Transmission Loss Tube / Impedance Tube Kits

The transmission loss tube and impedance tube kits provide precision testing tubes equipped with microphones and sound sources.

To perform measurements, material samples are inserted into the tube. A loudspeaker in the tube then emits precisely quantified sound, and the microphones measure the sound pressure level at specific locations along the length of the tube. With PULSE software, you are able to quickly calculate the normal incident acoustic properties of the material based on frequency response functions measured between the various measurement locations.

These kits help you determine sound absorption coefficient and surface impedance by making measurements and calculations in compliance with ISO 10534-2, ASTM E1050 – 12, and transmission loss ASTM E2611 – 17.

USE SCENARIOS

• Researching and developing noise control products by characterizing acoustic material properties and benchmarking competitive products
• Designing acoustic comfort in aircraft and vehicle interiors, by selecting optimal acoustic treatments and barriers
• Testing specified material characteristics and verifying material compliance with regulations before materials are incorporated into manufactured assemblies such as components
• Validating and calibrating computational methods such as acoustical modeling

THREE TESTING TUBE TYPES

Each one of our kits is optimized for specific parameters and methods.

Two-microphone transfer-function method:

• Impedance Tube Kit (50 Hz – 6.4 kHz) Type 4206
• Impedance Tube Kit (100 Hz – 3.2 kHz) Type 4206-A

Four-microphone transfer-function method:

• Transmission Loss Tube Kit (50 Hz – 6.4 kHz) Type 4206-T

See the product data for more information about each specific kit.

MATERIAL CHARACTERISTICS

Whether materials are intended to absorb airborne sound or reduce airborne sound transmission, the acoustic designer or acoustician needs to know the effects of the acoustic materials. A material sample, or coupon test, is a quick and convenient method.

The impedance tube, or standing wave tube, guarantees highly reproducible testing conditions. Prior to testing, the signal-to-noise ratio (SNR) can be determined at each microphone position to ensure accurate results.

The acoustic characteristics of materials are determined in terms of absorption, reflection, impedance, and transmission loss.

CAPABILITIES

• Horizontal mounting of orientation-sensitive materials
• Vertical mounting for simulation of measurements on hanging ceilings
• Wall-mountable
• Determines normal incidence parameters

MATERIAL TESTING APPLICATIONS

Early in the development process of vehicle interiors and aircraft interiors, designers aiming for acoustic comfort need to predict what the acoustical impact will be of components such as trim lining, headliners, seats, and multi-panel systems.

This hardware and its associated software provide input to analytical and numerical tools for the prediction of the sound field in acoustic cavities such as vehicle cabins and aircraft cabins. These tools include finite element modeling (FEM) and the boundary element method (BEM).