Loud constant scratching sound if anything but muted

Yes, your iPad speaker is "Blown" and will need replacing. This is common unfortunately due to the small size of the speaker itself and the volumes the iPad can reach. This is not an easy repair. Lots of things can break while doing this repair if you do not know what you are doing. Here is the link for parts and repair guides:

iPad 2 Wi-Fi EMC 2415のスピーカーアセンブリの交換

If you do not want todo this repair yourself, I would recommend contact a professional for assistance. Good luck and have a wonderful day!