.

Waldorf Music manufacturer of synthesizers

Waldorf Music is a German synthesizer company. Best known for the Microwave wavetable synthesizer and Q virtual analogue synthesizer lines developed and released by Waldorf Music AG, the original company declared insolvency at a German court on 5 February 2004. In Summer 2006 a new company Waldorf Music GmbH was officially established, although it is not a legal successor to the original company.

Practical use

During playback, the sound produced can be harmonically changed by moving to another point in the wavetable, usually under the control of an envelope generator or low frequency oscillator but frequently by any number of modulators (matrix modulation). Doing this modifies the harmonic content of the output wave in real time, producing sounds that can imitate acoustic instruments or be totally abstract, which is where this method of sound creation excels. The technique is especially useful for evolving synth pads, where the sound changes slowly over time.

It is often necessary to 'audition' each position in a wavetable and to scan through it, forwards and backwards, in order to make good use of it, though selecting random wavetables, start positions, end positions and directions of scan can also produce satisfyingly musical results. It is worth noting that most wavetable synthesizers also employ other synthesis methods to further shape the output waveform, such as subtractive synthesis (filters), phase modulation, frequency modulation and AM (ring) modulation.

Table-lookup synthesis

Csound's lookup table (f-table), closing up the data at addresses 63 through 67 (based on Figure 2.1 on Nelson 2000).jpg
An example of lookup table, where the data at addresses from 63 to 67 are zoomed.
(based on Figure 2.1 on Nelson 2000)

On Csound, it is called f-table (function table), and used for various purposes including: wavetable-lookup synthesis, waveshaping, MIDI note mapping, and storing ordered pitch-class sets. [8]

CsoundSineTable.png
An example of the content of f-table visually shown: a single-cycle sinusoidal wave.

Table-lookup synthesis [9] (or Wavetable-lookup synthesis [10] ) ( Roads 1996 ) is a class of sound synthesis methods using the waveform tables by table-lookup, called "table-lookup oscillator" technique. The length of waveforms or samples may be varied by each sound synthesis method, from a single-cycle up to several minutes.

Terminologies

The term "waveform table" (or "wave shape table" as equivalent) is often abbreviated to "wavetable", [11] and its derive term "wavetable oscillator" [12] seems to be almost same as "table-lookup oscillator" mentioned above, although the word "wave" (or "waveform", "wave shape") may possibly imply a nuance of single-cycle waveform.

However, a derive term "wavetable synthesis" seems slightly confusing. In a natural usage of words, its original meaning is basically same as "table-lookup synthesis", [13] [14] [12] and possibly several actions on waveform(s) may be expected, [15] as seen on a paper about Karplus–Strong string synthesis [16] (a simplest class of "wavetable-modification algorithm" known as digital waveguide synthesis [17] ). Then in the late-1970s, Michael McNabb [3] [4] and Wolfgang Palm [18] independently develop the multiple-wavetable extension on the table-lookup synthesis [note 1] which was typically used on PPG Wave and known with wavetable sweeping, [19] and it was later referred as "multiple wavetable synthesis" by Horner, Beauchamp & Haken 1993. [20] Simultaneously since late-1970s, also the sample-based synthesis using relatively long samples instead of single-cycle waveforms, have become influential by the introductions of the Fairlight CMI and E-mu Emulator.

Background

On the above four terminologies for the classes of sound synthesis methods, i.e.,

  1. Wavetable synthesis [12] original, generic meaning (i.e. a single-cycle table-lookup synthesis).
  2. Multiple wavetable synthesis [20] developed by McNabb and Palm, typically used on PPG Waves.
  3. Wavetable-modification algorithm [17] including digital waveguide synthesis.
  4. Sample-based synthesis

if these had been appropriately used to distinguish each other, any confusions could be avoided, but it seems failed historically. At latest in the 1990s, several influential sample-based synthesis products were marketed under the trade names similar to "wavetable synthesis" (including Gravis Ultrasound wavetable card, Creative Wave Blaster wavetable daughterboard, and Microsoft GS Wavetable SW Synth), and these confusions have further affected on the several industry standards (including MPEG-4 Structured Audio algorithmic and wavetable synthesis, [21] and AC97 optional hw acceleration wavetable synth [22] ). As a rebound of these, at the latest since the mid-2000s, a new confusion seem to begin flourish. Merely a subclass of generic wavetable synthesis, i.e. McNabb and Palm's multiple wavetable synthesis, tends to be erroneously referred as if it was a generic class of whole wavetable synthesis family, exclusively. [23]

As a background of these confusions, the difficulties of maintaining the consistencies between concepts and terminologies during the rapid developments of technology, may be significant. And it is a reason why this slightly classical terminology "Table-lookup synthesis" is explained on here.

