関連ワード:  jl audio amplifier 4 channel    jl audio amp 4-channel    car audio amplifier 4-channel    car stereo amplifier 4 channel    jl audio marine amp 4 channel    jl audio xd400/4v2 4-channel car amplifier    jl audio rd400/4 4 channel amplifier    are jl audio amps good    how many speakers can you connect to a 4 channel amp    can i run 4 speakers and a sub on a 4 channel amp