Well today I was trying some commands  on mysql and suddenly because my command was wrong speaker blow up my ear.  I know  that  it wasn’t the  sound card speaker and it was the system speaker, so the question remain.
How to disable system speaker for mysql ?
Well after a small search I find out that I have to add –no-beep or -b on mysql command.
So the solution is or to add –no-beep or -b or to make a sql.bat and enter in this file mysql –no-beep
My solution was to modify windows path variable to add path to my mysql directory, and after that I run sql from start>run>sql , and I have a client witch don’t beep me any more.
Hope to help u.