Sonic emitter

The Sonic Cannon was a GDI weapon of unmatched defensive ability, but consumed large amounts of power. It was deployed sometime between the end of the Firestorm Crisis and the beginning of the Third Tiberium War.

Description
Sonic Turrets were reasonably well armored turrets that appeared to be mounts for large spherical containers, with a hole at one end. They fired sonic pulses that appeared to be some sort of whitish waveform that propogated along the ground. This pulse was extremely powerful, enough to kill infantry and destroy most Nod vehicles within its path, including Scorpion Tanks. Against Scrin units, the Sonic Turret was even more effective. GDI soldiers hypothesized that because the Sonic Turret's effects were derived from Sonic weaponry designed to destroy Tiberium, the Scrin, possibly Tiberium based, were affected more strongly by it.

Counters
Similarly to the Obelisk of Light, Sonic Turrets took up huge amounts of power, were extremely powerful, and had very low rates of fire. It is worth noting that the sonic turret had a very slow rate of fire. An astute Nod commander could therefore send in a single weak unit, and then once the Sonic Turret had expended its blast, rush in with his or her main attack.