Frequency modulation synthesis

The (instantaneous) frequency of an oscillator is altered in accordance with the amplitude of a modulating signal.

As the amount of frequency modulation increases, the sound grows progressively complex.

FM synthesis using analog oscillators may result in pitch instability.

[2] However, FM synthesis can also be implemented digitally, which is more stable and became standard practice.

Digital FM synthesis (equivalent to phase modulation using the time integration of instantaneous frequency) was the basis of several musical instruments beginning as early as 1974.

[6] FM synthesis also became the usual setting for games and software up until the mid-nineties.

OPNB was notably used in SNK's Neo Geo arcade (MVS) and home console (AES) machines, as well as being used as the main basic sound generator in Taito's arcade boards (with a variant of the OPNB being used in the Taito Z System board).

FM synthesis was also used on a wide range of mobile phones in the 2000s to play ringtones and other sounds, using the Yamaha SMAF format.

Don Buchla implemented FM on his instruments in the mid-1960s, prior to Chowning's patent.

By the mid-20th century, frequency modulation (FM), a means of carrying sound, had been understood for decades and was being used to broadcast radio transmissions.

FM synthesis was developed since 1967 at Stanford University, California, by John Chowning, through his exploration of digital synthesis and spatialization, inspired by the new possibilities of digital sound as described by Max Mathews[citation needed].

His algorithm[citation needed] was licensed to Japanese company Yamaha in 1973.

[3] The implementation commercialized by Yamaha (US Patent 4018121 Apr 1977[9] or U.S. Patent 4,018,121[10]) is actually based on phase modulation[citation needed], but the results end up being equivalent mathematically as both are essentially a special case of quadrature amplitude modulation[citation needed].

[11] Yamaha's engineers began adapting Chowning's algorithm for use in a commercial digital synthesizer, adding improvements such as the "key scaling" method to avoid the introduction of distortion that normally occurred in analog systems during frequency modulation[citation needed], though it would take several years before Yamaha released their FM digital synthesizers.

[12] In the 1970s, Yamaha were granted a number of patents, under the company's former name "Nippon Gakki Seizo Kabushiki Kaisha", evolving Chowning's work.

Several other models by Yamaha provided variations and evolutions of FM synthesis during that decade.

It had a similar (but slightly differently derived) sound quality to the DX series.

New hardware synths specifically marketed for their FM capabilities disappeared from the market after the release of FS1R in 1999, however, well-developed FM synthesis options are a feature of Nord Lead synths manufactured by Clavia, the Alesis Fusion range, the Korg Oasys and Kronos and the Modor NF-1.

Various other synthesizers offer limited FM abilities to supplement their main engines.

Formants can be used to model resonating body instrument sounds like the cello, violin, acoustic guitar, bassoon, English horn, or human voice.

[19] It was then followed by the more affordable Yamaha MODX in 2018, with 64-voice, 8 operators FM-X architecture in addition to a 128-voice sample-based engine.

[20] The MODX+ released in 2022 increased the number of voices of the FM-X engine to 128, the same as with the Montage.

[17] [citation needed] Combining sets of 8 FM operators with multi-spectral wave forms was first introduced in the FS1R, released in 1999 by Yamaha.