Explained: Mazda's Anechoic Chamber

What is it?

Part of Mazda’s gruelling development program that takes prototype and pre-production vehicles and subjects them to tortures they might encounter in only the most extreme real-world situations. In the anechoic chambers, almost all reflected and rebounding sound and radio waves can be eliminated, allowing engineers to study exactly how new models perform in a carefully controlled environment devoid of any outside interference from sound or radio waves.

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How does it work?

Specially shaped blocks of absorbent materials line the walls of the chambers and are precisely designed to dissipate the energy from sound and electromagnetic waves as they meet the wall. This prevents reflection of waves back through the space and creates the effect of an infinitely large room, which is also insulated from outside noise or radiation.

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Mazda’s chambers also have rolling roads installed for simulating driving conditions while remaining under the highly controlled conditions. The acoustic anechoic chamber allows the accurate monitoring of noise, vibration and harshness (NVH), while the RF (radio frequency) chamber allows the engineers to bombard vehicles with enormous electromagnetic wave energy and study how the sensitive computer electronics respond.

Why does it matter?

Converging wave forms can cause confusing and often misleading results in uncontrolled environments – this applies to both sound and RF waves. Anechoic chambers remove echoes and reflected waves, which allows accurate tuning and development of vehicle systems for greater comfort and reliability. That satisfying thunk of a closing car door was most likely tuned in an anechoic chamber.

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Increasingly important, however, are the effect of radio waves on vehicles, given that sources of radiation are found everywhere from mobile phone communication networks, radar and WiFi equipment, and even cosmic activity. At the Mazda laboratory, the team can bombard a vehicle with radio waves more powerful than a national radio station’s transmitter to try and find system weaknesses before the car hits the road.

Silent Killer

Silent killer People commonly describe the experience of entering an acoustic anechoic chamber – among the quietest places on earth – as eerily weird. Some say the complete silence is so deeply unsettling that they can only endure a few seconds while others say they can hear their own pulse after an extended stay. You wouldn’t want to spend any time in an RF anechoic chamber though. The radio energy is non-ionising and not harmful at regular levels but such is the power of the frequency generators that the RF chamber can be likened to a huge microwave oven.

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