A wireless microphone or mic comprises a transmitter and a receiver device that work together to transmit audio signals over a wireless radio frequency (RF) connection. The transmitter is connected to the microphone itself, whereas the receiver is connected to the sound system or amplifier, and they both must be present for the wireless mic to work effectively. The mic converts audio waves into electrical signals, which are then transmitted by the transmitter over a specific frequency to the receiver. The receiver then receives the signals, converts them back to audio waves, and sends them to the sound system or amplifier for output. So, to answer the question, a wireless mic needs a receiver to effectively transmit audio signals wirelessly.