I got my 2013 Mazda 3 Sport certified used just last year, and one of the first things I noticed was the overpowering bass on the stock (non-Bose) system. It's so loud that I currently have it turned to -4 and it's still a little bass heavy. To my surprise, my speakers are now blown and crackle, and I'm left wondering how this is possible. How do stock speakers blow when they're matched with a stock head unit from the factory? This is the first time I've blown factory speakers and that includes the Honda Civic I had for 16 years that had 350,000 KM's on it.

Is there something wrong with the system? Is it normal to have to turn the bass to -4 just to get it to sound normal?

Could the previous owner have turned up the bass on the headunit somehow outside of the Trebel/Bass/Fade/Bal control on the unit itself?

I guess I have no choice but to get aftermarket speakers now.