Hello Tom13BE,
Welcome to the HP Forums! I hope you enjoy your stay!
I understand the sound quality of your new notebook isn't as good as you imagined. Based on what you explained, I would contact HP phone support. Since you reinstalled the drivers, it is hard to blame this on software. If a hardware issue is suspected, they can service or replace the product since it is new, or provide an immediate fix.
You can utilize this website to learn how to contact HP appropriately, based on your region: Contact HP Worldwide
Please let me know if you have any other questions. Thanks for choosing the HP Forums. Have a great day!
Mario