Hi,
Please do try these troubleshooting steps that may help in identifying the issue if it's the speaker itself that has the problem.
- Start by uninstalling/reinstalling the sound card driver.
- Open Device Manager and uninstall the Sound driver.
- Once uninstalled reboot your laptop and it should reinstall the driver automatically.
- If it will not install, download and install the latest sound card driver from the manufacturers site.
- After installing the latest driver do observe if the sound would be a lot better.
- If it doesn't solve the problem then it's the built in speaker itself that is faulty.