Austin, Texas: Searching for the "perfect" automotive sound idea is nothing new.
Mercedes-Benz was bragging about its signature door "thunk" six years ago. Porsche manufactured a particular sound piped into its cabin to augment the otherwise near-silent ride of the electric Taycan sedan. The deep rumble of the Lamborghini Aventador can be identified from blocks away.
But atop the pinnacle of luxury with machines that can cost $300,000 or more - twice the price of an average home in the US - crafting the perfect sound experience is of particular concern. The entrepreneurs and business owners and scions who own Rolls-Royces operate in extremely complex worlds, says Richard Carter, the brand's communications director, so they value in their cars more than anything a sense of calm and wellness.
Still, there is such a thing as too quiet. The ultimate luxury space must strike a balance between closing off the chaos of the outside world, in order to create a serene cocoon, and being so shut off, it starts to feel like a tomb.
Not a peep
In the new, second-generation Rolls-Royce Ghost, early test audiences during its five years of development reported that the car felt so quiet it was disorienting. "Bordering on nausea," reports the car's lead engineer, Jon Simms.
It turns out that altering the previous Ghost's frame from steel to aluminum (which carries less sound than its heavier predecessor), insulating the bulkhead of the car in a double-soundproofed, sound-deadening skin, and filling the rest of the roof, trunk, and floor with 220 pounds of sound-absorbing materials worked a little too well. So did smoothing the insides of the air-conditioning ducts, double-glazing side windows with a clear composite center sheet, and lining the tires with lightweight foam.
So Rolls-Royce engineers had to do something counterintuitive: Make the ride noisier. The auditory goal throughout was two-fold, Simms said. First, the Ghost cabin needed to remain quiet enough to whisper a conversation at speeds up to 80 mph.
Second, the Ghost needed to lose any annoying squeaks, clicks, hums, or thuds as the car drives - quiet yet annoying sounds "like a mosquito buzzing around your head in an otherwise silent room," says Simms. And not giving passengers motion sickness is a given.
Finding a pitch
To help offset the obliterating sense of silence, Simms and his team developed a soft undertone to pipe into the cabin. They tuned the rear seat frames and components in the trunk to a vibrate at a specific low frequency, as musicians might tune instruments to a particular pitch.
They recalibrated the 563-horsepower engine to downplay its rumbly noise, and avoided aggressive drive modes such as track or sport, which would rev it louder. They rearranged the four layers of sound insulation inside the doors to help pad out dead pockets of air. They even eased up on the heavily padded headliner.
I experienced the resulting whisper while test-driving the Ghost last month. The instant the doors closed with a feather-light thud, it felt as if I had stepped into a spa. As I drove through the rolling Texas hills, I felt a deep sense of stillness and purity, even inside a speeding machine powered by fossil fuels.
The balanced tones coming into the cabin via the trunk suggested what one might imagine David Foster's studio sounds like when he records with Andrea Bocelli - that moment when the last note lingers in the air, and the hum of energy dissipates.
Alexandra Park Souto, a Wraith, Ghost, and Cullinan owner who resides primarily in Austin, may say it better. Noting that she chose to drive her newborn son home from the hospital in the family Rolls for the same reason, "I needed to be in a space where I felt protected and safe," she says.
For an automaker selling the ultimate in luxury, call that the perfect pitch.