PRM1 Precision Reference Microphone: Calibration and Measurement Tips

By PreSonus | Wherever sound takes you. | Published: 2026-10-18

Category: Tips & Care

Learn how to use the PRM1 precision reference microphone for accurate room measurement and acoustic calibration. Get step-by-step tips for placement, software setup, and avoiding common mistakes.

Quick answer

The PRM1 Precision Reference Microphone is designed for accurate room measurement using real-time analyzers (RTAs) and spectrographs. To get reliable results, place the mic at ear height in your listening position, use a calibrated preamp, and avoid reflective surfaces. Follow the steps below to set up and interpret your measurements correctly.

Why Use a Reference Microphone for Room Measurement?

Standard microphones color the sound, making them unsuitable for acoustic analysis. The PRM1 is a special condenser microphone with an omnidirectional polar pattern and linear frequency response between 20 Hz and 20 kHz, so it captures the room's true characteristics without adding its own signature. This makes it ideal for use with audio-analysis tools like real-time analyzers (RTAs) and spectrographs.

Setting Up Your Measurement Environment

Place the PRM1 at ear height in your primary listening position, pointing toward the speakers. Keep it away from walls, corners, and large reflective surfaces to avoid early reflections that skew results. Ensure the room is quiet during measurement — turn off fans, air conditioning, and other noise sources. A common mistake is placing the mic too close to a boundary, which inflates low-frequency readings.

Step-by-step calibration and measurement process

Position the PRM1 at the listening position: Place the mic at ear height, aimed at the midpoint between the left and right speakers. Use a mic stand to keep it stable. Checkpoint: Ensure the mic is not closer than 1 meter to any wall or large surface to avoid boundary interference.
Connect to a preamp or audio interface with phantom power: The PRM1 requires +48V phantom power. Connect it to a clean preamp channel on your interface or mixer. Set gain so the level peaks around -12 dBFS during measurement. Common mistake: Forgetting to enable phantom power will result in no signal. Always verify the +48V switch is on before testing.
Open your RTA or spectrograph software: Launch your analysis tool (e.g., Room EQ Wizard, SMAART, or PreSonus UC Surface multi-touch mixer-control software). Set the input to the channel connected to the PRM1. Checkpoint: Confirm the software is receiving signal by playing pink noise through your speakers. Adjust input level if the trace is too low or clipping.
Run a measurement sweep and interpret the results: Play a test signal (pink noise or sine sweep) from your listening position. Observe the frequency response graph. Look for major peaks or nulls that indicate room modes or reflections. Common mistake: Taking a single measurement can be misleading. Average 3–5 measurements with slight mic position shifts for a more reliable picture of the room's response.

Product facts

PRM1 Precision Reference Microphone: The PRM1 is a special type of condenser microphone that provides an accurate reproduction of a room's sound characteristics for use with audio-analysis tools such as real-time analyzers (RTAs) and spectrographs. It has an omnidirectional polar pattern and exhibits linear frequency response between 20 Hz and 20 kHz, so it won't color the sound. This flat response ensures that any peaks or dips you see in your measurement come from the room, not the mic, making it a reliable tool for acoustic treatment decisions.