Ceiling speakers can be used without a receiver by connecting them to an external amplifier. These speakers are usually passive, meaning they don't have built-in amplifiers, and they rely on the power provided by the amplifier. To use ceiling speakers without a receiver, you need to wire each speaker to the binding posts on the amplifier using speaker cables. The amplifier will then provide the necessary power to drive the speakers and produce sound. This setup allows you to enjoy audio playback through the ceiling speakers without the need for a separate receiver. By following these steps, you can easily set up and use ceiling speakers without a receiver.