Hi @denese1966 ,
Try connecting headphones to the tablet and check if the audio is also muffled when listening to them.
If the audio in the headphones is OK, try adjusting the [https://sodeve.net/2015/09/how-to-adjust-audio-balance-left-right-in-windows-10/|speaker balance] to see if the problem is with the Left or Right speaker in the tablet. The audio may sound different when doing this but it should be clear and not be muffled.
If the speaker(s) are the problem, here’s the [http://h10032.www1.hp.com/ctg/Manual/c04499111|maintenance and service guide] for the tablet. Go to p.29 to view the necessary pre-requisite steps and then the procedure to remove / replace the speakers.
The speaker spare part number is ''796818-001'' but unfortunately when I searched online for the part, there were no results for suppliers. You may have better luck.