Q: Using RF-AP305 ,no sound...is it normal on a MacBook Pro ???

What year is your MBP? Some of the older ones late '09 I think needs to have a seperate audio cable.

Read thru these links to make sure that the cable/adapter meet vesa spec. You can also try a pram reset:

pwer off the MBP, power it back on holding the keys:  COMMAND+OPTION+P+R  continue to hold these keys till you hear the start chime 2 times then release.

Also try connecting with the TV off then power TV on.

http://support.apple.com/kb/HT4241

http://support.apple.com/kb/PH10671

Hope this helps