Concert halls, opera houses, theatres, music performance venues, arenas, stadia, recording studios, cinemas, music practice rooms, hospitals, schools, universities, residential buildings, offices and leisure facilities…all these buildings need careful acoustic design to make them sound good, to protect them from nearby noise sources, to make them productive and pleasant places to live or work in and to make them commercially successful. There is a huge variety in the tasks for the acoustic engineer: design meetings with architects and other engineers, noise surveys of existing and new sites, design using computer and physical models, communication of the design to the client and design team, project management, site supervision and commissioning of the finished projects. This offers a wonderful balance between the creative, scientific and practical skills and is a career that will always present new experiences and challenges.
We are all consumers of audio through our mobiles, mp3 players, game consoles, computers and televisions. Acoustic engineers are involved in the design of all these devices. This is more than just the design of loudspeakers that make sound, developing methods to manipulate sound through digital signal processing is a major area of audio engineering (just think how the invention of mp3 has revolutionised how we consume music). Major manufacturers of consumer devices such as Apple, Samsung and Microsoft all employ acoustic graduates in research and development. Out and about we listen to sound systems designed by acousticians. In cinemas the surround sound system is designed to allow directors to scare us in horror movies. In sports stadiums, railway stations and shopping centres electroacoustic design has to ensure clear intelligible messages to allow safe evacuation in case of emergencies.
Noise is a major issue for society: 80 million EU citizens live in unacceptably noisy areas. Professionals who work in the field of environmental noise make up about half of the Institute of Acoustics membership, i.e. around 1,500 in the UK. Most work in local authorities or acoustic consultancies. Environmental health officers consider noise in planning new developments, such as housing affected by noise, or new noisy activities, and enforcement of existing noise concerns including the sources of complaints from the public. Consultants in environmental noise work in small specialists firms or large multinational consultancies, including engineering firms. The job requires a wide range of skills including numeracy and good communication skills. Junior staff measure noise from time to time and use computer models to predict noise levels from new developments such as roads, railways and industrial plant. Reports are prepared for public readership as a well as by regulators. Consultancy can be a demanding job, but one which offers great variety and career progression.
Noise can also harm animals. A growing area of research in acoustics is bioacoustics, which is examining how man-made noise is affecting the well-being of whales, birds and other animals.
Noise control and product sound
Our lives our surrounded by technologies that make noise, from the whine of a vacuum cleaner to the roar of a car engine. It is the job of acousticians working in noise control to find ways of quietening machines. Acousticians working in aeroacoustic research will try to attenuate engine noise to reduce the noise annoyance caused by overflying aircraft. A car manufacturer might be looking to reduce the noise in the cabin so the driver can hear their radio better. A manufacturer of a vacuum cleaner might be subtly changing the design so it sounds like the device is powerfully sucking up the dirt and yet is not too loud. Acoustic engineers also work on vibration, whether that is designing out the juddering brakes on a lorry or measuring how railways cause nearby buildings to vibrate.
Traditionally, this was a relatively small area of research examining the physics of musical instruments and the mathematical principles behind music. Nowadays, it is a much broader field concerned with researching and describing music and its perception. This includes: the human voice (the physics and neurophysiology of singing); computer analysis of music and composition; the clinical use of music in music therapy, and the perception and cognition of music.
Speech and hearing
There are numerous careers which are based on aspects of acoustics related to this area: They include: audiologists – people who making acoustic measurements to determine in what way(s) a person’s hearing may be impaired, making appropriate diagnoses and prescribing solutions; speech and language therapists – people who investigate the ways in which a person has difficulty communicating via speech and taking remedial action; speech technologists – those who research, design or develop new tools for processing, recognising and understanding human speech (including identifying speakers) and enabling computers to produce more “natural sounding” synthetic speech; acoustic consultants for building and/or sound system design – these people advise architects and engineers in aspects of the design and construction of buildings and systems for which speech being clearly audible and understandable plays a particularly prominent role, including classrooms and theatres; forensic phoneticians – experts who help the police or legal specialists analyse recorded samples of speech.
Ultrasound waves can be used to obtain images of the foetus in the womb, and detect cracks in critical systems such as an aircraft structure or pressure vessel. Likewise ultrasound can be used to verify the mixing of foodstuffs like mayonnaise, measure the properties of the sea-bed, and detect the cracking of a material as it breaks. At higher amplitudes ultrasound can also be used to produce effects such as the welding of plastic materials or the destruction of tumour tissue or kidney stones. The application of ultrasound in all these areas requires a good understanding of how sound travels and interacts with materials and is an example of physical acoustics. Other areas include seismology.
Neither light nor radio waves travel far in the ocean, but sound can be transmitted over very long distances, sometimes hundreds of miles. Because of this, underwater sound has probably been used by marine animals to navigate, communicate and locate prey for millions of years. However, the sinking of the Titanic in 1912 and the start of the First World War provided the impetus for the practical application of underwater acoustics by human scientists and engineers. Underwater sound is an indispensable tool, both for military applications and for commercial use. Acoustic signals are used to locate commercially valuable fish, to determine the safest routes for shipping, and to explore the Earth's geological formations or search for oil deposits beneath the ocean floor. Potential careers in underwater acoustics cover a diverse range of activities, such as designing sophisticated sonar hardware, computer modelling of sound propagation in the ocean or carrying out experiments and tests at sea, and the need for technological advancements in underwater acoustics offers many rewarding job opportunities for graduates in acoustics.