Number of keys
The greater the number of keys — the wider the range of the instrument, the lower and higher notes you can take on it right during the game, without resorting to tricks like octave shift (see below). By comparison, a full size piano keyboard has 88 keys. However, in synthesizers, such an amount is rare, because. the instrument would have turned out to be too bulky and expensive, and not every musician, even a professional one, needs such an extensive range. Thus, 88-key keyboards are used primarily in high-end workstations (see "Type"). For ordinary synthesizers, the standard is
49, 61 or 76 keys ( there are also options for
73 keys) — this is usually quite enough (while the "golden mean" option is considered to be
61 keys). And small children's models can have 32 keys.
Sensitivity adjustment
Ability
to change the sensitivity of active mechanics (see above) in the synthesizer.
This function allows you to adjust the intensity of the key's response to pressing. Simply put, the higher the sensitivity, the louder and sharper the sound will be, with the same pressing force. This allows you to change the characteristics of the instrument's sound.
Also in synthesizers with this function, it is often possible to completely turn off the active mechanics and play on a “passive” keyboard. This can be useful for making certain voices, such as harpsichord or organ, sound realistic.
Rigidity
—
Unweighted. Keys with a very low pressing force, literally "failing" under the fingers. This option is well suited for inexpensive synthesizers with passive mechanics (see above), but is rarely used in active models — a small resistance force makes it difficult to choose the optimal pressing force.
— Semi-
weighted. Medium-strength keys, not up to the hardness of a full-fledged piano, but showing noticeably more resistance than unweighted ones. This variant is most popular among instruments with active mechanics (see above) — the force on the keys provides adequate feedback and at the same time playing such an instrument does not cause any special difficulties even for those who previously dealt only with unweighted keyboards.
—
Weighted. Keys with high actuation force, comparable to that of a classical piano. Used only in professional
hammer action instruments (see above) — high rigidity is a must for such mechanics (more precisely, for the response that it must provide).
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.
User timbres
The number of memory slots for user tones provided in the synthesizer.
For Voices in general, see “Preset Voices” above. User timbres are sound settings that were not originally provided in the synthesizer's memory and are created by the user according to their preferences. This feature is indispensable in cases where the built-in set of timbres does not contain the necessary options. However, the capabilities of the User Voices may vary from model to model. So, one instrument only allows you to edit and supplement existing timbres (for example, add a “wah-wah” effect to a bass guitar and save such a bunch as a user setting), another makes it possible to set the sound parameters almost manually, and the third even allows you to load timbres through USB (see below).
The more user timbres in the synthesizer, the more personal “instruments” you can register in its memory.
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.
Custom styles
The number of user auto accompaniment styles supported by the synthesizer, in other words, the number of additional styles that can be stored in memory in addition to the built-in ones. Note that styles can have different volumes (depending on the number of notes used), so this parameter often turns out to be not exact, but only an average-approximate one.
Modern synthesizers may have a fairly extensive set of built-in auto accompaniment styles (see above), but even the richest set may not contain the desired melody. Thus, many models allow you to supplement the standard list with custom melodies. The addition methods themselves can be different: in some models, these melodies need to be downloaded from external media, in others they can even be composed manually. Nevertheless, the presence of user styles allows you to expand the range of auto accompaniment melodies, moreover, at the request of the user himself.
Tempo change
The range in which you can change the tempo of the programme played by the synthesizer — auto accompaniment, lesson tune (see above), metronome (see below), recorded sample, etc.
Pace is measured in beats per minute. Changing it allows you to adjust the speed of the synthesizer to the specifics of the situation — for example, slightly slow down the tutorial if it is too hard to master at the initial pace. The wider the range of tempo adjustment, the more options the musician has to choose from, especially in the area of very slow and very fast tempos.
Note that the traditional range of musical tempos covers values from 40 beats / min (“grave”, “very slowly”) to 208 beats / min (“prestissimo”, “very fast”), however, in synthesizers it can be more extensive — for example, 30 – 255 bpm.