Just a note to let everyone know how I improved the sound quality of the umbraco tv video tutorials on Windows 7. The sound was very muffled, and to my old ears, almost unintelligible.

• From the speakers icon on your desktop, select the Speakers (Realtek) icon above the volume control.
• Then select the "Enhancements" tab, and then "Loudness equalization"

It's made a huge difference, and I hope this is of help to others.