Impedance Tube Systems (SW422 / SW477 / SW4000 Series)
2026-02-28BSWA Technology manufacture impedance tubes compliant with ISO 10534-2, ASTM E1050, and GB/T 18696.
Model Selection Guide:
| Model | Tube Diameter | Frequency Range | Primary Use |
|---|---|---|---|
| SW422 | Ø100 mm / Ø30 mm | 50 Hz–6.4 kHz | General building materials |
| SW477 | Ø100 mm / Ø29 mm | 80 Hz–6.4 kHz | Automotive interiors |
| SW4000 | Customizable | Extended ranges | Research applications |
Transfer Function vs Standing Wave:
- Transfer Function Method (ISO 10534-2): Modern standard using two microphones and FFT analysis. Faster, more accurate, covers broader frequency ranges. This is what SW422/SW477 use.
- Standing Wave Ratio Method (ISO 10534-1): Legacy approach requiring frequency sweeps and manual peak measurements. Rarely used in contemporary testing.
Sample Size Flexibility:
Standard tubes accommodate circular samples (100 mm or 29/30 mm diameter). For irregular shapes or smaller samples:
- Custom square tubes available (F50, F100 for 50×50 mm or 100×100 mm samples)
- Small-diameter tubes (down to 10 mm) for specialized research
- Heated or underwater variants for extreme conditions (inquire for custom development)
Software & Licensing:
MCR module. Licenses are machine-locked (not dongle-based). If you replace your computer:
- Contact support with old machine code
- Receive new authorization file within 24 hours
- No additional fees for same user/institution
Measurement accuracy is equivalent (±0.05 absorption coefficient deviation in round-robin tests).
