Change the voice-encoding scheme used by the radio and intercom objects. Network bandwidth consumed per radio object is a function of the voice- encoding scheme used.
Typical bandwidth consumed per encoding type for a single audio stream:
Another way to reduce bandwidth consumed is to not operate the radios or intercoms in a hot mic condition. If no PTT is available for the operators then you can use a VOX object to handle enabling and disabling the transmission. A VOX object will turn on and off automatically based upon the input signal level provided by the operator microphones. Remember that a radio or intercom used in hot mic mode will be CONTINUOUSLY transmitting onto the network whether you are speaking or not. The addition of the VOX object alters this such that transmission only occurs when speech is active.