Small Anechoic Room for Loudspeaker, Microphone & Component Testing
Compact Anechoic Chamber
Compact and small anechoic chambers designed for loudspeaker characterisation, microphone calibration, earphone and headphone testing, hearing aid measurement, and small electronic component acoustic evaluation. Available from tabletop enclosures (0.5 m³) to walk-in rooms (30 m³), with cut-off frequencies from 200 Hz upward and free-field deviation ±1.5 dB.
Technical Specifications
Applications
- Loudspeaker driver and system characterisation (IEC 60268-5)
- Microphone calibration and directivity measurement
- Earphone, headphone, and in-ear monitor testing
- Hearing aid and hearing instrument measurement
- PA horn and column array directivity characterisation
- MEMS microphone and transducer quality control
- Research and university acoustics laboratories
Overview
Many acoustic measurement applications require free-field conditions but do not demand the scale of a full automotive or industrial anechoic chamber. A compact anechoic chamber provides the same free-field measurement environment — just sized to the test object and measurement distance required.
HEMU Acoustics compact anechoic chambers cover four size classes:
**Tabletop Enclosure (0.5–5 m³)** — For consumer electronics, earphones, in-ear monitors, and hearing aid measurements. Interior lined with 100–150 mm wedges achieving a cut-off frequency of 500–800 Hz. Background noise ≤ NC-20. Typically used with a measurement microphone at 10–50 cm distance. Folded test windows on two sides provide access without disturbing the acoustic field.
**Benchtop Chamber (5–20 m³)** — For loudspeaker drivers, microphones, and small transducers. Wedge length 150–300 mm, cut-off frequency 200–400 Hz. Background noise ≤ NC-15. Interior height 1.2–1.8 m. Test object suspended on wire frame to minimise reflections.
**Walk-In Chamber (20–50 m³)** — For loudspeaker systems, public address (PA) horns, and directional microphone arrays. Wedge length 300–500 mm, cut-off frequency 150–200 Hz. Background noise ≤ NC-15. Sufficient test distance (1–2 m) for far-field loudspeaker measurement per IEC 60268-5.
**Custom Laboratory Chamber (50–200 m³)** — For array antenna measurement, directivity characterisation, and precision calibration. Wedge length up to 800 mm, cut-off frequency 100 Hz. Full ISO 3745 qualification achievable.
All sizes are available as fully anechoic (6 anechoic surfaces) or hemi-anechoic (5 anechoic + 1 reflective floor) configurations.
Key Features
±1.5 dB Free-Field Condition (200 Hz Upward)
Free-field condition verified to ±1.5 dB (ISO 3745 criterion) above the chamber cut-off frequency. For walk-in chambers (300 mm wedges), cut-off is typically 200–250 Hz. For tabletop enclosures (100–150 mm wedges), cut-off is 500–800 Hz. All chambers are acoustically qualified and supplied with a free-field deviation measurement report.
Four Size Classes — Tabletop to Walk-In
Tabletop (0.5–5 m³) for earphones and microphones; benchtop (5–20 m³) for drivers and transducers; walk-in (20–50 m³) for loudspeaker systems; custom laboratory (50–200 m³) for array and directivity work. All classes share the same wedge system and panel construction principles — different only in scale.
Melamine Foam Wedges (≥ 0.95 NRC)
Standard wedge material is open-cell melamine foam — lightweight (10 kg/m³), self-supporting, fire-rated (B1/B2 class), and achieving NRC ≥ 0.95 from cut-off frequency upward. Fiberglass wedges are available for higher mechanical durability. Custom wedge profiles (pyramids, flat absorber tiles) available for very small enclosures.
≤ NC-15 Background Noise
Mass-law isolation achieved through 50–100 mm steel panel walls (small enclosures) or composite concrete/steel construction (walk-in rooms). All chambers are placed on anti-vibration pads or spring isolators depending on host environment. Mechanical service penetrations use acoustic gland fittings. Target background noise NC-15 to NC-20 depending on size.
Loudspeaker Measurement per IEC 60268-5
Walk-in compact chambers (1.5–2 m test distance) meet the minimum test distance and background noise requirements for IEC 60268-5 loudspeaker frequency response measurement. Microphone stand mount points are included on the ceiling and two side walls. Optional turntable base for polar measurement.
Fast Delivery and Installation
Modular panel construction ships flat in standard freight. Tabletop and benchtop enclosures are delivered pre-assembled. Walk-in chambers assemble in 2–5 days on site with no structural work required. Tabletop models are plug-and-play with a single power connection. All models include a calibration report and operating guide.
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Our acoustic engineers respond within 24 hours.