Free field Calibration with REM Headset too low

Product(s): Measure · Primus
Applies to version: All current versions
Audience: External – Customers
Difficulty: Intermediate
Estimated resolution time: 15–25 minutes
Last updated: 2026-06-27
Article type: Troubleshooting guide

Quick summary

Calibration readings are unexpectedly low when performing free-field calibration with a REM (Real Ear Measurement) headset. This guide walks through probe validation, calibration sequence, systematic verification, environment setup, hardware checks, and loudspeaker configuration to restore accurate measurements.

⚙️ Before you begin

Make sure the testing room is quiet - background noise directly affects calibration accuracy.
Have a spare probe set available for hardware testing if needed.
Do not move the speaker or patient position during calibration.

Step 1: Verify probe calibration

Is the initial probe calibration valid and are the probes functioning correctly?

✅ Yes → Proceed to Step 2.
❌ No → Confirm the initial probe calibration is valid and ensure both probes are functioning correctly before continuing.

→ Check if the issue is resolved. If yes - you're done ✓. If no - continue to Step 2.

Step 2: Follow the correct calibration sequence

Have you followed the correct free-field calibration sequence at the correct distance?

✅ Yes → Proceed to Step 3.
❌ No → Take these steps in order:

Conduct free-field calibration at a 50 cm distance from the speaker.
Immediately follow with Probe Tube Calibration at the same 50 cm distance.

→ Check if the issue is resolved. If yes - you're done ✓. If no - continue to Step 3.

Step 3: Calibrate and compare both probes

Have you calibrated and compared results for both left and right probes?

✅ Yes → Proceed to Step 4.
❌ No → Take these steps:

Perform free-field calibration on the left probe.
Repeat free-field calibration on the right probe.
Compare results between left and right - note any significant differences, as this may indicate a faulty probe.

→ Check if the issue is resolved. If yes - you're done ✓. If no - continue to Step 4.

Step 4: Optimise the testing environment

Is your testing environment quiet and free from vibrations or external noise?

✅ Yes → Proceed to Step 5.
❌ No → Take these steps:

Ensure the testing room is completely quiet - turn off ventilation or other noise-generating equipment.
Stabilise probe positioning so it does not shift during calibration.
Minimise external noise interference and use sound-dampening techniques if necessary.

→ Check if the issue is resolved. If yes - you're done ✓. If no - continue to Step 5.

Step 5: Test with an alternative probe set

Have you tested with a different set of probes to rule out hardware damage?

✅ Yes → Proceed to Step 6.
❌ No → Try an alternative probe set and repeat the calibration. Check the original probes for physical damage or wear - replace them if worn.

→ Check if the issue is resolved. If yes - you're done ✓. If no - continue to Step 6.

Step 6: Verify loudspeaker selection and alignment

Is the correct loudspeaker selected and properly aligned in the calibration settings?

✅ Yes → Proceed to the escalation path below.
❌ No → Take these steps:

Double-check the loudspeaker selection in Tools → Sound Field Calibration settings - it must match the physically connected speaker.
Verify the loudspeaker is correctly aligned and positioned at the right distance and angle.

→ Check if the issue is resolved. If yes - you're done ✓. If no - proceed to the escalation path below.

🔺 Escalation path

If none of the above steps resolved the issue, contact Auditdata Support.

Please have ready:

Specific calibration values observed (e.g. expected vs. actual dB readings)
REM headset model and serial number
Probe details (model and condition)
Description of the testing environment
Your account name and contact details
Which steps above you already tried
Any error messages or unusual behaviour observed

✅ Expected outcome

After completing these steps, free-field calibration should return accurate readings. Measurements should be consistent between left and right probes, and REM headset performance should be reliable.

📝 Additional notes

Precise calibration is critical for accurate audiometric testing - always follow the correct sequence (free-field first, then probe tube at the same distance).
Environmental factors - including ventilation noise and room reflections - significantly impact calibration accuracy.
Regular probe maintenance prevents calibration issues. Replace probe tubes at recommended intervals.
Related articles: REM or Free-Field Speaker Calibration Issues or Inaccuracies · Measure - High-Frequency Transducer Not Responding · Measure – Transducer Connection Issues and Incorrect Free Field Calibration

Need more help? Visit the Auditdata Help Centre or contact our support team.