There are many models of wireless transmitters on the market. All of these transmitters have one similarity. They all stream music via a wireless signal. However, different models differ on how reliable they are able to work. Wireless transmitters have to cope with many problems. Those problems in particular are multipath fading caused by reflections of signal components by walls. Multipath fading causes deep notches within the frequency band which is a problem for mobile receivers as well as stationary receivers.
One way that wireless music receivers cope with multipath fading is by using two antennae. This is called antenna diversity. Antenna diversity works by the receiver switching between two antennae. If one antenna has poor reception, the receiver switches over to the second antenna which has a stronger signal. Often the transmitter also has two antennae. This allows 4 possible combinations.
Another way to improve reliability is to use frequency hopping. Usually fading only affects a few frequency channels. By hopping to another channel, the reception can be improved. Most cordless phones and Bluetooth devices use frequency hopping. One more advanced method is called adaptive frequency hopping. This method scans for free channels and avoids any channels which are occupied by other transmitters.