Comparison Roland HP-702 vs Roland LX-705

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 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 add a reverb effect to the sound of the instrument.

Reverb is the repeated reflection and decay of sound. Most of all, this effect is noticeable in vast spaces with a pronounced echo — for example, large caves; however, in any environment, the coloring of the sound characteristic of such an environment is mainly due to reverberation. Thus, this function allows you to simulate music that sounds in different rooms — for example, to give the impression that the instrument is in the hall of a Gothic cathedral, or, conversely, in a small room with soft walls. However, it is also possible to use reverberation as a classic sound effect, which is not aimed at simulating the situation and only gives the sound a specific colour.

Additional features and sound customization options provided by the instrument in addition to those listed above. In this paragraph, usually, various original proprietary technologies and solutions are indicated; the specific meaning of these functions is best specified in the documentation for the tool.

The power of the native acoustics installed in the Digital Piano.

This indicator directly affects the maximum volume that the instrument is able to produce "on its own", without connecting external speakers. At the same time, it is worth noting that many manufacturers go to the trick and indicate in the characteristics not the rated power (rms power when operating at full volume), but the peak power, which is the highest power that the acoustics can deliver at short “ups” of volume. Peak power values can be quite impressive — in the tens and hundreds of watts — but these figures have a very indirect relation to the actual capabilities of the speakers. Therefore, before choosing, it is worth clarifying what kind of power is mentioned in the characteristics. To do this, it is not necessary to look for detailed data on the instrument, it is enough to compare the power of the speakers with the power consumption (see below): if the claimed power of the acoustics is greater than the power consumption of the entire instrument, then the manufacturer indicated exactly the peak value.

The number of bands provided in the Digital Piano's native acoustics.

In single-way acoustics, the speakers are responsible for reproducing the entire frequency range. Such systems are simple and inexpensive, but their amplitude-frequency response is far from perfect — most often they reproduce the mids well, but the bass turns out to be weak and unsaturated, the high frequencies are fuzzy and blurry. This is due to the fact that for each frequency there are separate requirements for the design of the speaker, and it is impossible to combine them in one speaker.

Thus, loudspeakers, including the built-in speakers of digital pianos, can be split into bands when the design provides for specialized speakers for a certain group of frequencies. The most advanced variant found in digital pianos is three-way, with separate sets of drivers for bass, mids, and treble. This allows you to achieve high-quality and reliable sound throughout the entire range, but complicates and increases the cost of the design. Therefore, three-way acoustics are rare, mainly in top-class instruments. But in mid-range instruments, two-way speakers are more often used (high frequencies on one set of speakers, medium plus low frequencies on the other).

The power consumed by the tool during normal operation.

The cost of electricity, as well as connection requirements, depend on this indicator. At the same time, we note that digital pianos require relatively little energy — even in the most powerful and advanced models, consumption usually does not exceed 60 watts. So in fact, power consumption data is required mainly for specific cases — for example, to calculate the total load when connecting a tool to an autonomous generator along with other devices. In addition, this information may be useful when assessing the power of the built-in speaker, for more information, see "Built-in acoustics".