Acoustic Calibration Laboratory & Microphone Calibration Service
Whether routine ISO 9001 quality audits of your existing measurement microphones (B&K, G.R.A.S., Microtech Gefell, NTi, Svantek, MiniDSP, Behringer), sound level meters, and calibrators, or purchasing lab-verified precision hardware: We test every unit simultaneously on our traceable reference chain. At its heart are precision reference calibrators and our €50,000 APx555 from Audio Precision.
📦 Send in Your Existing Meter or Microphone for Calibration
Traceable factory calibration performed in-house at our Dresden lab (incl. report, sticker & .cal file) or accredited DAkkS calibration via our external accredited partner laboratories.
✨ Purchase New Microphone or Calibrator Pre-Calibrated by Our Lab
Individually calibrated USB measurement microphones (lab-verified UMIK-2, Class 2 USB Art. 6533, ATD5-T), selected Behringer ECM8000, or regulated Center 326 calibrators.
4 Simple Steps to Your Newly Calibrated Instrument
Select Calibration Service Online
Select the required factory or DAkkS calibration for your microphone, calibrator, or sound level meter below and add it to your quote.
Ship Instrument to Dresden Lab
Ship your well-packaged instrument (including a copy of your quote) to: Dr. Jordan Design, Schanzenstrasse 27, 01097 Dresden, Germany.
In-House Lab Audit (or DAkkS Partner)
Traceable factory calibrations are executed directly in-house on our APx555 and Spektra SQ-4.2 test bench. Accredited DAkkS calibrations are handled via our accredited external partner laboratories.
Return Shipment with Certificate
Insured return shipping with printed calibration certificate, new calibration sticker, and – for our factory calibrations – custom digital correction files (.cal / .txt / .req).
Calibration & Standard Finder: What Does Your QA System Require?
Select your instrument type and required certification level – our advisor immediately displays the exact technical test scope and matching service.
Measurement Microphone Test Scope (IEC 61094-5 / IEC 61672)
2. Absolute sensitivity measurement at 1,000 Hz / 94.0 dB SPL referenced to our primary standard B&K 4231 (reported in mV/Pa and dBV/Pa).
3. Simultaneous 2-channel pressure chamber frequency response (31.5 Hz to 20 kHz) inside the Spektra SQ-4.2 against our transfer standard G.R.A.S. 40AE.
4. Printed test report plus custom calibration files (.cal / .txt / .req) for Akulap, REW, NTi XL2, Svantek, Smaart, and Dirac Live.
Our €50,000 Lab Reference Chain & Metrological Traceability
Behind the scenes of our Dresden calibration lab: How our cascaded traceability hierarchy operates, why a single 1 kHz check misses hidden drop damage, and how our simultaneous 2-channel pressure chamber eliminates room reflections.
Audio Precision APx555 Dual Analyzer
Digital and analog precision reference analyzer. Two phase-synchronous channels capture the DUT and reference mic simultaneously with < 1.0 µV self-noise and Δ < ±0.01 dB linearity.
Spektra SQ-4.2 Precision Pressure Chamber
Fully enclosed electro-acoustic precision coupler for secondary calibrations from 31.5 Hz to 20 kHz. Couples both capsules symmetrically to the exact same homogeneous pressure field.
G.R.A.S. 40AE 1/2" Transfer Standard
High-precision internal transfer standard for simultaneous differential measurement inside the pressure chamber. Cross-validated prior to every measurement cycle against our primary standard B&K 4231.
Brüel & Kjær 4231 Primary Reference
Our primary acoustic reference standard (Master) for absolute sound pressure traceability (94.0 / 114.0 dB SPL). Externally calibrated by an accredited laboratory on a strict 24-month schedule.
High-SPL & Ultra-Low-Noise Test Rig
Specialized test setups for ultra-low self-noise evaluations (down to 5.5 dB(A) with G.R.A.S. 40HL) as well as high-SPL distortion testing up to 170 dB peak.
Dokumenten-ID: DJD-QM-TRACE-2026 | Rev. 2.2 Official QM Documentation • Declaration of Metrological Traceability Declaration of Metrological Traceability & Test Equipment Monitoring
Documentation of the cascaded calibration hierarchy of our Dresden test laboratory for your ISO 9001 audits
▼ Open Document ▲ Collapse
Declaration of Metrological Traceability & Test Equipment Monitoring
Documentation of the cascaded calibration hierarchy of our Dresden test laboratory for your ISO 9001 audits
1. Purpose and Normative Framework
2. Primary Reference Standard (Acoustic Traceability)
• Reference Instrument: Brüel & Kjær Type 4231 (IEC 60942 Class 1, Serial No.