See also

Notes

  1. "Multiple wavetable synthesis" ( Horner, Beauchamp & Haken 1993 ) developed by Michael McNabb and Wolfgang Palm in the late-1970s, is merely one of the efficient implementation techniques to realize dynamically changing waveforms, by using an array of single-cycle waveforms on a table-lookup synthesis. On this synthesis technique, the waveform can be animated in a similar manner as a flip book.

Related Research Articles

Digital synthesizer

A digital synthesizer is a synthesizer that uses digital signal processing (DSP) techniques to make musical sounds. This in contrast to older analog synthesizers, which produce music using analog electronics, and samplers, which play back digital recordings of acoustic, electric, or electronic instruments. Some digital synthesizers emulate analog synthesizers; others include sampling capability in addition to digital synthesis.

Physical modelling synthesis refers to sound synthesis methods in which the waveform of the sound to be generated is computed using a mathematical model, a set of equations and algorithms to simulate a physical source of sound, usually a musical instrument.

Karplus–Strong string synthesis is a method of physical modelling synthesis that loops a short waveform through a filtered delay line to simulate the sound of a hammered or plucked string or some types of percussion.

A software synthesizer, also known as a softsynth or software instrument, is a computer program or plug-in that generates digital audio, usually for music. Computer software that can create sounds or music is not new, but advances in processing speed now allow softsynths to accomplish the same tasks that previously required the dedicated hardware of a conventional synthesizer. Softsynths are usually cheaper and more portable than dedicated hardware, and easier to interface with other music software such as music sequencers.

Digital waveguide synthesis is the synthesis of audio using a digital waveguide. Digital waveguides are efficient computational models for physical media through which acoustic waves propagate. For this reason, digital waveguides constitute a major part of most modern physical modeling synthesizers.

Yamaha YM3812

The Yamaha YM3812, also known as the OPL2, is a sound chip created by Yamaha Corporation in 1985 and famous for its wide use in IBM PC-based sound cards such as the AdLib, Sound Blaster and Pro AudioSpectrum (8bit), as well as several arcade games by Nichibutsu, Toaplan and others.

Oscillator sync is a feature in some synthesizers with two or more VCOs, DCOs, or "virtual" oscillators. As one oscillator finishes a cycle, it resets the period of another oscillator, forcing the latter to have the same base frequency. This can produce a harmonically rich sound, the timbre of which can be altered by varying the synced oscillator's frequency. A synced oscillator that resets other oscillator(s) is called the master; the oscillators which it resets are called slaves. There are two common forms of oscillator sync which appear on synthesizers: Hard Sync and Soft Sync. According to Sound on Sound journalist Gordon Reid, oscillator sync is the least understood feature for many users of a synthesizer.

Direct digital synthesis

Direct digital synthesis (DDS) is a method employed by frequency synthesizers used for creating arbitrary waveforms from a single, fixed-frequency reference clock. DDS is used in applications such as signal generation, local oscillators in communication systems, function generators, mixers, modulators, sound synthesizers and as part of a digital phase-locked loop.

Korg DW-8000

The Korg DW-8000 synthesizer was an eight-voice polyphonic hybrid digital-analog synthesizer 61-note keyboard instrument released in 1985. By the time of its launch Korg had already begun a common trend in 1980s synthesizer design: using numerical codes to access or change parameters with the Korg Poly-61, which was widely regarded as the company's first 'knobless' synthesizer. This was a move away from the heavily laden, complex control panels of earlier designs.

Access Virus virtual analog synthesizer

The Access Virus is a virtual analog synthesizer made by the German company Access Music GmbH. It was first produced in 1997 and has since been upgraded frequently, with the company releasing new models about every two years. Early models include the Virus A, Virus B, and Virus C series, each available in various hardware configurations. In November 2005, the Virus TI series was released, including the 61-key Virus TI Keyboard and the 37-key Virus TI Polar. A small desktop model was released in February 2008 called the Virus TI Snow. A revision of the TI series called TI2 came out in March 2009, featuring faster digital signal processing (DSP), greater polyphony, more effects in the effect section and a slightly changed design. The Virus series also has come out with two software plugin versions: TDM for Pro Tools and VST for TC Electronic Powercore series. The term Access Virus can be used to refer to any one of these synthesizers.

Wavetable may refer to:

Korg Wavestation synthesizer first produced in the early 1990s

The Korg Wavestation is a vector synthesis synthesizer first produced in the early 1990s and later re-released as a software synthesizer in 2004. Its primary innovation was Wave Sequencing, a method of multi-timbral sound generation in which different PCM waveform data are played successively, resulting in continuously evolving sounds. The Wavestation's "Advanced Vector Synthesis" sound architecture resembled early vector synths such as the Sequential Circuits Prophet VS.

Linear Arithmetic synthesis, or LA synthesis, is a term invented by the Roland Corporation when they released their D-50 synthesizer in 1987.

