Hi,
Thank you for writing to Microsoft Community Forums.
We understand the difficulties you are facing with the audio in the in Windows XP on Hyper-V.
In this scenario, we would suggest you to post your query in TechNet forums, where we have experts and support professionals who are well equipped with the knowledge on Hyper-V to assist you with the appropriate troubleshooting steps
Aditya Roy
Microsoft Community – Moderator