Resonator Towers are a defense application of Sonic Weapon technology
Resonator Towers generate a sonic field, of either ultrasonics or infrasounds, which causes pain and feelings of discomfort to enemy targets.
The more advance versions can be set to target only a specific species.
Resonator Towers are generally not lethal unless an affected target stays within their spear of influence too long.
While the overall appearance changes between developer and species, the general appearance is usually similar. It is a tower with some manner of tuning device like a tuning fork or pylons on the roof of the structure.
Despite the name, 'towers' do not always have to be massive things and can simply by satellite dishes on stands.
Resonator towers are generally used and newly colonized worlds, or wild planets, to keep back natural predators and pests.