Built-in timbres
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").
Reverberation
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.
More features
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.
Connectable pedals
The largest number of pedals that can be connected to the Digital Piano at the same time.
Pedals are an indispensable element of equipping a traditional piano, respectively, they are also necessary for electronic analogues of this instrument. However, in stationary devices (see "Body") the pedals are made built-in (see above), so this option is found only in portable models. Also note that if a stationary digital piano has 3 pedals as standard — like in a real piano — then portable digital pianos often have fewer. This is due to the fact that a full set of three pedals is rarely required in fact, and in many cases just one is enough (especially since many instruments allow you to reconfigure its functions).
In general, it makes sense to specifically buy an instrument with three connected pedals mainly for demanding professional musicians who value the full functionality of the pedals (or the ability to tie an extended set of functions to the foot control). In other cases, this parameter is not particularly important.