Hi @Banex1, I am very sorry to hear about this.
Unfortunately it is very hard to tell from a distance whether this behaviour is caused by the software or if it is caused by the accident that you mentioned. Have you been able to carry out a quick test of the speakers in the support app in order to see if the hardware is working as intended? To do this, find and tap Settings > Support > Xperia Tests > Microphone and speakers.
Another thing that you can try is to reboot your phone in safe mode to see if the behaviour of the top speaker persists there. All apps downloaded from Play Store is temporarily deactivated while in safe mode and by doing so, you can see if this behaviour is caused by a downloaded app. For more information on safe mode and how to use it, click here.
If the behaviour of the top speaker persists in safe mode, My suggestion is to repair the software using a computer and Xperia Companion. Keep in mind though that a software repair will erase all user data from the phone, so make sure to do a backup of your user data before the repair.
If none of these measures manages to improve the sound quality from the top speaker, I would suggest that you get in contact with your local support team in order to have your phone sent to an authorized service center to be examined and possibly repaired. If you have any questions regarding the service such as routines, warranty and consumer laws, these kind of questions are best answered by your local support team as well.
Let me know how it goes!
