Final answer:
A reference microphone for setting equalization of a speaker system should have a flat frequency response and be isolated from environmental noise or interference.
Step-by-step explanation:
A reference microphone for setting equalization of a speaker system should be capable of accurately capturing the sound produced by the speaker system. It should have a flat frequency response, meaning it doesn't add or subtract any frequencies when recording. This ensures that the equalization settings are adjusted based on the true response of the speaker system and not the microphone.
Additionally, the reference microphone should be isolated from any environmental noise or interference that may affect its performance. This can be achieved through physical isolation, such as using a microphone stand or shock mount, or by using a directional microphone that focuses on capturing sound only from the speaker system.