synthesizer
A sound synthesizer (often abbreviated as "synthesizer" or "synth") is an electronic instrument capable of producing a wide range of sounds. Synthesizers may either imitate other instruments ("imitative synthesis") or generate new timbres. They can be played (controlled) via a variety of different input devices (including keyboards, music sequencers and instrument controllers). Synthesizers generate electric signals (waveforms), and can finally be converted to sound through loudspeakers or headphones.
Synthesizers use a number of different technologies or programmed algorithms to generate signal, each with their own strengths and weaknesses. Among the most popular waveform synthesis techniques are subtractive synthesis, additive synthesis, wavetable synthesis, frequency modulation synthesis, phase distortion synthesis, physical modeling synthesis and sample-based synthesis. Also other sound synthesis methods including subharmonic synthesis used on mixture trautonium, granular synthesis resulting Soundscape or Cloud, are rarely used.
Synthesizers are often controlled with a piano-style keyboard. Other forms of controllers resemble fingerboards, guitars (guitar synthesizer), violins, wind instruments (wind controller), drums and percussions (electronic drum), etc. Synthesizers without built-in controllers are often called sound modules, and are controlled via MIDI or CV/Gate methods.
Additive synthesis builds sounds by adding together waveforms (which are usually harmonically related). An early analog example of an additive synthesizer is the Teleharmonium and Hammond organ. To implement real-time additive synthesis, wavetable synthesis is useful for reducing required hardware/processing power, and is commonly used in low-end MIDI instruments (such as educational keyboards) and low-end sound cards. |
Subtractive Synthesis is still utilized on various synths, including virtual analog synth.
Subtractive synthesis is based on filtering harmonically rich waveforms. Due to its simplicity, it is the basis of early synthesizers such as the Moog synthesizer. Subtractive synthesizers use a simple acoustic model that assumes an instrument can be approximated by a simple signal generator (producing sawtooth waves, square waves, etc.) followed by a filter. The combination of simple modulation routings (such as pulse width modulation and oscillator sync), along with the physically unrealistic lowpass filters, is responsible for the "classic synthesizer" sound commonly associated with "analog synthesis" and often mistakenly used when referring to software synthesizers using subtractive synthesis.
FM Synthesis was hugely successful in earliest digital synthesizers.
FM synthesis (frequency modulation synthesis) is a process that usually involves the use of at least two signal generators (sine-wave oscillators, commonly referred to as "operators" in FM-only synthesizers) to create and modify a voice. Often, this is done through the analog or digital generation of a signal that modulates the tonal and amplitude characteristics of a base carrier signal. FM synthesis was pioneered by John Chowning, who patented the idea and sold it to Yamaha. Unlike the exponential relationship between voltage-in-to-frequency-out and multiple waveforms in classical 1-volt-per-octave synthesizer oscillators, Chowning-style FM synthesis uses a linear voltage-in-to-frequency-out relationship and sine-wave oscillators. The resulting complex waveform may have many component frequencies, and there is no requirement that they all bear a harmonic relationship. Sophisticated FM synths such as the Yamaha DX-7 series can have 6 operators per voice; some synths with FM can also often use filters and variable amplifier types to alter the signal's characteristics into a sonic voice that either roughly imitates acoustic instruments or creates sounds that are unique. FM synthesis is especially valuable for metallic or clangorous noises such as bells, cymbals, or other percussion.
Phase distortion synthesis is a method implemented on Casio CZ synthesizers. It is quite similar to FM synthesis but avoids infringing on the Chowning FM patent. Also it should be categorized to modulation synthesis along with FM synthesis, and also to distortion synthesis along with waveshaping synthesis, and discrete summation formulas.
Granular synthesis is a type of synthesis based on manipulating very small sample slices. |
Physical modelling synthesis is often implemented as software synthesizers.
Physical modelling synthesis is the synthesis of sound by using a set of equations and algorithms to simulate a real instrument, or some other physical source of sound. This involves taking up models of components of musical objects and creating systems that define action, filters, envelopes and other parameters over time. The definition of such instruments is virtually limitless, as one can combine any given models available with any amount of sources of modulation in terms of pitch, frequency and contour. For example, the model of a violin with characteristics of a pedal steel guitar and perhaps the action of piano hammer. When an initial set of parameters is run through the physical simulation, the simulated sound is generated. Although physical modeling was not a new concept in acoustics and synthesis, it was not until the development of the Karplus-Strong algorithm and the increase in DSP power in the late 1980s that commercial implementations became feasible. Physical modeling on computers gets better and faster with higher processing.
Analysis/resynthesis is typically known as vocoder.
Sample-based synthesis is one of the most popular family of synthesis on today.
Sample-based synthesis One of the easiest synthesis systems is to record a real instrument as a digitized waveform, and then play back its recordings at different speeds to produce different tones. This is the technique used in "sampling". Most samplers designate a part of the sample for each component of the ADSR envelope, and then repeat that section while changing the volume for that segment of the envelope. This lets the sampler have a persuasively different envelope using the same note. See also Wavetable synthesis, Vector synthesis, etc.
Analysis/resynthesis is a form of synthesis that uses a series of bandpass filters or Fourier transforms to analyze the harmonic content of a sound. The resulting analysis data is then used in a second stage to resynthesize the sound using a band of oscillators. The vocoder, linear predictive coding, and some forms of speech synthesis are based on analysis/re-synthesis.
