Abstract: A detonation detector operable for detecting the intensity of detonation occurring in a combustion chamber of an internal combustion engine. The detonation detector of the present invention includes a mechanical filter mounted on the engine for amplifying vibration signals resulting from detonation, including low intensity, sub-audible detonation signals. The mechanical filter is tuned to a resonant frequency at about the detonation frequency signal in order to attenuate noise signals from the engine and amplify signals at about the detonation frequency signal. A flat response accelerometer is mounted on the mechanical filter and receives the amplified detonation frequency signals and the attenuated noise signals and converts these signals into electrical output signals. An electronic circuit is connected to the accelerometer for amplifying the electrical output signals and filtering the attenuated noise signals.