2402714)• Hierarchy Status: Primary Reference Standard (Master)
• Monitoring Interval: External accredited calibration (DAkkS / ISO 17025) on a fixed 24-month cycle.
3. Internal Working Standards (Transfer Standards)
• Hierarchy Status: Internal Working Standard (Transfer Standard)
• Monitoring Procedure: Rather than isolated external checks, these capsules undergo continuous cross-validation and absolute level referencing prior to every test cycle against the externally certified primary standard (Brüel & Kjær 4231, SN
2402714), ensuring an unbroken internal traceability chain.4. Electrical Reference & Signal Analysis (Audio Analyzer)
• Reference Instrument: Audio Precision APx555 (Serial No.
11083)• Hierarchy Status: Precision Reference Audio Analyzer
• Monitoring & Self-Validation: Given the inherently negligible electrical tolerances and long-term converter stability, system integrity is verified prior to every measurement cycle via hardware self-diagnostics (APx AutoCal) and automated loopback routines against strict acceptance criteria: Loop frequency response flatness (20 Hz – 20 kHz) within Δ < ±0.01 dB and loop residual harmonic distortion (THD @ 1 kHz) below −115 dB (< 0.00018%).
5. Measurement Uncertainty Conclusion
11083), and strict anchoring of absolute sound pressure levels to the externally accredited primary standard (Brüel & Kjær 4231, SN 2402714), overall system measurement uncertainty is minimized. Metrological traceability across all relevant acoustic and electrical quantities is methodologically complete.⚠️ Caution After a Drop Impact: Why a 1 kHz Field Calibrator Misses the Damage! (#064 & #027)
When a measurement microphone is dropped or bumped, the outer housing often looks completely unharmed. Even beneath the protective grid, the diaphragm may not show a visible dent – yet the mechanical shock frequently alters the internal diaphragm tension, shifting its resonance frequency. The treacherous field trap: When inserted into a 1,000 Hz calibrator, the mic often still reads an exact 94.0 dB! However, between 4 kHz and 16 kHz, the frequency response suddenly deviates by 3 dB to 8 dB. That is why our lab always inspects the bare diaphragm optically first and then measures the complete frequency response from 31.5 Hz to 20 kHz.
Comparison of the 6 Microphone Calibration Methods (Tech Article #074)
1. Free-Field Substitution Method (Anechoic Chamber)
Essential for determining free-field response including housing diffraction and high-frequency directivity. Requires a full anechoic chamber.
2. Precision Sound Pressure Chamber (Spektra SQ-4.2 / IEC 61094-5)
Our primary laboratory procedure: Simultaneous 2-channel comparison of test mic and Class 1 reference inside the same closed pressure cavity (31.5 Hz to 20 kHz, >60 dB SNR) with zero room influence.
3. Electrostatic Actuator (IEC 61094-6)
Purely electrostatic excitation of a metal condenser diaphragm via a high-voltage grid. Fast production check, but omits protective grid and acoustic body diffraction.
4. Reciprocity Calibration (IEC 61094-2 Primary Standard)
The fundamental primary method used by national metrology institutes (such as PTB). Derives absolute sensitivity from electrical and geometric base units using three coupled capsules.
5. Kundt's Tube (Impedance & Standing Wave Tube)
Classic waveguide method for defined planar sound waves at low frequencies and for measuring sound absorption coefficients and material impedance.
6. Time-Windowed Nearfield & Room Measurement (Impulse Gating)
Enables quasi-anechoic high-frequency checks in standard rooms by gating out the impulse response prior to the first wall reflection. Physically blind at low frequencies.
All Calibration Services by Category
Select the calibration service required for your instrument. All prices feature full Net/Gross transparency and can be added to your instant PDF quote with a single click.
Cluster 1: In-House Traceable ISO 9001 Factory Calibrations in Dresden (Cat. 40 & 15)
Performed directly in-house on our Audio Precision APx555 & Spektra SQ-4.2 reference chain. Ideal for over 95% of industrial, consulting, and ISO 9001 tasks with fast turnaround (typically 3–5 business days) and custom correction files.
Cluster 2: Accredited DAkkS Calibrations via External Partner Laboratories (Cat. 42)
Accredited calibrations per DIN EN ISO/IEC 17025 with official DAkkS certificate for sound level calibrators, measurement microphones, and sound level meters. Executed via our accredited external partner laboratories (including pre-check and full handling by us).
All prices plus shipping costs (FCA Dresden). Gross prices incl. 19% VAT are indicated alongside net prices.
