Distorted web audio on Mac mini but fine on MacBook Air

Every time I go to the school website on my mac mini, the audio always comes out distorted. I have tried firefox and chrome, but the problem persists. I have tried connecting the mac mini to different audio sources , but still comes distorted.

On the other hand if I open the website on my Macbook Air (14,15) I dont have any issues with audio . I have tried other websites, including youtube and the audio is crisp. I am having particular with this specific website .( Mayo clinic board review) .

If anyone could help Id appreciate it . I'm unable to get studying done on this otherwise and will probably be returning it .

[Re-Titled by Moderator]