Active Noise Cancellation Hushes Cadillac ATS’ Interior
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Ask any car guy (or gal) about what can make or break the perceived quality of a perfect car — and they’ll likely tell you that sound (or noise) can play a huge role in the highly subjective assessment. Managing noises and sounds that a driver (and the vehicle’s other occupants) may want to hear (such as the engine note) and others that they don’t (such as wind noise or the drone of an exhaust system) has become an essential element of vehicle development, and a tell-tale sign of an automaker’s engineering prowess as appreciated by consumers.
“Not all noise is unwanted, especially in a vehicle like ATS,” said vehicle performance engineer James Murphy. To that end, Cadillac’s compact-luxury performance sedan — the ATS — makes use of active and passive methods to manage cabin sound, including high-tech electronics and sound-deadening materials.
On the active noise cancellation side of the equation, the ATS utilizes three Bose microphones inside the cabin that monitor and adjust interior sounds to create an optimal driving environment for the occupants of the sport sedan. The three mics use sound control technology co-developed with Bose to proactively monitor the ATS’ cabin for unwanted low frequency “boom” noises happening between 40Hz and 180Hz, and then neutralize it by offsetting the noise with a counterbalance of sound through the car’s speakers. The microphones are strategically placed above the interior door frame on the front driver and passenger sides, as well as the rear driver’s side, to listen to the same sounds the occupant would hear.
When it comes to passive noise cancellation, the ATS features sound deadening materials (such as covers and foams, among others) woven into the vehicle in unassuming areas. These materials work to absorb and block noise from passing cars along with eliminating vibrations, and speak to the overall attention to detail by engineers. The areas of the ATS containing sound deadening materials include:
- Roof – between the roof’s base sheet-metal and the interior lining, the ATS is treated with sound- deadening material that lessens noises like rain hitting the vehicle.
- Windshield and front side windows – Instead of traditional tempered glass, the ATS features acoustically laminated glass, which is made up of a sheet of sound-absorbing laminate sandwiched between two layers of glass. This limits the sound of wind rush and other traffic while driving.
- Rocker sections are injected with sound-absorbing foam that reduces noises made by the tires on varied road surfaces.
- Undercarriage – An underbody aero shield and wheelhouse covers serve a dual purpose of blocking road noise while driving, and trapping powertrain noise at idle.
- Powertrain – The ATS’s engine uses laminated steel, acoustic covers, isolation, and glove-fitted foam materials that contribute to reducing noise and vibrations under the hood. All of these materials are especially helpful in minimizing noise from the high pressure Spark Ignition Direct Injection system, which typically produces a “tick-tick-tick” diesel engine type of noise when the vehicle is idle.
Working in tandem, the active and passive noise-canceling systems reduce sound levels by three decibels — which is the equivalent a car that’s 50 percent quieter.
Given that most initial ATS buyers traded in a vehicle from another make, it seems that consumers are taking notice of the high level of detail invested in the ATS by Cadillac. Now, how about that eight-speed transmission?
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Excellent article….sounds almost the same as Verano’s Quiet Tuning car process I read about here….exactly what a Cadillac should be; quiet and smooth.
Active noise cancellation cracks me up. Seriously, it’s funny that manufacturers need to
create sounds inside a car to counter the sounds the car makes. Ford made a big deal a few years back about it’s “Quiet Steel” used in firewalls of F-150s to deaden sound.
Silence seems to be the goal – to have the inhabitants of a luxury car have a serene environment where they can enjoy a nice sound system or just feel isolated from the outside. Nothing does this better than an electric powertrain. Tesla Model S testers are coming away startled at just how pleasant it is to cruise along in near silence – not needing any audio/mechanical trickery to accomplish this feat. Chevy Volt owners know this feeling as well. The goal with electric motoring is to now better isolate road, tire and wind noise in all elements and to make solid cars that don’t squeak or have rattles that an ordinary ICE car sometimes covers up due to it’s natural “white” noise and harmonics from it’s complex mechanical makeup.
considering that the primary source of noise [when cruising in a modern car] is wind and road noise, i doubt that an electric drive drivetrain makes that much of a difference.
EXTREMELY WELL STATED!!!!!!!!!!!!!!!!!!!!!! Kudos to you James! I own a 2000 Lexus LS 400 that is DEAD silent. I cannot even hear the engine or exhaust at all. Even under hard acceleration the engine / exhaust are EXTREMELY muted. As a worshipper of Luxury in a car, this is of UTMOST importance to me. I need to feel like I’m gliding on smooth ice cream (yes, that “magic carpet ride”) and don’t want to hear ANYTHING. That does not mean I do not want my car to be quick. Just the opposite.
