Competitors may use the program material of their choice while competing.
The program material being played may originate from any type of source unit that has been specifically designed to play music. This includes cassette decks, CD players and changers, DVD players and changers, VCR's and VCP's, MP3 units, AM/FM/Satellite radio tuners, smartphones, tablets, etc.
Both wired and wireless connections between the source unit and the sound system are permitted. This includes RCA cables, Fiber-Optic cables, Bluetooth, WiFi, etc.
The program material must consist of music. No "test tones" are permitted. Test tones "camouflaged" as music or "songs" that are advertised as music but are, in fact, test tones will not be permitted in competition.
The program media may be from a commercial source (such as a CD you purchase) or a custom, homemade recording.
Adjustments to the sound system may be made while the vehicle is being metered as long as no other applicable rules are violated during the adjustment process. (Metering is the process where the Sound Pressure Level or SPL of your vehicle is measured.)
The contestant's vehicle may be running while in the judging lanes as long as the following conditions apply:
Operation of the vehicle or sound system must not endanger the judge, competitor, spectators, or any real or personal property on the premises.
The vehicle's parking brake must be set.
The wheels must be chocked.
The hood must be closed.
The maximum engine idle speed must not exceed 2000 RPM.
A remote "engine kill switch" must be easily accessible from outside of the vehicle for those competitors that are bolting (clamping, strapping, etc.) the doors of the vehicle closed while in the judging lanes.
It is the competitor's responsibility to comply with the conditions listed above. Competitors found to be in violation of one or more of these conditions may be eliminated from the competition.
The contestant must be outside of the vehicle while the vehicle is being metered and all doors, windows, and other openings to the vehicle must remain closed during this time.
Exception - Contestants who elect to remain inside of the vehicle during metering must meet the following requirements:
The contestant must sit in the driver's seat. Additional passengers are prohibited.
The contestant must wear adequate hearing protection at all times. Removal of the hearing protection while inside of the vehicle will result in a zero score.
The contestant must sign a dBDRA entry form that includes a waiver stating that the contestant understands that "exposure to high sound pressure levels may result in temporary or permanent hearing loss".
It is the contestant's responsibility to take adequate safety precautions when operating the sound system at high sound pressure levels.