Toa of Sonics were vulnerable to their own power, which was why there were not many of them around. Jerbraz described this as "one of the Great Beings' little jokes." The Order of Mata Nui wanted to train Krakua how to use his power to its fullest potential before he became a Toa.
Toa-level control over sonics would allow a being to shatter stone at the right pitch.
Silence was essentially a special Sonics power.
Power scream was sonics.