Alternator Whine — Symptom: Whining tone, pitch rises and falls exactly with engine RPM. Present whenever engine runs. Audible even with no music playing (volume up, no source se…
Amplifier Hiss — Symptom: Constant hissing sound from tweeters or midrange. Present even with no music playing and head unit volume at zero. Does not change with engine RPM.
Finding Rattles and Buzzes — Rattles are often blamed on speakers when they're actually in loose trim panels, screws, or miscellaneous items in the car.
Head Unit Won't Power On — Step 1: Check constant 12V wire (yellow). Should be 12V at all times, key on or off.
Headlights Dimming with Bass — Symptom: Headlights visibly pulse or dim with bass beats. More obvious at night. Worse at high volume.
Ignition / Engine Noise — Symptom: Popping, ticking, or clicking noise. Rate matches engine RPM or ignition cycle. Not a tone — more erratic than alternator whine.
One Channel Dead — Step 1: Test with known-good speaker directly at amp output. If channel still dead: problem is in amp or input signal.
Parasitic Battery Drain — Symptom: Battery dead after parking for hours or overnight. Battery tests good when charged.
Repeatedly Blown Fuses — Important: Never replace a fuse with a higher-rated fuse. Fuses protect wires. A larger fuse allows more current before blowing — which means the wire overheat…
Subwoofer Over-Excursion — Symptom: Subwoofer moving violently, sounds like it's "slapping" or bottoming out. May hear a hard clicking or thumping mechanical sound at bass peaks.
Subwoofer Voice Coil Thermal Damage — Symptom: Subwoofer produces distorted sound, especially at sustained high levels. Performance degrades during a session and improves after cooling. Eventually …