A camshaft sound refers to the sound an engine makes when an aggressive cam is installed. Camshafts are metal tubes found inside the cylinder head. When the camshaft spins, it opens the valves of an engine and produces power. Aggressive camshaft profiles open the valves for longer periods of time, which allows for more power, and often creates louder sounds.
There are several different types of performance cam shafts that can be installed onto a vehicle. The street level performance cam shafts are made to retain a legal sounding engine, while still being capable to produce good power. Race level camshafts are loud and produce the most power.