Editing Vehicle audio (section)

===Active noise control and noise synthesis===
The automobile sound system may be part of an [[active noise control]] system which reduces engine and road noise for the driver and passengers. One or more microphones are used to pick up sound from various places on the vehicle, especially the engine compartment, underside, or exhaust pipes, and these signals are handled by a [[digital signal processor]] (DSP) and then sent to the loudspeakers in such a way that the processed signal reduces or cancels out the outside noise heard inside the car. An early system focused only on engine noise was developed by [[Lotus Cars|Lotus]] and licensed for the 1992 [[Nissan Bluebird]] models sold in Japan.<ref>{{cite web |last1=Peachey |first1=Colin |title=Noise Optimization Technology with Colin Peachey of Lotus Engineering |url= https://www.automotive-iq.com/alternative-powertrains/interviews/noise-optimization-technology-with-colin-peachey-o |work=Automotive IQ |date=1 October 2013 |access-date=25 March 2021}}</ref> Lotus later teamed with [[Harman International Industries|Harman]] in 2009 to develop a more complete noise reduction system, including road and tire noise as well as chassis vibrations.<ref>{{cite web |last1=Filipponio |first1=Frank |title=Lotus and Harman partner on noise-cancelling, noise-creating tech |url= https://www.autoblog.com/2009/04/16/lotus-and-harman-partner-on-noise-cancelling-noise-creating-tec/ |publisher=Autoblog |access-date=25 March 2021 |date=16 April 2009}}</ref> One benefit of active noise control is that the car can weigh less, with less sound-deadening material used, and without a heavy [[balance shaft]] in the engine. Removing the balance shaft also increases fuel efficiency.<ref>{{cite web|url= https://www.automotive-iq.com/alternative-powertrains/interviews/active-noise-control-with-colin-peachey-of-lotus-e |title=Active Noise Control with Colin Peachey of Lotus Engineering |first=Colin |last=Peachey |date=October 7, 2013 |work=Automotive IQ |access-date=25 March 2021}}</ref> The 2013 Honda Accord used an active noise control system, as did the 2013 Lincoln luxury line and the Ford C-Max and Fusion models.<ref>{{cite web|url= http://beta.usatoday.com/story/money/cars/driveon/2012/09/26/cars-noise-cancellation-technology/1590703/ |title=Automakers shush cars with noise cancellation technology |work=USA Today}}</ref> Other operating data may also play a part in the DSP, data such as the engine's speed in revolutions per minute (RPM) or the car's highway speed. A multiple source reduction system may reach as much as 80% of the noise removed.{{Cn|date=June 2023}}

The same system may also be used to synthesize or augment engine noise to make the engine sound more powerful to the driver.<ref>{{cite news|title = America's best-selling cars and trucks are built on lies: The rise of fake engine noise|url= https://www.washingtonpost.com/business/economy/americas-best-selling-cars-and-trucks-are-built-on-lies-the-rise-of-fake-engine-noise/2015/01/21/6db09a10-a0ba-11e4-b146-577832eafcb4_story.html |newspaper=The Washington Post |date=2015-01-21 |access-date=2016-01-16 |first=Drew |last=Harwell}}</ref> For the 2015 [[Ford Mustang]] EcoBoost Fastback and EcoBoost Fastback Premium, an "Active Noise Control" system was developed that amplifies the engine sound through the car speakers. A similar system is used in the [[Ford F-Series|F-150]] [[pickup truck]]. [[Volkswagen]] uses a [[Soundaktor]], a special speaker to play sounds in cars such as the [[Volkswagen Golf|Golf]] GTi and [[Volkswagen New Beetle|Beetle]] Turbo. [[BMW]] plays a recorded sample of its motors through the car speakers, using different samples according to the engine's load and power.<ref>{{cite web|title= The Rise of the Fake Engine Roar |url= http://www.popularmechanics.com/cars/a7923/the-rise-of-the-fake-engine-roar-11291754/ |work=Popular Mechanics |date=2012-08-02 |access-date = 2016-01-16}}</ref>