Wolfgang Palm was a founder and owner of Palm Products GmbH (PPG), and the inventor and creator of various pioneering technical designs for analog and digital synthesizers. He is widely acknowledged as the father of digital synthesis, and as a trendsetter in the use of computer technology in the making of electronic music.

Synthesizer Electronic instrument capable of producing a wide range of sounds

A synthesizer or synthesiser is an electronic musical instrument that generates audio signals that may be converted to sound. Synthesizers may imitate traditional musical instruments such as piano, flute, vocals, or natural sounds such as ocean waves; or generate novel electronic timbres. They are often played with a musical keyboard, but they can be controlled via a variety of other devices, including music sequencers, instrument controllers, fingerboards, guitar synthesizers, wind controllers, and electronic drums. Synthesizers without built-in controllers are often called sound modules, and are controlled via USB, MIDI or CV/gate using a controller device, often a MIDI keyboard or other controller.

Korg DW-6000

The Korg DW-6000 is a six note polyphonic hybrid synthesizer with two single-cycle digital waveform oscillators and one analogue lowpass filter per voice. As basic material, eight digital wave cycle waveforms were available to the user through a system Korg called DWGS for Digital Waveform Generator System. The DWGS system can be thought of as an early sample playback system where only extremely short, single cycle waveforms are stored on four 256 Kilobit ROM chips, played back through the two digital oscillators and processed by relatively familiar subtractive synthesis facilities.

PPG Wave Audio Wavetable Synthesizer

The PPG Wave is a series of hybrid digital/analogue synthesizers built by the German company Palm Products GmbH from 1981 to 1987.

The Nord Wave is a 49-key polyphonic synthesiser developed by Clavia. It integrates the playback and manipulation of samples into a virtual analog and FM synth engine, which is a rare combination on keyboard synthesizers.

