How to set up Pioneer GM-D7400M 400W(RMS) mono subwoofer car audio amplifier will be discussed here. First learn about the control and what they do, the gain control, if the sound level is too low, even in a turned up car stereo volume and amp power, turn gain control clockwise. If you detect distortion noise when the volume turn up, turn the gain counterclockwise. When you use it with an RCA equipped car stereo with a standard output of 500mV, set to normal position. When using with an RCA equipped Pioneer car stereo with maximum output of 4V or more, set level to match the car stereo output level.
The low pass filter (LPF) cut off frequency control, with this you can select a cut off frequency from 40Hz to 240Hz.
The power indicator (blue lights) it will light up when the power is switched on.
Input switch, you can input from a car stereo external output or car stereo speaker output. Set the input switch before turning the power on. Because switching the input switch while the power is on can cause a loud noise from the speakers, the power will be shut down by a protection function. If you use external output, slide the switch to the right or RCA. If you use a speaker output, slide the switch to the left or SP, it is important to use the supplied speaker input wire with RCA pin cord.
The bass boost control enable you to select a bass boost level from 0 dB, 6 dB and 12 dB.
Now to set the gain properly, this amp is equipped with a protective function to prevent unit malfunction and speakers from too much output, improper use or improper connection. When you output sound at a high volume etc., the protective function will stop the sound output immediately. Don’t worry it’s not a malfunction, you can restore the sound output when you turn down the head unit’s volume. If sound output is stopped, the gain control could be improperly set. Set the amplifier’s gain to a proper position according to the head unit’s preout maximum output level to ensure continuous sound output at increased head unit’s volume level.
Only distortion will increases and the power will only slightly increased if you set the gain to an improper level. With high output the signal waveform is distorted, if you raise the gain the power only slightly changes.
If you lower the head unit’s volume and set the amp’s gain to the proper position but still having a sound stop frequently you should contact your authorized Pioneer service station.