Pre-Calibrated in Our Lab: Buy New Hardware Pre-Calibrated
Save separate mail-in costs and waiting times: We individually calibrate and verify selected measurement microphones, calibrators, and handheld analyzers on our APx555 test bench prior to dispatch.
Lab-Verified USB Measurement Mics
Through individual APx555 calibration, we transform USB measurement microphones (such as our lab-verified 1/2" UMIK-2, Class 2 Art. 6533, or High-End ATD5-T) into traceable precision tools for Akulap and Akulap Mobile.
Individually Calibrated ECM8000
Eliminate +2 dB to +7 dB high-frequency batch variance: Pick your exact unit by serial number in our interactive curve selector – including .cal file, APx555 report, and optional signed certificate.
Verified Calibrators & Bedrock Kits
Closed-loop Class 2 calibrators (Center 326 Art. 7002), lab-audited B&K 4231 Class 1 references, and turnkey Bedrock SM30/SM50/SM90/AM100 analyzers – verified in Dresden before shipping.
📺 Lab Demonstration Videos
Akulap kalibrieren mit Schallpegelkalibrator
1-Klick-Kalibrierung bei 94 dB / 114 dB nach IEC 60942.
Kalibrierdaten für Behringer ECM8000 in REW laden
Verwendung der von uns erzeugten .cal/.txt Korrekturdateien.
Frequently Asked Questions on Acoustic Calibration
Do you perform the calibrations in-house – and what is the difference between factory calibration, DAkkS calibration, and state verification? ▼
1. Traceable Factory Calibration (performed in-house): All factory calibrations (Art. S101, S102, S104, S105) are executed directly in our Dresden laboratory on our cascaded reference chain (Primary Standard Brüel & Kjær 4231 SN 2402714, Transfer Standard G.R.A.S. 40AE, Spektra SQ-4.2 chamber, and Audio Precision APx555 SN 11083). You receive a signed test report with documented traceability plus digital correction curves (.cal/.txt) – ideal for over 95% of industrial and ISO 9001 QA tasks.
2. Accredited DAkkS Calibration (via external partner laboratories): Whenever authorities or test codes formally require a certificate bearing the official DAkkS accreditation symbol per DIN EN ISO/IEC 17025, we handle this service (Category 42, e.g. Art. DAKKS-CAL) through our external DAkkS-accredited partner laboratories.
3. Official State Verification (Eichung per § 62 MessEG): Performed exclusively by state verification authorities for pattern-approved sound level meters in legal enforcement.
Can you calibrate my existing USB measurement microphone (e.g. MiniDSP UMIK-1 / UMIK-2) or third-party brands? ▼
Yes, of course! We calibrate measurement microphones across virtually all brands in our lab: Alongside standard 1/2" and 1/4" condenser and electret capsules (Brüel & Kjær, G.R.A.S., Microtech Gefell, NTi Audio, Svantek, Bedrock, Beyerdynamic, Behringer), we routinely calibrate USB measurement microphones such as the MiniDSP UMIK-1 and UMIK-2 (using precision adapters for the 12 mm UMIK-1 body). Inside our Spektra SQ-4.2 pressure chamber, we capture the exact frequency response from 31.5 Hz to 20 kHz plus absolute sensitivity and provide ready-to-use calibration files for Akulap, REW, Smaart, or Dirac Live.
My measurement microphone or calibrator was dropped – is a quick 1 kHz / 94 dB check sufficient? ▼
No – that is one of the most common pitfalls in acoustic measurement! An impact often alters the mechanical tension of the thin diaphragm without leaving a visible tear. At 1,000 Hz, a field calibrator may deceptively still read 94.0 dB, while the high-frequency response between 4 kHz and 16 kHz drops or peaks by several decibels. Only a full-band pressure chamber measurement (Art. S102) reliably exposes this damage. Similarly, unregulated calibrators (such as the AZ8930) can drift after a drop and require laboratory verification and readjustment (Art. S101).
What documentation and digital calibration data do I receive after testing? ▼
You receive your instrument securely packaged with an updated calibration sticker (recommended interval: 12 months for microphone capsules, 12–24 months for calibrators and sound level meters). Included is a printed factory calibration certificate signed by Dr.-Ing. Frank Jordan documenting ambient lab conditions (temperature, atmospheric pressure, humidity), measured actual values (mV/Pa, dBV, dB SPL, THD), and the reference chain (DJD-QM-TRACE-2026) used for your ISO 9001 audit. For microphone calibrations (Art. S102), you also receive digital correction files (.cal / .txt / .req) ready to load into Akulap, REW, NTi XL2, or Smaart.