This is a post from our guest writer Susan Miller, an audio expert, from Audiogearhq.com.
Anyone who frequently drives knows the problem: the engine roars, the wind rushes – the passenger and radio are hard to understand, and after a few hours of driving the ears are half deaf. For a long time, car manufacturers have been neglecting interior noise. However, they are now making some efforts to ensure that the car is quiet while on the move.
Aerodynamics are decisive for the noise level
In addition to the intake and exhaust noise of the engine, Eggers, from TUV Hannover, names the rolling noise of the tires as the main source of noise in the car. “In the interior, the aerodynamic properties are also decisive,” says the expert Eggers. Wind noise was particularly noticeable at high speeds. But a lot has been done in this respect.
One example is VW. During the generation change from Golf V to Golf VI, the manufacturer paid special attention to the topic of noise in the interior. An insulating foil in the windscreen and new seals for the doors and side windows are intended to reduce driving noise. In addition, the engine and interior have been better soundproofed from each other. The change in injection technology from the relatively loud pump/nozzle process to the quieter common rail process means that the diesel engines have a quieter engine noise, says VW spokesman Christian Buhlmann in Wolfsburg.
Active noise reduction
The developers wanted to reduce the noise of the airstream by providing the Golf with aerodynamic exterior mirrors. According to VW, these measures also make the new Golf “the quietest Golf in the series’ history”. Compared to its predecessor, it is 5 decibels quieter when measuring the interior, says Buhlmann.
Honda has taken a different approach with the revised Legend. In order to reduce the noise level in the interior of the luxury saloon, the Japanese manufacturer uses an “active noise reduction” system. According to Honda Motor Europe in Offenbach, the system filters out low-frequency noises by reproducing the opposing sound waves via the audio system and neutralizes them. In addition, there is a sound-absorbing windscreen and improved chassis bushings.
Test drive when buying a new car
According to ADAC expert Arnulf Thiemel, the “noise cancelling” method, which eliminates sound waves by means of a counterpart, is still the exception in series production. The most common processes are the insulation of windows and gaskets, the use of tires with low rolling noise and the use of special wheel arch linings.
To avoid any nasty surprises with regard to noise, Arnulf Thiemel recommends driving the car with the desired engine before buying it. There is another thing to keep in mind: “The same engine can sound completely different in the other car”.