Sound Level Meter Calibration: Turnaround Times, On-Site Services & How It Works
Tra-Cal Lab has provided ISO/IEC 17025 accredited, NIST-traceable sound level meter calibration for over 35 years — trusted by NASA, the U.S. military, and NIST. We service every major brand, from Brüel & Kjær and Extech to Simpson and PCE, with faster turnaround and lower cost than the OEM. We offer expedited services, on-site calibration and Mid-Atlantic pickup and delivery to keep your operation running. Every certificate includes as-found/as-left data, so your measurements stand up to any audit.
Key Summary
Sound Level Meter calibration verifies indicated sound pressure level against a NIST-traceable acoustic calibrator and reference microphone, checking level accuracy, frequency weighting (A, C, and Z), time weighting (fast, slow, and impulse), and linearity across the measuring ranges, with results documented on a calibration certificate. Standard turnaround is 3-5 business days with overnight rush available, and most sound level meters should be calibrated every 12 months by an ISO/IEC 17025 accredited lab.
Why Choose Tra-Cal?
ISO/IEC 17025 Accredited
Our lab is independently audited every year by ANAB to the industry's most rigorous quality standard, so every calibration is audit-proof.
Overnight Rush Available
When downtime isn't an option, expedited service gets your instrument calibrated and back in your hands overnight or within three days.
NIST-Traceable
Every measurement we make traces directly back to national standards, giving your results documented accuracy you can defend.
Trusted by NASA, the U.S. Military, and NIST
The organizations with the most demanding measurement requirements in the country choose Tra-Cal — yours can too.
Sound Level Meter Calibration Turnaround
| Service | Turnaround |
|---|---|
| On-site Calibration Service | Same-Day |
| Standard calibration with certificate | 3-5 business days |
| ISO/IEC 17025 accredited calibration | 4-6 business days |
| Expedited / rush | Overnight to 3 days |
Sound Level Meter Brands & Models We Calibrate
| Manufacturer | Popular Models We Calibrate |
|---|---|
| Brüel & Kjær | 2230, 2238 |
| Extech | 407735, 407736 |
| Simpson | 884-2, 886-2 |
| PCE Instruments | PCE-432, PCE-SC09 |
| Amprobe | SM-20A |
| Sper Scientific | 840029 |
Don’t see your model?
We support over 100 test equipment manufacturers — contact us and we’ll confirm coverage for your exact instrument.
Equipment & Standards Required
We maintain the following equipment and conditions required to calibrate a sound level meter accurately:
NIST-traceable acoustic calibrator and reference microphone with at least a 4:1 test accuracy ratio
Electrostatic actuator or coupler set for microphone frequency-response verification
Precision signal source and attenuator chain for electrical linearity and weighting-network checks
Manufacturer’s calibration procedure and the applicable IEC 61672 class specifications
Stable environment: 23 °C ± 5 °C, controlled humidity and barometric pressure logging, and NIST-traceable reference standards with a documentation system
How to Calibrate a Sound Level Meter: Step-by-Step
Step 1: Inspect the microphone and preamplifier, then stabilize. Check the diaphragm, grid, and preamplifier threads for damage or contamination, confirm the correct microphone is fitted, and let the instrument and acoustic calibrator acclimate at 23 °C ± 5 °C with ambient pressure recorded.
Step 2: Perform “as found” verification. Record the indicated level at the calibrator reference point and across the weighting networks before any adjustment. As-found data proves whether previously logged noise-exposure or compliance readings were valid.
Step 3: Verify level accuracy, weighting, and linearity. Apply the acoustic calibrator at its reference level, then use electrical injection to verify A, C, and Z frequency weighting, fast/slow/impulse time weighting, and level linearity across each measuring range.
Step 4: Adjust, repair, or reject as required. Apply the manufacturer’s sensitivity correction, replace damaged microphones or windscreens, and service the preamplifier where the design allows. Instruments that fall outside their IEC class after service are documented and returned as limited-use or rejected.
Step 5: Perform “as left” verification and issue documentation. Re-run the full level and weighting set after any adjustment and issue an ISO/IEC 17025 accredited certificate with as-found and as-left data, measurement uncertainties, and NIST traceability.
Pro tip from our lab: Always request as-found/as-left data on your certificate. Without it, you can’t assess whether measurements taken before calibration were reliable — a common audit finding.
How Often Should You Calibrate a Sound Level Meter?
| Usage Profile | Recommended Interval | Notes |
|---|---|---|
| Daily industrial / field use | 6–12 months | Shorten after drift or overload events |
| General lab / bench use | 12 months | Industry-standard default |
| Regulated environments (ISO 9001, FDA, A2LA audits) | Per quality system, typically 12 months | Interval must be documented and justified |
ISO/IEC 17025 does not specify fixed calibration intervals. It requires that intervals be reviewed and adjusted as necessary to maintain confidence in the equipment. Recommended intervals are typically 6–12 months, adjusted based on documented risk assessment and historical stability data per the lab’s calibration program. A2LA and ANAB are accreditation bodies — distinct from quality-system frameworks such as ISO 9001 or FDA requirements.
Frequently Asked Sound Level Meter Questions
Q: How much does sound level meter calibration cost?
A: Sound Level Meter calibration cost depends on the accuracy class of the instrument (Type 1 versus Type 2), whether octave or third-octave filters are included, whether the matching acoustic calibrator and microphone are submitted together, and whether accredited (17025) certification is needed, and whether accredited (17025) certification is required. Contact Tra-Cal for a quote.
Q: Can I calibrate a sound level meter myself?
A: You can perform verification checks against a known reference, but formal calibration requires traceable standards with a 4:1 accuracy ratio and documented uncertainty.
Q: What is the difference between calibration and adjustment?
A: Calibration is the documented comparison against a standard; adjustment is the correction made when readings fall outside tolerance.
Q: How long does calibration take?
A: Standard turnaround is typically 3-5 business days; Tra-Cal offers expedited service options.