Physical modelling 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.
General methodology
Modelling attempts to replicate laws of physics that govern sound production, and will typically have several parameters, some of which are constants that describe the physical materials and dimensions of the instrument, while others are time-dependent functions describing the player's inhe slip-stick behavior of the bow against the string, the width of the bow, the resonance and damping behavior of the strings, the transfer of string vibrations through the bridge, and finally, the resonance of the soundboard in response to those vibrations.
Technologies associated with physical modelling
Examples of physical modelling synthesis:
- Karplus-Strong string synthesis
- Digital waveguide synthesis
- Mass-Interaction physical networks
- Formant synthesis
- Articulatory synthesis
Hardware synthesizers
- Korg OASYS and Korg Kronos – STR-1 Plucked string
- Korg OASYS PCI
- Korg Prophecy
- Korg SOLO-TRI (an expansion board for the Trinity with the synth engine of the Prophecy)
- Korg Z1
- Korg MOSS-TRI (a expansion board for the Trinity with the synth engine of the Z1) and EXB-MOSS (a multi timbral expansion board for the Triton and the KARMA workstation with the synth engine of the Z1)
- Yamaha VL1, VP1 and VL7
- Yamaha VL70m, PLG-100VL and 150VL (VL70m in the form of a plug-in card that can be installed into any of several Yamaha keyboards, tone modules, and the SW1000XG high-end PC midi sound card)
- Yamaha EX5, EX5R
- Technics WSA1/WSA1R
- Clavia Nord Modular G2
- Alesis Fusion
- Roland V-Piano
- Pianoid
- Physis Unico
- Physis Piano (made in Italy, with a full touch controlled user interface)
- Hartmann Neuron and Neuron VS
While not purely a hardware synth, the Yamaha DS-XG sound cards included hardware-assisted software VL physical modelling along with the Yamaha XG, wave audio, and 3D gaming sound capabilities of the chipset. But as they were not fully compatible with the AC-97 and later AC-98 standards, these chipsets have not been manufactured in nearly a decade.
The WSA1 (and its rackmounted counterpart WSA1R) was Technics' first and only try at high-end synthesizers. It featured 64 voices of polyphony with a combination of sample playback (for initial transients) and DSP acoustic modelling. Launched in 1995 with an MSRP of $5,000 (USD), the WSA1 was not a commercial success; only about 600 keyboards and 300 rack models were ever made, and most were sold at highly discounted prices.
Various Roland synthesizer models (V-Synth, V-Combo, XV-5080, Fantom, etc.) use COSM ("Composite Object Sound Modeling") physical modeling techniques to replicate guitars, brass and other instruments. COSM has been superseded by "SuperNatural", also based on physical modeling techniques. Introduced first in 2008 as part of the ARX expansion boards for Fantom hardware synthesizers, "SuperNatural" modeling is used in Roland's V-Drums (TD-30, TD-15, TD-11), V-Accordions (FR-7, FR-8) and various synth models (Jupiter 80, Integra 7, FA-08, JD-Xi, etc.) Later this has been expanded to ACB ("Analogue Circuit Behaviour"), using similar physical modeling techniques as before, which were incorporated into Roland's latest line of AIRA hardware synthesizer products (TB-3, System-1, System-1m, System-8), as well as their 'Boutique' line of hardware modules (JP08, JX03, JU06). While the Roland ESC2 chip inside the TD-30 and Integra-7 sound modules were marketed as "SuperNatural" modelling, the same ESC2 chip inside latest Roland "AIRA" and Boutique Products (System-1, System-1m, System-8, SH-01A, D-05, etc) was marketed as "ACB" or DCB (“Digital Circuit Behaviour”, in case of the D-05) modelling technology.
Software synthesizers
- SWAM-S Bowed Strings by Audio Modeling (based on the Digital Waveguide Synthesis and on the SWAM technology)
- Pianoteq by Modartt (Various Pianos based on physical modelling synthesis)
- MODO by IK Multimedia (Electric basses based on physical modelling synthesis)
- Arché by Expressive E (Bowed string instruments based on physical modelling synthesis)
- Iron Axe by Xhun Audio (Electric guitar based on physical modelling synthesis)
- Sculpture by Apple, built into their Logic Pro X and Mainstage programs (wood, nylon, steel, and glass fundamental models, capable of a huge variety of sounds)
- Madrona Labs Kaivo (Physical Modeling and granular synthesis)
References
- Hiller, L.; Ruiz, P. (1971). "Synthesizing Musical Sounds by Solving the Wave Equation for Vibrating Objects". Journal of the Audio Engineering Society.
- Karplus, K.; Strong, A. (1983). "Digital synthesis of plucked string and drum timbres". Computer Music Journal. 7 (2). Computer Music Journal, Vol. 7, No. 2: 43–55. doi:10.2307/3680062. JSTOR 3680062.
- Julius O. Smith III (December 2010). Physical Audio Signal Processing.
- Cadoz, C.; Luciani A; Florens JL (1993). "CORDIS-ANIMA : a Modeling and Simulation System for Sound and Image Synthesis: The General Formalism". Computer Music Journal. 17/1 (1). Computer Music Journal, MIT Press 1993, Vol. 17, No. 1.
Footnotes
Further reading
- "The next generation, part 1". Future Music. No. 32. Future Publishing. June 1995. p. 80. ISSN 0967-0378. OCLC 1032779031.