Adding sound to eliminate sound: a new solution for noisy engines
But chances are, you haven't noticed. That's because automakers have been taking measures to mask the noise.
So where is the noise coming from? Automakers need to reduce fuel consumption. And to do that, they are employing techniques such as variable cylinder management and operating the engine at lower RPM. These techniques can result in more "boom" that permeates the car's interior.
So how are automakers masking the noise? Well, it's not by adding damping materials. In fact, many automakers are removing such materials to help make their cars lighter and more fuel efficient — a practice that can allow more engine sound to reach the driver and passengers.
The weapon of choice is, paradoxically, sound. By playing “anti-noise” (i.e. sound that is directly proportional but inverted to the offending engine tones) over the car’s speakers, automakers can, in effect, make engine noise disappear. This approach is similar to noise-cancelling headphones, but targeted specifically at engine sounds. It's also more complicated, as it must take into account the unique acoustic properties of each vehicle model — properties that change when you open and close windows, add or remove passengers, and so on.
Now here's the thing: The active noise control (ANC) systems currently used by automakers require dedicated hardware. This adds cost and complexity. So the acoustics engineers at QNX have come up with a different approach: a software-based solution that can run on existing infotainment or audio hardware. The result is significantly lower Bill of Materials costs and an ANC solution that integrates better with other audio tasks, including hands-free calling.
Mind you, there are other benefits as well. But don't take it from me. Check out this blog post from my inestimable colleague Tina Jeffrey, who provides the full skinny on the new QNX Acoustics for Active Noise Control product and why it offers a better approach to traditional solutions.