2013 Cadillac ATS
John Goreham's picture

Cadillac’s new 2013 ATS highlights high-tech sound management

New technologies continue to combat old noise issues as well as some new ones.

The new 2013 Cadillac ATS is a very quiet car, due in part to some old technology, but also because of to some new innovations. For decades automakers have tried to make cars quieter. Any backyard mechanic who has worked on a car has taken of a body panel to find foam-like materials placed inside by the manufacturer to make the car quieter to the driver. The easiest sound deadening material for a casual observer to see is the under-hood and under-trunk fiber-felt that helps make the car quieter inside the cabin, and has some aesthetic and safety roles as well. With the modernization of our vehicles has come the modernization of the sound management.

Noise Management
Noise reduction was always the goal in the past and the 2013 Cadillac ATS is no exception to the rule. However, taking away all the noise also creates issues for manufacturers of performance cars. One problem is that more and more performance cars sound lousy to the ear of an enthusiast because to them V8 burble and roar is the correct sound of a car that is desirable. In order to help deal with that in cars such as Ford’s new Focus ST and Mazda’s Miata, manufacturers actually bring sound into the car from the intake manifold. It turns out that the noise we enthusiasts like and always associated with “exhaust” is actually helped by the intake manifold’s song. With new technology available options abound. BMW and Audi took heat form many fans for introducing into the cabin what amounts to a recording of good car sounds. Enthusiast’s ire was somewhat tempered by the fact that the “recordings” were of the actual car – and because it works. James Murphy , vehicle performance engineer commented on the subject saying “Not all noise is unwanted, especially in a vehicle like ATS. While wind rush penetrating a closed window is undesirable, the driver does want to hear the vehicle respond with power during spirited driving.”

Sound Deadening Materials
Cadillac’s 2013 ATS may be a smaller car than most Cadillac owners are used to, but they expect nothing less than total luxury from the new sports sedan. With “sports” being a big part of that car’s category weigh is an issue, so Cadillac has added lightness where they could by changing the material they might have used otherwise. For example, rather than add more sound deadening to combat wind noise in the ATS, the engineers specified a different type of glass laminate for the windscreen. Instead of one single piece of formed steel in a given component Cadillac instead may have choses a laminated steel sandwich to do the same job. Quiet steel has been a relatively recent discovery in the automotive manufacturing world and it has been shown to be a cost effective way to design in noise reduction rather than the old approach which was basically, make the car then add foam to kill the bad noises. Cadillac still does add foam in areas that make sense like in the roof liner. But that is a place where a bit of foam might also be a safety feature. Just because the technique is old does not mean it isn’t the right choice. Sound deadening can also be a performance related choice. In the new 2013 Viper, SRT (formerly Dodge) offers versions of the supercar without sound deadening material. This saves about 40 pounds and costs nothing to implement. By comparison the company spends thousands to save that same amount of weight by using carbon fiber hood and complicated manufacturing for the Viper’s wheels.

Active Noise Cancellation

Cadillac’s new ATS will also feature a now mature technology called active noise cancellation (ANC). ANC didn’t come to market first on a mainstream car in an ultra-luxury model, but rather was first introduced to the masses by Honda in the 2005 Odyssey minivan to help hide the noise made when its cylinder deactivation system was working. Many people don’t realize that fuel savings and sound reduction are so closely related. The 2013 ATS will use technology from Bose, who first brought consumers noise cancellation headphones to help reduce noises that are in the low, bass type range. This technology is novel because it actually generates some noise that cancells out the sounds that are unwanted.

New Noise Challenges
Some noises I the 2013 Cadillac ATS are new and the result of changes in technology. For example, Cadillac was quite frank about describing its new Spark Ignition Direct Injection system as being a noise maker. The automaker says that the sound of this new fuel-saving, power creating fuel management system “produces a “tick-tick-tick” diesel engine type of noise when the vehicle is idle.” This particular noise is so tricky to filter out that multiple strategies are required.

The all new, 2013 Cadillac ATS is making a lot of noise in the marketplace, but not much in the cabin.

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