Induction loops create a magnetic field that is fairly consistent within the loop and reduces outside of the loop. Outside of a simple rectangular loop there is still an audible signal as far as 4 times the width of the room away from the loop, shown in the graphic on the left below. Spill is also vertical by approximately the same distance, as shown in the second graphic. If another loop system is used with this ‘spill’ area the systems will interfere with each other.
Spill is a problem in many environments where induction loops are useful, for example adjacent classrooms and lecture theatres, cinemas etc.
The solution is usually to use a low spill array, or a cancellation loop. These loop solutions are a little more complex, but are used widely in theatres, educational establishments, cinemas and conference centres around the world. The dramatic improvement in performance can be seen in the third graphic below.
Ampetronic was the first company to develop array systems and continues to lead the industry in design of array systems for a wide range of environments. Ampetronic’s highly skilled and experienced Support team use our proprietary design and analysis tools to produce designs tailored for your application to ensure that spill is not an issue for you and your loop systems.
The Disability Discrimination Act means that it is a legal requirement for assistive listening systems to be installed in an increasing number of places.
When the University of Dundee embarked on building a major new teaching facility, it was a key requirement to include the best possible induction loop systems.
Perimeter loop
Cancellation Loop
Low Spill Array
