How Imitated Exhaust Sounds Complicate Car Audio Enhancements

      BMW

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      Few things irritate car enthusiasts more than artificial exhaust sounds. Perhaps my viewpoint is biased due to my extensive time online, but I can't recall ever encountering someone who enjoys engine noise projected through their speakers. Beyond feeling inauthentic, the feature known as Active Sound Design creates substantial difficulties when attempting to upgrade simple components like a subwoofer.

      I became aware of this after discussing with Ken Ward, the technical marketing manager for Elettromedia SpA. In my view, Ward is an audio expert, as he creates comprehensive training courses for dealers and installers focused on the nuances of sound production. He also co-founded Musicar Northwest, a shop renowned for its exceptional work. Ward initially mentioned the issues with artificial exhaust noise in our previous conversation, leading me to reach out for more details.

      “The basic premise I communicate is that car manufacturers have three primary goals for the audio system,” Ward explained. “The least significant of these is to ensure that it sounds decent. That is the least of their concerns.”

      “The primary objective for them is to utilize the speakers for non-entertainment sounds.”

      BMW has consistently incorporated Active Sound Design, or piped-in exhaust noise, in its vehicles—even those that already produce pleasant sounds.

      Ward clarified that “non-entertainment sounds” encompass a wide range of noises. These can include seatbelt alerts, open-door notifications, or hands-free phone calls, which are the main priorities for OEMs concerning car audio systems. Fake exhaust noise also falls into this category, meaning that manufacturers prioritize maintaining those functionalities over creating a high-quality audio experience for music or spoken content.

      This is where the aftermarket car audio industry comes into play, but OEMs create challenges. Third-party installers, whether they are high-end audio designers or more conventional specialty shops, must navigate features like Active Sound Design (ASD) and Active Noise Cancellation (ANC). The latter resembles your preferred over-ear headphones, which use microphones to pick up external noise and produce sounds to cancel it out.

      Both ASD and ANC rely on a network of microphones that instruct a vehicle's stereo on what sounds to emit—be it the aggressive growl of a GR Corolla’s turbocharged three-cylinder engine or an out-of-phase hum to mitigate road noise. While they serve distinct purposes, there is often considerable overlap between the two systems. This overlap becomes apparent when an audio installer accesses a car’s wiring harness, only to find that one small adjustment disrupts numerous functions.

      “The inaugural Cadillac Escalade was the first model equipped with integrated noise-canceling microphone technology,” Ward shared. “If you had a window open or a door ajar, the ANC system wouldn’t activate. Consequently, when a customer arrived, the typical procedure involved rolling up the window and closing all the doors. Suddenly, it felt like a jet plane was taking off inside the cabin.”

      “This caused frustration for everyone because the vehicle wasn’t ready, and you had to determine a solution. Ultimately, we needed to locate the individual microphones that Bose had installed in the headliner. Each microphone connected back to the amplifier, and we had to disconnect them. Once we did that, everything was fine.”

      ANC systems have only become more sophisticated since the early Escalade’s release. Ward forwarded me an example wiring diagram of a Genesis GV80, which featured not one or two, but eight microphones. He described it as a recent challenge he assisted a dealer with:

      “Those microphones didn’t connect directly back to the amplifier. Usually, microphones plug into the soundboard, and in this case, the amplifier acted like the soundboard. In the Genesis, each microphone is attached to a small circuit board, which contains a network chip, and they’re connected in a daisy-chain loop.”

      “If you disconnect one microphone, you affect them all. This is acceptable in this case since all microphones on that network were solely for ANC.”

      In the new Escalade, overhead microphones may manage ANC functions at times, but they also enable hands-free calling, which can’t be easily removed. Cadillac

      Others can be even more frustrating. Ward noted that the new Escalade repurposes ANC microphones for hands-free calling. In such instances, disconnecting the ANC microphones isn’t an option since it would remove safety features. While Escalade owners can deactivate some of these features via a toggle on the infotainment screen, it doesn’t entirely resolve the issue, as some microphones remain active.

      It's crucial to understand that these complications aren't exclusive to luxury vehicles. Ward referenced the new Chevrolet Silverado equipped with a basic, non-Bose sound system as another example. It also utilizes piped-in exhaust sound, and Ward stated, “I don’t know how to turn it off. I don’t know anyone who knows how to turn it off. Additionally, this vehicle’s factory audio system lacks bass.” This is particularly frustrating because those