All of the auto sound equipment used in the competitor's sound system must satisfy the following guidelines:
All auto sound equipment must be designed for installation and operation in an auto sound environment.
All auto sound amplifiers must be linear in nature.
The amplifiers used in the sound system should be designed for audio reproduction. For clarification purposes, the amplifier's output waveform should be a close facsimile to that of the input signal. In addition, the amplifier's output magnitude should be proportional to that of the input signal. All of these guidelines apply to frequencies between 20 and 80 Hz. The determination as to whether an amplifier is acceptable for use in dB Drag Racing competition shall be at the sole discretion of the dBDRA.
The program material must be reproduced using conventional loudspeakers (subwoofers). The determination as to whether a loudspeaker is acceptable for use in Psychlone competition shall be at the sole discretion of the dBDRA.
The dBDRA defines a conventional loudspeaker as a sound reproducing electro-mechanical transducer that incorporates a cone, surround, basket, and voice-coil.
The loudspeaker must be powered directly by the audio amplifier(s).
Loudspeakers incorporating servo mechanisms, actuators, or any other form of mechanically powered motor are specifically prohibited.
A maximum of 4 electrical conductors may be connected to each woofer as long as no other applicable rules are violated.
A maximum of 2 amplifiers may be connected to each coil on a woofer.
Compressed air, explosive devices, etc. are expressly forbidden.
The same audio system must be used for both SPL and RTA measurements.
Competitors are permitted to make changes to the system settings (volume, tone, equalization, fader, etc.) throughout the competition.
Electrical or physical changes to the sound system are not permitted.