Polyphony
The polyphony supported by a synthesizer, in other words, is the number of “voices” (tone generators) that can simultaneously sound on it.
This parameter is often described as the number of notes that can be played simultaneously on the keyboard. However, this is not entirely true due to the fact that in many timbres one note can activate several tone generators. As a result, for example, to play a chord of 3 notes in a timbre with 4 tone generators per note, polyphony of at least 3 * 4=12 voices is required. In addition, Auto Accompaniment and Preset Songs (see related sections) also use tone generators, requiring even more voices to work effectively with these features.
The minimum value for a more or less functional modern synthesizer is polyphony for 32 voices — and even then such an instrument can be used mainly for initial training and simple melodies. For a more solid application, it is desirable to have at least 50 – 60 voices, and in professional models (in particular, workstations where you have to deal with several audio tracks at once), there are models with polyphony for 150 tone generators or more.
In general, a more advanced synthesizer is likely to have more extensive polyphony, however, it is only possible to evaluate the class of an instrument by this parameter very approximately — instruments with the same number of voices can differ greatly in level. The only exception to this rule are children's synthesizers (see "T...ype"), which support up to 20 voices.
Built-in timbres
The number of built-in sounds provided in the synthesizer.
The number of timbres is often described as the number of instruments that a given model can imitate. However, this is not entirely true — rather, this parameter can be called "the number of instruments and sound effects." For example, the same instrument — an electric guitar — with different "gadgets" (distortion, overdrive) will sound differently, and in the synthesizer each such gadget will be considered a separate timbre. The “drums” timbre usually combines different types of drums and other percussion instruments — in other words, it allows you to portray both the “bass drum” and the cymbals without switching settings, just by pressing the desired keys. And some timbres may not have analogues among real instruments at all.
The more built-in timbres, the more extensive the possibilities of the synthesizer, the more diverse the sounds that can be extracted from it. At the same time, in high-end models like workstations (see "Type"), this number can reach 1000 or even more.
Accompaniment styles
The number of auto accompaniment styles (see above) originally provided in the synthesizer, in other words, the number of accompaniment options available to the user.
The more extensive this set, the higher the probability of finding among these melodies suitable options for a particular case. At the same time, the abundance of styles in itself is not yet a 100% guarantee that among them there will be a suitable one, especially since different synthesizer models can differ markedly in a specific set of melodies. So the list does not hurt to clarify before buying. Also note that the situation can be corrected by user styles (see below) — many synthesizers with auto accompaniment support them.
Vocoder
In a very simplified way, a
vocoder can be described as a device that allows you to combine the sound of a voice with the sound of another instrument. In more detail, the vocoder allows you to transfer the properties of the voice to the signal of another timbre; in this case, the voice plays the role of a modulator, and the other timbre plays the role of a carrier. Due to this, various interesting effects can be achieved: give a live voice the intonation of a “robot”, create the effect of a “speaking” instrument (guitar, piano, etc.), supplement the performer’s own voice with a synthesized “choir”, etc. Technically, even another instrument can be used instead of a voice as a modulating signal — for example, you can combine drums with a guitar or a piano with a trumpet. However, in fact, it is the voice coming from an external microphone that is most often used as a modulator (although it would not hurt to clarify the specific functionality of this module separately).
Microphone
The number of microphone inputs provided in the design of the synthesizer.
Microphones are mainly used for working with voice or recording sound samples (see "Sampling"). At the same time, in high-end models like professional instruments and workstations (see "Type"), there may be more than one microphone input — for example, for simultaneous recording of two vocalists, recording a sample from several sources on the fly, or recording stereo sound from a pair of microphones . At the same time, such tasks are quite specific and rare, and for most modern synthesizers one microphone is enough (if there is such an input at all).
Connectable pedals
The number of pedals that can be connected to the synthesizer at the same time.
Pedals are additional controls that expand the capabilities of the instrument. One of the most famous pedal functions, familiar to many from classical pianos and grand pianos, is “sustain”, where the sound continues to sound after the key is released, slowly fading out. However, the matter is not limited to this, the purpose of the pedals can be very diverse: enabling or disabling additional effects, switching between octaves or keys, etc. At the same time, in some synthesizers, mostly inexpensive, the assignment of the pedals is fixed, in others it can be reconfigured to fit your goals.
For most instruments, one pedal is sufficient, but high-end models such as workstations (see "Type") may support multiple connections.
Linear outputs
The number of line outputs provided in the design of the synthesizer.
The line output is used to transmit the sound produced by the synthesizer to external devices. At the same time, unlike the MIDI output, a “ready” sound is transmitted through such a connector — an analogue line-level audio signal that can be connected to another audio device — for example, to a power amplifier or active speakers for playback, to a computer or mixing console for recording, etc. Keep in mind that the line outputs can use different types of connectors — for example, 3.5 mm mini-Jack or 6.35 mm Jack; Specifically, these connectors are described in more detail in the “Inputs” section, but the matter is not limited to them.
Multiple analogue inputs make it possible to connect the synthesizer to several external audio devices at the same time — for example, to an amplifier for playback and a recorder for recording.
