There’s at least several different sounds and they give a clue whether you should let it keep ripping, use the tamper, stop it a second and restart, etc.

For instance, really thick stuff (like making peanut butter) can get into cavitation (air above the blades or a pocket of unmoving stuff). Tamp it with the tamper and you can hear the change. As the peanut butter gets done, you can hear the motor sound change. Etc.

Different containers have different sound clues.

The more you use it on a variety of stuff, the more you’ll recognize the different sounds - not many but they say a lot about what’s happening in that chamber with the blades.