Comparison Kurzweil M90 vs Casio Privia PX-770

The ability to adjust the sensitivity of the digital piano keyboard.

The sensitivity level determines the volume and sharpness of the sound that the instrument will produce at a certain force and speed of pressing the key. High sensitivity allows you to achieve sharp, expressive sound with significant volume differences, low — relatively quiet, soft and smoothed. And some instruments even provide "zero" sensitivity — when all keys sound with the same volume and dynamics, regardless of the pressing force. This can be useful, for example, to imitate the sound of certain instruments (such as the harpsichord).

The number of voices supported by the digital piano — more precisely, the maximum number of voices that the instrument can play at the same time.

This parameter should not be confused with the number of notes that can be played simultaneously on the keyboard. The fact is that in many timbres, several voices (tone generators) are used for each note at once — this is the only way to achieve a more or less reliable sound. Thus, the required number of voices can be many times higher than the number of notes — for example, the simplest chord of 3 notes may require 9 or even 12 voices. In addition, tone generators are used to play auto accompaniment parts and built-in songs (see below), and here the number of voices can already be measured in tens.

In light of all this, polyphony of less than 90 voices is typical mainly for relatively simple and inexpensive instruments that are not designed for complex tasks. The smallest number found in modern digital pianos is 32 voices. It is desirable for a more or less solid instrument to have at least 96 voices, and in top models this figure can reach 256.

The number of built-in sounds provided by the Digital Piano.

Despite the name, digital pianos are extremely rarely designed to imitate the sound of only a piano — the electronic hardware allows them to provide other timbres of sound. In addition, even the piano has its own varieties — for example, among the grand pianos there are 6 main classes, from large concert to miniature. So the built-in sounds can cover different kinds of pianos, as well as other instruments and sound effects.

The abundance and variety of timbres in digital pianos as a whole is not as great as in synthesizers, however, in this category there are very “charged” models, with a hundred timbres or more (in the most multifunctional, this number can exceed 900). However, it is worth specifically looking for a “multi-instrumental” model if you do not intend to be limited to the sound of the piano and would like to have more freedom of choice. It is worth remembering that a specific set of timbres can be different.

If the instrument is bought exclusively as a piano, then here, on the contrary, it is worth paying attention primarily to solutions with a small number of timbres. Such models are not only cheaper than "universals" — they can also sound better (due to the fact that there are few timbres and the manufacturer can carefully approach the sound quality of each built-in "instrument").

The presence of a training mode in the digital piano.

As the name suggests, this mode is designed to teach the game. At the same time, usually, it provides different levels of difficulty — from the most basic, for those who are just starting to master the "keys", to the advanced one, which allows you to train your technique and improve your existing performance skills. However, anyway, the principle of learning is the same: the tool independently tells the student which keys to press at one time or another. Such hints can be in the form of a backlight (see above) or as a graphic on the display. Such a method is doubtful from the point of view of classical academic learning, however, it is undoubtedly more convenient and faster than reading musical notation. Moreover, the instrument can also play the role of an examiner — launch prompts at the original tempo of the melody and check how accurately the student hits the notes.

Also note that the learning mode requires the obligatory presence of a metronome (see below).

The range over which the tempo of the sound played by the instrument can change. It can be either a built-in melody or a part recorded on a sequencer, or an auto accompaniment, a tutorial or a metronome. For more information on all of these features, see the corresponding glossary entries. Here we note that a change in tempo is often required in fact — for example, to speed up an initially "sluggish" accompaniment or slow down a training programme that is difficult to master at the original tempo.

Tempo is traditionally indicated in beats per minute. The classical, "academic" range covers options from 40 bpm ("grave", "very slow") to 208 bpm ("prestissimo", "very fast"), however, in modern digital pianos, the working range of tempos is often significantly wider.

The presence of an octave shift function in the digital piano.

This function makes it possible to "shift" the sound by a certain number of octaves up or down — for example, in such a way that the bass register sounds on the keys of the first octave, or vice versa, the first octave "slid" lower, into the bass, and notes of the second sounded in its place or even the third octave.

This feature significantly expands the range of the instrument, allowing you to play notes that were not originally covered by the keyboard. This is especially important for instruments with 61 or 73 keys (see "Number of Keys"), but octave shifting is not uncommon in full-sized 88-key models — it can be useful when splitting the keyboard (see above), when available for each hand the range is noticeably reduced, and the batch can be very low or very high. However, there are other options for using transfer — for example, so that when playing an updated version of the melody, you do not have to move from the usual octaves.

The ability to change the brightness of the sound of certain timbres or tracks.

Brightness determines the overall colour of the sound — from soft, smoothed to sonorous, sharp. This feature allows the player to adjust this coloration to their preference, and thus further expands the possibilities for customizing the sound of the instrument.

The ability to fine-tune the digital piano for specific frequencies.

The essence of this function is generally similar to transposition — a slight shift of each note in frequency up or down. However, with fine tuning, the shift does not occur in steps (by an integer number of semitones), but very slowly and smoothly — by a certain number of hertz or even tenths of a hertz relative to the base scale. The base scale is often called "440 Hz" — this is the standard frequency of the "la" note of the first octave, according to which the rest of the scale is tuned. For a musician, fine tuning usually looks like an opportunity to set a different key frequency value — for example, 438 Hz or 441.2 Hz.

This feature can be useful for tuning the digital piano to another instrument whose frequencies change smoothly, such as a guitar. In many situations, it is easier to change the frequency settings in a digital device than to twist the strings or otherwise fiddle with complex tuning.

— USB to host (type B). Connector for connecting a digital piano to a computer using the USB standard; in this case, the instrument plays the role of a peripheral device. The possibilities of such a connection can be different: recording live music, updating firmware, voices and auto accompaniment styles, using the digital piano as an external MIDI keyboard, fine-tuning the instrument and troubleshooting, etc.; specific functionality varies from model to model.

— MIDI out. An output that allows you to broadcast MIDI signals (MIDI events) from the Digital Piano to external devices. A MIDI signal is, in fact, a "preparation" of sound: a signal generated when a key is pressed and containing information about the note number, duration, and force of pressing. Based on this signal, the electronics of the instrument (or other device) generates the sound of a certain timbre. The MIDI output can be useful for connecting a digital piano to, for example, an external sequencer for recording, or to a synthesizer for playback in a tone that is not in the piano itself.

— MIDI thru. Output used for switching MIDI signals. The description of such signals is given above, but here we note that the MIDI thru output duplicates the signals received at the MIDI input of the digital piano. This function can be useful in some specific cases — for example, connecting several electr...onic instruments together.