They all sound the same. Is it possible they all need replacing?

Ok thank you. Wanted to upgrade the Clarion anyway, hopefully that is the cause of the distorted/scratchy speakers.

Cartronics want to charge me £500 just to run diagnostics!!!!

Thank you for your post. No there is no black box. I’m not very tech savvy when it comes to car audio. I’m trying to troubleshoot why all the speakers are distorted/scratchy. Should there be an amplifier in the car somewhere?

I rececently bought the car. It has the Clarion stereo but the sound from all the speakers is very scratchy. Is there meant to be a sub in the boot or is there an amplifier somewhere?-