Quick answer
Distortion that gets worse as you turn it up is usually gain set too high, or your amp starving for power. Turn the gain down using a safe setup method, then check your ground and power wire gauge.
Problem
- Harsh, clipped or distorted sound when you turn it up.
Symptoms
- Harsh buzz above moderate volume.
- Bass flattens suddenly, and you may smell a hot voice coil.
- The LED on your amp blinks under load.
Cause
- Gain too high for your headunit pre-out voltage.
- Undervoltage at your amp on idle with big draws.
- Driver mechanically bottoming from a mis-tuned crossover.
Fix Step-by-step
- Turn the amp gain to minimum, set your headunit volume to a sane test level, then bring the gain up using the safe method in our gain guide.
- Check your ground integrity and conductor gauge for the amplifier current draw.
- Swap the L/R channels to see if the distortion follows the speaker or the upstream path.
Notes
Related: Setting amplifier gains.