References

  1. Palm 2009.
  2. Andresen 1979.
  3. 1 2 Smith III, Julius O. "Viewpoints on the History of Digital Synthesis: Taxonomy of Digital Synthesis Techniques". Stanford, CA: Stanford University. Retrieved February 24, 2015.
  4. 1 2 McNabb, Michael. "Dreamsong: The Composition" (PDF). Computer Music Journal . 5 (4). Retrieved February 24, 2015.
  5. Bristow-Johnson 1996.
  6. https://web.archive.org/web/20120202001938/http://support.creative.com/kb/ShowArticle.aspx?sid=5800
  7. https://www.wikiaudio.org/wavetable-synthesis/
  8. Nelson, Jon Christopher (2000). "2. Understanding and Using Csound's GEN Routines". The Csound book. Cambridge, MA, USA: MIT Press. pp. 65–97. ISBN   0-262-52261-6.
    "Csound uses lookup tables for musical applications as diverse as wavetable synthesis, waveshaping, mapping MIDI note numbers and storing ordered pitch-class sets. These function tables (f-tables) contain everything from periodic waveforms to arbitrary polynomials and randomly generated values. The specific data are created with Csound's f-table generator subroutines, or GEN routines. ..."
  9. Roads 1996 , p.  87 , Introduction to Digital Sound Synthesis, "This chapter outlines the fundamental methods of digital sound production. Following a brief historical overview, we present the theory of table-lookup synthesisthe core of most synthesis algorithms. ..."
  10. Roads 1996 , p.  125 , Sampling Synthesis, "Pitch-shifting ... variation technique as used in 'wavetable-lookup synthesis described in chapter 3."
  11. Alles, H.G.; Giugno, Pepino di (November 1977). "A One-Card 64 Channel Digital Synthesizer". Computer Music Journal . 1 (4): 7–9. JSTOR   40731292. The samples in the wave shape table ...", "FIGURE 1 ... 16 K × 14 BIT WAVETABLE
  12. 1 2 3 Puckette, Miller (2002). "Max at seventeen" (reprint). Computer Music Journal . 26 (4): 31–43. (HTML version available) "For example, the wavetable oscillator used in Fig. 1 made its first appearance in Mathews's Music II (two, not eleven) in the late 1950s. Music II was only one in a long sequence of MUSIC N programs, but the idea of wavetable synthesis has had a pervasive influence throughout the computer music discipline."
  13. Boulanger, Richard; Lazzarini, Victor (eds.). "3.2.3 Table-Lookup Oscillators". The Audio Programming Book. Foreword by Max Mathews. MIT Press. p.  335 336. ISBN   978-0-262-28860-6.
    "In this section ... we will be introduce the table-lookup method for generating waveforms. This method is also called wavetable synthesis ... / Wavetable synthesis is a technique based on reading data that has been stored in blocks of contiguous computer-memory locations, called tables. This sound-synthesis technique was one of the very first software synthesis methods introduced in the MUSIC I-MUSIC V languages developed by Max Mathews at Bell Labs in the late 1950s and the early 1960s. ... / With table-lookup synthesis, it is sufficient to calculate only a single cycle of a waveform, and then store this small set of samples in the table where it serves as a template. ..."
    Note: on the above quotation, the authors paraphrased the section title "table-lookup oscillators" as follows: "table-lookup method", "wavetable synthesis", and "table-lookup synthesis".
  14. Hosken, Dan (2012). "The Oscillator". Music Technology and the Project Studio: Synthesis and Sampling. Routledge. p.  72 73. ISBN   978-1-136-64435-1.
    "The oscillator generates a cycle of some waveform the appropriate number of times per second for the desired fundamental frequency. This is referred to variously as fixed-waveform synthesis, table-lookup synthesis, or wavetable synthesis."
  15. Cullen, Michael. "Q. Can you explain the origins of wavetable, S&S and vector synthesis?". Sound on Sound (February 2006). SOS contributor Steve Howell replies: Wavetable synthesis is actually quite easy to understand. In the early days of synthesis, (analogue) oscillators provided a limited range of waveforms, such as sine, triangle, sawtooth and square/pulse, normally selected from a rotary switch. This gave the user a surprisingly wide range of basic sounds to play with, especially when different waveforms were combined in various ways.
  16. Karplus, Kevin; Strong, Alex (1983). "Digital Synthesis of Plucked-String and Drum Timbres" (PDF). Computer Music Journal (published Summer 1983). 7 (2): 45–55. doi:10.2307/3680062. JSTOR   3680062. Wavetable Synthesis: One standard synthesis technique is the wavetable synthesis algorithm. ... The wavetable-synthesis technique is very simple but rather dull musically, since it produces purely periodic tones. ... All the algorithms described in this paper produce the variation in sound by modifying the wavetable itself.
  17. 1 2 USapplication 5212334, Julius O. Smith, III,"Digital signal processing using closed waveguide networks",published 1993-05-18, assigned to Yamaha Corporation .
    (See also the Wikipedia article Digital waveguide synthesis: “The term "digital waveguide synthesis" was coined by Julius O. Smith III who helped develop it and eventually filed the patent. It represents an extension of the Karplus–Strong algorithm. Stanford University owns the patent rights for digital waveguide synthesis and signed an agreement in 1989 to develop the technology with Yamaha.”)
  18. Andresen, Uwe (Palm Productions) (1979). "A New Way in Sound Synthesis". 62nd Audio Engineering Society (AES) Convention (Brussels, Belgium).
  19. Sound on Sound & (February 2006), "However, in the late '70s, Wolfgang Palm used 'wavetable' digital oscillators in his innovative PPG Wave synths. Instead of having just three or four waveforms, a wavetable oscillator can have many more say, 64 because they are digitally created and stored in a 'look-up table' ... Now, if the waveforms are sensibly arranged, we can begin to create harmonic movement in the sound. ... you approach something not unlike a traditional filter sweep. ..."
  20. 1 2 Horner, Andrew; Beauchamp, James; Haken, Lippold (1993). "Methods for multiple wavetable synthesis of musical instrument tones" (PDF). J. Audio Eng. Soc. (published May 1993). 41 (5): 336–356. Multiple wavetable synthesis, the subject of this paper, is based on a sum of fixed waveforms or periodic basis functions with time-varying weights.
  21. Scheirer, Eric D. (MIT Media Lab); Ray, Lee (Joint E-Mu/Creative Technology Center) (1998). "Algorithmic and Wavetable Synthesis in the MPEG-4 Multimedia Standard". 105th Audio Engineering Society (AES) Convention (San Francisco, California). 2.2 Wavetable synthesis with SASBF: The SASBF wavetable-bank format had a somewhat complex history of development. The original specification was contributed by E-Mu Systems and was based on their “SoundFont” format [15]. After integration of this component in the MPEG-4 reference software was complete, the MIDI Manufacturers Association (MMA) approached MPEG requesting that MPEG-4 SASBF be compatible with their “Downloaded Sounds” format [13]. E-Mu agreed that this compatibility was desirable, and so a new format was negotiated and designed collaboratively by all parties.
  22. "1.4 Integrating AC '97 into the System". AC ‘97 Component Specification Revision 2.3 Rev 1.0 (PDF). Intel Corporation. April 2002. p.  11. Figure 2. AC ‘97 System Diagram: AC ‘97 Digital Controller / Optional hw acceleration / SRC*, mix*, 3D positional*, wavetable synth*
  23. Sound on Sound & (February 2006), "Other synths have employed wavetable synthesis in one guise or another since then and there are several software synths available today which incorporate wavetable synthesis capabilities."
    Note: on the above quotation, a specific wavetable synthesis developed by Wolfgang Palm, known as "multiple wavetable synthesis", is ambiguously referred as "wavetable synthesis".

Bibliography