Pioneer has changed the game with the latest, compact class D GM-D duo of four channel amplifiers. Both the GM-D8704 and its bigger brother, the GM-D9704, can muster Pioneer’s famous open and smooth sound concept, yet do so with efficiency and volume levels you don’t ever really require in a car.

System matching is simple because both amps can be bridged to offer serious power output over two channels at 2Ω resistance, or run in four-channel mode to kick out 100w RMS (4Ω) 4x150w RMS (2Ω) for the 8704, or 4x130w RMS (4Ω) and 4x200w RMS (2Ω).

When bridged the respective outputs double, so the variable low and high pass crossovers can be tuned to deliver both sparkling high end or cab thumping low end frequencies with maximum efficiency.

Price GM-D8704 £139, GM-D9704 – £189

For more info see Pioneer