How to Test Phones for Noisy Environments?

Royston, United Kingdom, February 11, 2016 --(PR.com)-- Whether walking down a noisy street or talking on speakerphone, telephone users expect clear voice transmission.

Sophisticated signal processing enhances human speech above background noise, but as there are different methods to test this capability, manufacturers cannot always be sure of the best one to use on their products.

To identify the best approach, Brüel & Kjær carried out an investigation contrasting five methods for the reproduction of background noise, including ETSI EG 202 396-1, Higher-order ambisonics, matrix inversion method, ETSI TS 103 224 and matrix inversion method optimized for a specific device.

For each method, the quality of the reproduced sound was evaluated both objectively and subjectively, at microphones close to a device under test and at the ears of a Head And Torso Simulator (HATS). A listening experiment evaluated the perceived quality of the sounds at points where telecommunication devices would typically be placed, around the head.

Following the experiment, the matrix inversion method - optimized for specific microphone positions, such as kdev/kbin – proved to perform the best, both in the objective and the subjective analysis.

The full paper is available to read on Brüel & Kjær’s website.

About Brüel & Kjær

Brüel & Kjær is a world-leading manufacturer and supplier of sound and vibration measurement systems.

We help customers measure and manage the quality of sound and vibration in their products and in the environment. Focus areas are aerospace, space, defence, automotive, ground transportation, airport environment, urban environment, telecom and audio.

Brüel & Kjær has an unparalleled portfolio of sound and vibration equipment and is a long-established designer and manufacturer of innovative instrumentation including sound level meters, microphones, accelerometers, conditioning amplifiers, calibrators, noise and vibration analysers, and PULSE software.

We also design and manufacture the LDS range of vibration test systems, as well as complete airport and environmental monitoring systems: WebTrak, ANOMS, NoiseOffice and Noise Sentinel.

Brüel & Kjær runs a variety of training courses - from basic introductions to noise and its effects to more specialised classes teaching customers how to get the most out of their equipment. Free online training courses, conducted by our expert engineers, run throughout the year too.

Brüel & Kjær is a subsidiary of UK-based Spectris plc, which has annual sales of £1.1bn and employs around 8,300 people worldwide across its four business segments.