Octave shift
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.
Number of bands
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).