Airport extreme multicast setting

I found that when using the airport extreme "N" option on with the higher multicast setting (9-24mbps) the closer you have to be the base ,there really is more information comming from the Extreme base station, it does speed up the internet slightly when loading web pages , but remember most web browses only load at 1.5-3mbs.It does help with downloading and watching movies however.On the contrary when airport multicast setting is set at 6mbps I found that when sitting to close to the base station the connection is'nt as steady or stable, almost as if the signal is better when atleast 10-15 feet away from the station its great when you are working outside or in another room.