And my LS is DAMN quick when I want it to be. Like an ABSTRACT FORCE is snapping my head back in the seat (BUT IN NEAR TOTAL SILENCE). An incredible feeling I enjoy even after 11 years of owning my car. The world and our jobs are chaotic enough. I don’t need my car (my home away from home) assaulting me as well by making me feel every bump in the road and the engine /exhaust screaming its so called “note” *rollseyes* into my ears.
Lexus has however TOTALLY RUINED their newer vehicles. In short they are HORRENDOUS (especially the RX and ES) are NOISY, STIFF RIDING hunks of garbage that whackjobs and nutjobs with nothing in their heads pay a pretty penny for. I love Lexus for its reliability, and it still shines in this area. But the vehicles are too unrefined and harsh to be even called Luxury vehicles. The LS 460 is a slight exception. But even it has become NOISIER, ROUGHER and HARSHER-RIDING than its predecessors. Big mistake by Lexus to somehow please the SMALL MINORITY of nutjobs who INTENTIONALLY want to hear this so called “engine note” *rollseyes*.
Generally speaking I would NEVER have considered something like a Tesla. But this car with its DEAD SILENT electric powertrain is becoming more and more appealing to me, even with its other major shortcomings like RANGE etc. Its EXACTLY what I want in a car (from an enjoyment point of view). EXTREME speed, with TOTAL SILENCE!!!
Another cool engineering feat is when manufacturers work days and weeks on tuning car’s exhaust note to capture the feel they believe that buyer wants. Mazda worked hard to tune the MX-5 Miata’s exhaust note to give it that particular growl a sporty person expected – but not to make it too harsh or intrusive. Performace boats have had “quiet choice” technologies for years to switch their exhaust pipes from through-the-hull to underwater, and Corvette appeared a few years back with it’s own tunable exhaust. A cool idea to give you on-the-fly choice as to the level of sound you wish.
Have you guys seen the hilarious videos on YouTube of that device you plug into your cigarette lighter to make your subcompact sewing machine car sound like a Cobra V-8, a Viper V-10 or a Ferrari V-12? Maybe buyers of EVs can just plug one of those into their car to regain old familiar vibes…. I love the silence in electric cars myself.
German tuner Brabus made a Tesla Roadster available ( don’t know if they sold any ) and here is one of the features they added ( quote from their sales material ) :
“To give the sports car a more exciting sound the BRABUS electronics specialists have developed a �space sound generator.� The occupants on-board the Tesla Roadsters can choose from several simulated engine sounds including that of a typical V8 combustion engine, a racecar engine and two futuristic soundscapes named �Beam� and �Warp.� The volume of the sound is dependent on the momentary power output of the electric motor. ”
Ha ha… What will they think of next? 🙂
It could not be too quiet…………………even in Verano, some sounds are noticed…it is the lack of any squeaks, wind noise, and harshness that is so enjoyable…I am going to see how it goes soon when I drive the ATS base 2.5 🙂
I drove 2.5 ATS today….drove maybe 15 miles or so by myself…smooth ride and quiet…there is a definite and noticable engine “growl” I did not really care for but OK…engine shifts noticably and not as smooth as I thought it would be at all…..overall, a very nice car….I did not feel it to be all that cramped but, I am not tall. Seats were good and base radio was excellent…loved the dash and electonic controls..the blue backlighting is great. Quality and well put-together… No CD on base…salesman said that will soon be gone from all cars as will the nav….all that comes from phones connected to radio from now on!
Dan — good to hear you liked it. The growl and the shifting are the result of the sports-oriented nature of the car.
However, I can not wait for the day that CD players and built-in Nav systems are eradicated from cars entirely. They former is not needed at all, while the latter is so much inferior to the constantly-updating and much more user-friendly (and inexpensive) systems found on smartphones.
Alex, yes it was a fun time with ATS…really very similar to Verano…the engine and shifting are fine in both cars…just not used to that feel in a Cadillac. I will say the ride is still Cadiilac quality over railroad tracks and rough payment; as quiet as the Buick in most every way in town and on the road. I guess the salesman knows his stuff regarding the electonics…unlike others on the site who have said that Cadillac has old-school staff? I think miost people will like it…and as far as 2.5, I found it very peppy and more than sufficient in every way; I loved the precise steering and the ease of the turns! You were correct in every thing you have said 🙂