[. . . ] · To keep the heat dissipation mechanism running effectively, wipe the accumulated dust off periodically. with the volume on loud for a long period of time will exhaust the battery, while the engine is turned off or while the engine is idling. [. . . ] In addition, mount in an area that will not prevent the unit from dissipating heat. · Do not mount the unit in the places subject to heat such as near a radiator, in a glove compartment or in insulated areas such as under a car mat that will prevent the unit from dissipating heat. If any other screws are used, there is a risk of loosening the unit or damaging parts inside it. Å Crossover filter switch OFF: Normally, set to this position. (Preset to this position at the factory. ) ON: (For LPF switch) Set to this position when you want to turn on the LPF (Low-pass filter) switch. KS-AX3500: REAR SPEAKER OUTPUT KS-AX3300: SPEAKER OUTPUT (For HPF switch--only for KS-AX3500) Set to this position when you want to turn on the HPF (High-pass filter) switch. The low frequency signals are not applied to the left/ right speaker when a subwoofer is connected. i Input LEVEL controller The input level can be adjusted with this control when this unit is connected to other source equipments. Turn it in the clockwise direction when the output level of the car audio seems low. TERMINAL CONNECTIONS When making the terminal connections. . . Properly fix the terminal with the screw provided by turning it in the direction as illustrated. SPEAKER SYSTEMS This amplifier provides two types of speaker connections: Normal mode and Bridge mode. You can choose either type of connections depending on the speakers configuration equipped on your car. Make sure to comply with the following notes: · Be sure not to connect the "·" terminals of the speakers to a common point. · If the ground wire is common to both left/right and front/rear speaker wirings, this unit cannot be used. [. . . ] · Keep the RCA pin cords away from other electrical cables in the car. · Confirm if the ground lead is connected securely to a metal part of the car. [. . . ]