A team of voice quality specialists, known affectionately as the ‘Golden Ears’, are playing a key role in the development of BT’s 21st Century Network in the UK – part of BT’s global IP network for the delivery of next-generation communication services.
The Golden Ears mission is to make sure the high quality of voice communications over today’s PSTN networks is maintained when BT switches over to the IP-based 21st Century Network. The team, which is based at BT’s labs at Adastral Park in the UK, has more than fifty years experience in voice quality testing for telephone networks and equipment.
“Despite the growth of new services in the telecoms industry, for many customers voice is, and will remain, the most important communications service,” says Andy Heron, senior project manager for voice quality engineering. “In making the transition to the 21st Century Network it’s imperative that we get the voice quality right and the specialist skills of Golden Ears testing is a key part of that.”
Members of the Golden Ears team have highly refined audio senses. These have been likened to the palette of a wine connoisseur or the olfactory expertise of a ‘nose’ in the perfume industry.
“It takes a combination of natural aptitude and a great deal of experience to hone these skills, to be able to detect and distinguish subtle variations in the quality and clarity of voice carried over a telephone line. It’s not about developing Superman-like hearing, where you can hear a pin drop at five miles - its more about being able to recognise, identify and determine the cause of the most subtle changes which would be imperceptible to most users,” says Andy Heron.
BT also employs sophisticated tools and techniques for automated quality testing and network monitoring, with voice testing performed under many different network and environmental conditions.
“We have an array of technology to do the scientific measurement, but its human voices we’re carrying across our network and human ears listening at the other end - the human experience and perception is all important. That’s why we also do subjective testing using real people - a cross section of the telephone-using public - who do not have any in-depth experience or knowledge of these systems,” adds Andy Heron.
In the UK, BT’s 21CN involves the migration of 30 million customer lines and the withdrawal of the legacy voice (PSTN) platform. BT expects to complete this £10 billion programme by the end of the decade.
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