AirPort "Multicast"?

[SnowLeopard2008]

I was just trolling thru the setup options in AirPort Utility of my AirPort Express. I found this "Multicast" option under AirPort > Wireless > Wireless Options. What does this mean? And if I set it to 11mbps (highest) what will improve? Screenshot below.

 

[waw74]

from the help file

Controlling the quality of audio and video streaming
If your AirPort network has certain audio and video streaming servers or other applications with multicast capability, you can control the quality of the transmission by setting the multicast rate.

To set the multicast rate:


Open AirPort Utility, located in the Utilities folder in the Applications folder on a computer using Mac OS X, and in Start > All Programs > AirPort on a computer using Windows.


Select the device you’re setting up, and then click Manual Setup. Enter the password if necessary.

Click AirPort in the toolbar, and then click Wireless.


Click Wireless Options, and then choose a rate from the Multicast Rate pop-up menu.

If you set the multicast rate high, only clients on the network that are within range and that can achieve the speed you set will receive transmissions.

You can set the multicast rate to 1 megabit per second (Mbps) to extend the range of your network beyond the default.

also check out http://discussions.apple.com/message.jspa?messageID=6488220

quick answer, i believe is no it will not, it will actually keep you from connecting if you have a weak signal.