How we test: Noise

If the sound of silence is one of your top priorities when buying a car, you should know that we test for noise on each and every model that we buy.

Our "noise" score combines the weighted averages of objective and subjective measurements. The objective measurement is taken with a sound analyzer placed in the front passenger seat with the microphone at approximately ear level. We also measure noise levels at 40 mph on course surfaces, 70 mph on smooth surfaces, and at wide-open throttle from zero to 60 mph. Subjectively, noise level and quality is judged by five engineers driving the car over a defined "One-Day Trip" road course.

It would seem that rating noise would be fairly straightforward, but it isn't so simple. For example, while the sound analyzers tells us how loud the interior noise is, we also need to rely on the subjective ratings of our drivers to tell us the quality of noise. Is the sound obnoxious? Sporty and fitting in with the character of the car? Or serene and well isolated? The subjective ratings also help us determine the source of the noise. Is it wind noise past the mirrors? Road noise permeating the cabin? Although we test on a variety of road surfaces and speeds, the noise experience can be dependent on the road, vehicle, speed, and general ambient conditions. If you're looking for a quiet car or truck, read our test reports; but also take any model you're considering for an extended test ride, preferably over roads you often drive on to be sure it meets your standards.   

It comes at no surprise that some of the quietest cars are in the near-luxury or luxury classes. Of the 128 cars and trucks tested from the 2005 and 2006 (thus far) model years, only five received an excellent noise rating. These are the Audi A6, Cadillac DTS, Lexus GS300 and RX Hybrid, and the Toyota Avalon. To achieve this level of quietness, the interior has to be well isolated from road and wind noise and have subdued powertrain noise levels. As-tested prices range from about $33,000 for the Avalon XLS to around $52,000 for the GS300 AWD.   

In general, most family sedans, minivans, and midsized and large SUVs have very good noise isolation, including CR Top Picks like the Honda Accord, Acura TL, Infiniti M35, Honda Odyssey, Honda Ridgeline, Toyota Highlander Hybrid and Toyota Prius. Smaller vehicles, such as the Honda Civic and Subaru Forester (also Top Picks), score a step below for noise isolation. The noisiest cars we've recently tested include the Lotus Elise and Pontiac Solstice. These two sporty cars rated Poor for noise isolation and were even noisy enough to make listening to the radio a challenge.

--Gene Petersen