[plt-scheme] DrScheme tour screencast (sound volume too low)

I tried watching the DrScheme tour screencast
http://plt-scheme.org/tour.html but the sound volume is very low and
also seems to only come out of the left speaker. Even at full blast
it's difficult to hear clearly.

Also, as long as I'm complaining ;), the resolution seems quite low as
well. Compare to platypope's Emacs screencast:
http://platypope.org/yada/emacs-demo/ .

Thanks.