Subwoofer Troubleshooting - Diagnose your sub issues at home! - YouTube
Car Speaker Polarity Tester, ABS Phase Meter Test Subwoofer Tweeter For Automotive Audio System, For Testing And Troubleshooting Car Audio Systems - Walmart.com
Subwoofer Not Working But Amplifier Has Power - ElectronicsHub
My amp is getting power but my sub is still not working, any advice would be great! : r/CarAV
Soundbar Not Working? How to Fix a Broken Soundbar | Reviews by Wirecutter
My Speaker Isn't Working: How to Troubleshoot Your Home Theater - Polk Audio
Troubleshooting your car amplifier installation
Subwoofer Help And Troubleshooting – Aperion Audio
Troubleshooting and Eliminating Subwoofer Humming Issues — Eightify