Physical modelling synthesis is the synthesis of sound by using a set of equations and algorithms to simulate a real instrument, or some other physical source of sound. This involves taking up models of components of musical objects and creating systems that define action, filters, envelopes and other parameters over time. The definition of such instruments is virtually limitless, as one can combine any given models available with any amount of sources of modulation in terms of pitch, frequency and contour. For example, the model of a violin with characteristics of a pedal steel guitar and perhaps the action of piano hammer. When an initial set of parameters is run through the physical simulation, the simulated sound is generated. Although physical modeling was not a new concept in acoustics and synthesis, it was not until the development of the Karplus-Strong algorithm and the increase in DSP power in the late 1980s that commercial implementations became feasible. Physical modeling on computers gets better and faster with higher processing.
Analysis/resynthesis is typically known as vocoder.
Sample-based synthesis is one of the most popular family of synthesis on today.
Sample-based synthesis One of the easiest synthesis systems is to record a real instrument as a digitized waveform, and then play back its recordings at different speeds to produce different tones. This is the technique used in "sampling". Most samplers designate a part of the sample for each component of the ADSR envelope, and then repeat that section while changing the volume for that segment of the envelope. This lets the sampler have a persuasively different envelope using the same note. See also Wavetable synthesis, Vector synthesis, etc.
Analysis/resynthesis is a form of synthesis that uses a series of bandpass filters or Fourier transforms to analyze the harmonic content of a sound. The resulting analysis data is then used in a second stage to resynthesize the sound using a band of oscillators. The vocoder, linear predictive coding, and some forms of speech synthesis are based on analysis/re-synthesis.
Synth Lead
]In popular music, a synth lead is generally used for playing the main melody of a song, but it is also often used for creating rhythmic or bass effects. Although most commonly heard in electronic dance music, synth leads have been used extensively in hip-hop since the 1980s and rock songs since the 1970s. Most modern music relies heavily on the synth lead to provide a musical hook to sustain the listener's interest throughout an entire song. Heavy use of synth lead is used for example by Lil Jon in "Snap Yo Fingas" and Usher in "Yeah!" as representative of the Crunk music genre. |
Synth Pad
A synth pad is a sustained chord or tone generated by a synthesizer, often employed for background harmony and atmosphere in much the same fashion that a string section is often used in acoustic music. Typically, a synth pad plays many whole or half notes, sometimes holding the same note while a lead voice sings or plays an entire musical phrase. Often, the sounds used for synth pads have a vaguely organ, string, or vocal timbre. Much popular music in the 1980s employed synth pads, this being the time of polyphonic synthesizers, as did the then-new styles of smooth jazz and New Age music. One of many well-known songs from the era to incorporate a synth pad is "West End Girls" by the Pet Shop Boys, who were noted users of the technique. The main feature of a synth pad is very long attack and decay time with extended sustains. In some instances pulse-width modulation (PWM) using a square wave oscillator can be added to create a "vibrating" sound. |
Synth Bass
The bass synthesizer (or "bass synth") is used to create sounds in the bass range, from simulations of the electric bass or double bass to distorted, buzz-saw-like artificial bass sounds, by generating and combining signals of different frequencies. Bass synth patches may incorporate a range of sounds and tones, including wavetable-style, analog, and FM-style bass sounds, delay effects, distortion effects, envelope filters. A modern digital synthesizer uses a frequency synthesizer microprocessor component to generate signals of different frequencies. While most bass synths are controlled by electronic keyboards or pedalboards, some performers use an electric bass with MIDI pickups to trigger a bass synthesizer. |
Arpeggiator
An arpeggiator is a feature available on several synthesizers that automatically steps through a sequence of notes based on an input chord, thus creating an arpeggio. The notes can often be transmitted to a MIDI sequencer for recording and further editing. An arpeggiator may have controls speed, range, and order in which the notes play; upwards, downwards, or in a random order. More advanced arpeggiators allow the user to step through a pre-programmed complex sequence of notes, or play several arpeggios at once. Some allow a pattern sustained after releasing keys: in this way, sequence of arpeggio patterns may be built up over time by pressing several keys one after the other. Arpeggiators are also commonly found in software sequencers. Some arpeggiators/sequencers expand features into a full phrase sequencer, which allows the user to trigger complex, multi-track blocks of sequenced data from a keyboard or input device, typically synchronized with the tempo of the master clock.
An arpeggiator is a feature available on several synthesizers that automatically steps through a sequence of notes based on an input chord, thus creating an arpeggio. The notes can often be transmitted to a MIDI sequencer for recording and further editing. An arpeggiator may have controls speed, range, and order in which the notes play; upwards, downwards, or in a random order. More advanced arpeggiators allow the user to step through a pre-programmed complex sequence of notes, or play several arpeggios at once. Some allow a pattern sustained after releasing keys: in this way, sequence of arpeggio patterns may be built up over time by pressing several keys one after the other. Arpeggiators are also commonly found in software sequencers. Some arpeggiators/sequencers expand features into a full phrase sequencer, which allows the user to trigger complex, multi-track blocks of sequenced data from a keyboard or input device, typically synchronized with the tempo of the master clock.
http://en.wikipedia.org/wiki/Synthesizer