Question : What does src="#" mean when used in a bgsound attribute and is it needed?

I am currently using the following line in a html doc which uses javascript to replace the audio source file (which is variable):
<bgsound src="#" id="sound" autostart="false">

My question is can I leave out the src attribute from the bgsound tag.  The # value seems to result in some strange results, almost as though it forces the page to refresh.  When I remove it, everything *seems* to work, but I'm not 100% sure why it is there in the first place and if html specs require it.

Answer : What does src="#" mean when used in a bgsound attribute and is it needed?

I removed the "#" and all seems fine.