The Exciter effect adds high frequency harmonics to the audio signal which makes it sound brighter. It creates harmonics related to the original sound instead of boosting them like an equalizer does. It works by high pass filtering the input signal, distorting it, then adding it back to the original signal.
Input Gain - The amount of gain applied to the input signal. The LED shows when it is over 0 dB.
Drive - The amount the signal is distorted. The Input Gain also effects the amount of distortion.
Filter Frequency - The high pass filter's cutoff frequency.
Depth - The amount of harmonics added to the original signal.
Output Gain - The amount of gain applied to the output signal. The LED shows when it's over 0 dB.