If the output audio begins to distort, check the individual channel gains. Distorted sound indicates that either the internal amplifier or the connected loudspeakers are being pushed past their limits. Reduce the volume immediately to prevent permanent hardware failure.
: The QM4 Series Instruction Manual from TDK covers technical safety and power parameters that may apply to the internal power supply unit. QM4 Key Features audio choice qm4 manual link
Since "QM4" most commonly refers to the or potentially a specific Quad Motor controller in engineering contexts, and "Audio Choice" may refer to a specific brand or a general purchasing decision, I have created a technical support article below. If the output audio begins to distort, check