Earbuds.com Acoustic Lab Testing & Measurement Methodology
How our independent engineering facility measures frequency response curves, Total Harmonic Distortion (THD), active noise attenuation, and real-world battery drain.
Our Core Acoustic Testing Philosophy
Lab Standards
The Earbuds.com Acoustic Lab exists to replace subjective marketing claims with repeatable, scientifically verifiable electro-acoustic data. Every earbud tested undergoes a battery of automated tests evaluating frequency response against the Harman Target, active noise reduction across three distinct octave bands, microphone speech intelligibility (STI), and continuous battery run-down at 75 dBA.
The Earbuds.com Acoustic Lab exists to replace subjective marketing claims with repeatable, scientifically verifiable electro-acoustic data. Every earbud tested undergoes a battery of automated tests evaluating frequency response against the Harman Target, active noise reduction across three distinct octave bands, microphone speech intelligibility (STI), and continuous battery run-down at 75 dBA.
Unlike review sites that rely solely on human listening impressions, our data is grounded in standardized acoustic fixtures and calibrated laboratory hardware.
Laboratory Testing Rig & Instrumentation
| Testing Rig Component | Specification / Standard | Laboratory Purpose |
|---|---|---|
| Ear Simulator Coupler | IEC 60318-4 (Type 711) | Simulates human ear canal acoustic impedance from 20 Hz to 10 kHz |
| Anthropometric Pinna | Shore 00-35 Durometer Silicone | Replicates anatomical human ear concha and tragus cartilage damping |
| Audio Analyzer | Audio Precision APx525 | Measures THD+N (< -110 dB), frequency linearity, and jitter |
| Acoustic Isolation Chamber | Double-walled Soundproof Booth | Background noise floor < 18 dBA for ultra-accurate low-noise tests |
| External Noise Generator | Four-speaker calibrated pink noise array | Generates standardized 85 dBA aircraft and subway ambient noise fields |
Standardized Test Protocols
- Frequency Response Measurement: Driven via logarithmic sine sweep from 20 Hz to 20,000 Hz at 94 dBA SPL reference. Output plotted against the Harman Target curve.
- Active Noise Cancellation (ANC) Delta: We broadcast 85 dBA pink noise through the chamber speaker array. We record microphone sound pressure inside the artificial ear canal with ANC turned Off, then with ANC turned On. The difference in decibels across 20 Hz – 1,000 Hz represents the true ANC Attenuation.
- Standardized Battery Run-Down: Earbuds are charged to 100%, connected via AAC or LDAC to a calibrated transmitter broadcasting continuous music at a sustained 75 dBA volume level. Playback time is logged automatically via automated audio dropout sensors.
- Total Harmonic Distortion (THD): Measured across the audible spectrum at 94 dB and 100 dB SPL. Any harmonic distortion exceeding 1.0% in the critical midrange (500 Hz – 3 kHz) is penalized.
Frequently Asked Questions
What equipment does Earbuds.com use to test earbud frequency response?
Earbuds.com uses an industry-standard IEC 60318-4 (formerly IEC 711) compliant occluded-ear simulator coupled with an anatomical silicone anthropometric pinna. Measurements are driven and analyzed using an Audio Precision APx525 hardware audio analyzer calibrated to 94 dBA reference SPL at 1 kHz.
What target curve does Earbuds.com benchmark earbud sound quality against?
We benchmark in-ear frequency response against the Harman In-Ear Target Curve (Dr. Sean Olive's research). The Harman target represents the scientifically verified acoustic frequency balance preferred by the overwhelming majority of blind listening test subjects, characterized by a smooth 5 to 7 dB sub-bass shelf and an ear-canal pinna gain peak at 3 kHz.