SW Series Circular Impedance Tube – High‑Precision Acoustic Material Testing Solution

Key Specifications at a Glance - 4 Performance Metrics

Product Overview - ISO/ASTM/GB Compliant Impedance Tube Systems

The BSWA SW Series Circular Impedance Tube Systems are high-precision acoustic material testing platforms that measure normal incident sound absorption coefficient, specific acoustic impedance, and transmission loss in full compliance with ISO 10534-2, ASTM E1050, ASTM E2611, and GB/T 18696.2 standards^[1]. Using the dual/quad-microphone transfer function method, the SW Series replaces the traditional standing wave ratio method, improving testing efficiency by more than 90% while delivering higher data stability and repeatability.

The system employs a dual-tube design with 100 mm and 29 mm inner diameters to achieve seamless full-frequency coverage from 50 Hz to 6400 Hz. Paired with high-precision MPA416 pre-polarized microphones, a 3.5-inch high-power speaker, and professional USB-powered data acquisition hardware, the SW Series provides a complete turnkey solution for material R&D, simulation validation, and quality control in automotive, construction, and industrial acoustics^[2].

Key Advantages - 4 Core Strengths

Transfer Function Method: Standard-Compliant Core Principle

The SW Series uses the dual/quad-microphone transfer function method to replace the traditional standing wave ratio method, achieving over 90% improvement in testing efficiency with higher data stability^[1]. This method complies with GB/T 18696.2, ISO 10534-2, ASTM E1050 for absorption testing, and ASTM E2611 for transmission loss testing, ensuring measurement results are internationally recognized and directly comparable across laboratories.

Dual-Tube Design: Full Frequency Coverage from 50 Hz to 6400 Hz

Two complementary tube diameters cover low and high frequencies seamlessly: the SW4201/SW4221 (100 mm inner diameter) extends down to 50 Hz, while the SW4601/SW4661 (29 mm inner diameter) reaches up to 6400 Hz^[2]. Combined use supports comprehensive testing of automotive interior materials, building acoustic materials, and sound insulation products across the full frequency range relevant to human hearing and regulatory requirements.

High-Precision Hardware Configuration

The system features high-precision MPA416 pre-polarized microphones with typical sensitivity of 50 mV/Pa, a 3.5-inch high-power speaker with 30 W peak power, and professional data acquisition with high sampling rate and high dynamic range^[2]. USB-powered operation eliminates the need for external power supplies, simplifying laboratory setup and enabling portable field measurements when required.

MCR-IMP Software: Integrated Workflow Support

The dedicated MCR-IMP software provides complete workflow support with two specialized modules: MCR-IMPS for sound absorption coefficient testing and MCR-IMPT for transmission loss testing. Features include one-click transfer function measurement, real-time signal quality monitoring, and automatic standard report generation, all fully compatible with SW Series impedance tubes^[2].

Model Comparison - SW4201/SW4221 vs. SW4601/SW4661

The dual-tube configuration allows users to select the optimal tube diameter based on the target frequency range and material application^[1]. The following comparison details the specifications and typical applications for each model pair.

SW Series vs. Traditional Standing Wave Method - 5 Criteria Compared

The transfer function method used by the SW Series offers fundamental advantages over the traditional standing wave ratio method in efficiency, accuracy, and workflow automation^[1]. The following comparison illustrates why modern laboratories and quality control environments favor impedance tube systems.

Core Applications - 3 Professional Scenarios

1. Material R&D

For acoustic foam, composites, and sound insulation cotton development, the SW Series provides precise absorption coefficient and transmission loss data to guide material formulation and structural optimization^[2]. Researchers can rapidly iterate on material designs with immediate, standards-compliant feedback on acoustic performance changes.

2. Simulation Validation

The SW Series generates reliable empirical data to validate acoustic simulation models built in COMSOL, ANSYS, and other finite element platforms^[2]. Measured impedance and absorption data serve as boundary condition inputs and verification benchmarks, ensuring simulation accuracy matches real-world material behavior.

3. Quality Control

For production environments requiring rapid batch testing and screening, the SW Series enables efficient throughput with one-click measurement and automatic report generation^[2]. Manufacturers in automotive, aerospace, and construction can verify incoming material batches meet acoustic specifications before integration into final products.

User Core Benefits - 3 Pillars

Accurate & Standards-Compliant

Full compliance with ISO 10534-2, ASTM E1050, ASTM E2611, and GB/T 18696.2 ensures measurement results are internationally recognized, directly comparable, and suitable for formal reporting and certification^[1]. High-precision MPA416 microphones and professional data acquisition hardware guarantee reliable, traceable data.

Efficient & Automated

Over 90% efficiency improvement compared with traditional methods means faster project turnaround and higher laboratory throughput. MCR-IMP software automates the entire workflow from measurement to report generation, eliminating manual calculation errors and reducing operator training requirements.

Versatile & Expandable

The dual-tube design covers 50 Hz to 6400 Hz, addressing automotive interior materials, building acoustics, industrial sound insulation, and research applications in a single system. USB-powered data acquisition and modular software architecture allow easy integration into existing laboratory infrastructure.

FAQ

What parameters can the SW Series measure? The SW Series measures normal incident sound absorption coefficient, specific acoustic impedance, and transmission loss, providing a complete characterization of acoustic material performance in accordance with international standards.

What international standards are supported? The SW Series complies with ISO 10534-2, ASTM E1050, ASTM E2611, and GB/T 18696.2, covering both absorption coefficient testing and transmission loss testing with internationally recognized methodology.

How much is testing efficiency improved over traditional methods? Over 90% compared with the traditional standing wave ratio method. The dual/quad-microphone transfer function method eliminates manual probe traversal and enables one-click automated measurement with immediate results.

Is the SW Series suitable for automotive and construction materials? Yes. The dual-tube design covers 50 Hz to 6400 Hz, making it widely used for automotive interior trim, sound insulation cotton, building acoustic panels, and composite material development in both industries.

Is dedicated software available for the SW Series? Yes. MCR-IMP provides full workflow support with two modules: MCR-IMPS for sound absorption testing and MCR-IMPT for transmission loss testing. Features include one-click measurement, real-time signal monitoring, and automatic standard report generation.

What is the frequency range of each tube diameter? The 100 mm tube (SW4201/SW4221) covers 50 Hz to 6400 Hz for low-frequency absorption testing, while the 29 mm tube (SW4601/SW4661) covers 500 Hz to 6400 Hz for high-frequency sound insulation testing. Combined use provides seamless full-band coverage.

References

[1] International Organization for Standardization, "ISO 10534-2 -- Acoustics -- Determination of sound absorption coefficient and impedance in impedance tubes -- Part 2: Transfer-function method." https://www.iso.org/standard/22851.html

[2] BSWA Technology, "SW Series Circular Impedance Tube Systems." Product page. https://www.bswa-tech.com

[3] ASTM International, "ASTM E1050 -- Standard Test Method for Impedance and Absorption of Acoustical Materials Using a Tube." https://www.astm.org/e1050-19.html