In general, the sounds produced by a digital piano are based on sampling, by which real piano sound samples are stored in ROM. The samples stored in digital pianos are usually of very precision recording and made using high-quality pianos, expensive microphones, and high-quality preamps in a professional recording studio. ROM may include multiple samples for the same keystroke, attempting to reproduce diversity observed on the real piano, but the number of these recorded alternatives is limited.
Macaque monkeys drum objects in a rhythmic way to show social dominance and this has been shown to be processed in a similar way in their brains to vocalizations suggesting an evolutionary origin to drumming as part of social communication. Other primates make drumming sounds by chest beating or hand clapping, and rodents such as kangaroo rats also make similar sounds using their paws on the ground.
Since there are so many digital pianos worthy of your attention in this catalog, you may want to narrow down your choices using some of the search options on the sidebar. For example, if you select stage digital pianos under the category section, you'll be presented with all the digital pianos that were made for the stage. Once here you have the opportunity to drill down even further and can search by topics like number of keys, MIDI/USB Connections or by whether or not the digital piano has built-in speakers.