Technological progress makes the engines quieter and more silent: but this does not appeal to drivers, so manufacturers say “acoustic falsification”.
Many automakers in recent years have begun to equip their own models – particularly sporting ones – with systems that forcefully increase the engine volume inside the passenger compartment to make the driving experience more engaging; The technical solutions range from in-car directional tubes that have the sole task of amplifying and directing the driving sounds from the engine, to real dedicated speakers that reproduce pre-recorded audio files.
Choosing to resort to artificial systems to bring mechanical noise to the driver’s ears is the paradoxical consequence of technical evolution, which has made the engines ever quieter and more efficient cars chassis in isolating the cockpit from the sounds coming from from the outside. The need to adapt to the limits of environmental and acoustic pollution forces manufacturers to develop increasingly refined engines and exhaust systems, which, in addition to limiting polluting emissions,
Convinced that the sound of the engine is a fundamental element of the “personality” of a car, enthusiasts have come up in big discussions and protests against these artificial devices, guilty of their perception of misleading consumers. The clerics of the purists have their good reasons: amongst the car’s distinctive features, in fact, there is always the acoustic one, and you do not have to be enthusiastic in the industry to recognize “a ear” that a Ferrari sounds differently Compared to a truck or a utility vehicle. These differences stem from the movements of the mechanical parts that make up the engine, simplified in the typical four suction, compression, burst and discharge times.
In a very (very) summary, a blast engine works like this:
1. The outside air and the fuel of the tank are placed inside the cylinder;
2. The piston, which moves vertically inside the cylinder, rises and compresses the air and fuel until the blast of their mixture (spontaneous due to the high temperatures in the diesel, driven by the ignition of the spark plugs In petrol engines);
3. The mixture of air and fuel explodes and the energy generated by the explosion pushes the piston down;
4. The piston comes to the bottom of its run and goes out pushing the exhaust gases out of the cylinder which are the combustion residue.
All four of these phases together produce the sound of the engine, but each of them has a specific stamp that may vary according to configuration: the different shape and length of the air suction ducts, the number, burst order, The size and layout of the cylinders (eg three, four, six, eight, twelve cylinders arranged in line, opposite or V), the type of fuel used (gasoline or diesel) and the shape and length of the discharge contribute to determining Noise of each engine. Some stamps are so characteristic that they have become part of the collective imagination over time; Even those who are not passionate, will recognize below the baritone gurgling of the typical V8 Americans and the acute scream of Formula 1 engines used in the past years.
Since our brain (or that of motorcycle enthusiasts) instinctively coincides power with volume and driving satisfaction with certain sounds, car manufacturers have always tried to make the noise of their own sports motors pleasant and engaging. Lexus, for example, to optimize the LFA supercar presented in 2010, even collaborated with the Yamaha Center for Advanced Sound Technologies engineers – part of the stereo equipment and musical instruments division – to reach the pilot’s ears each A significant and rewarding acoustic detail of the V10 gasoline engine.
The practice of “tuning” engines like musical instruments takes time and resources, and can not always be carried forward: for this reason, some homes have decided to solve the problem by using some trick. Among them is the Sound Symposer mounted on the latest version of the Porsche 911, a mechanical device that – by means of a hose, diaphragm, and a push-button valve – has the only function of directing the sound of the air enters In the engine to the passenger compartment. The 911 driver may decide to ride with a discreet backdrop, or press the “Sport” button on the central tunnel and trigger a symphony of metallic clangs, bumps, puffs, and creeps when the throttle is released.
The next step in this “brum brum” counterfeiting process for the benefit of sensory pleasure is that adopted by, for example, the BMW German carmaker, who in developing his latest high performance M5 F10 series car salon realized that the chassis isolated Far too much noise from the 560 hp engine. To offer the driver greater involvement and help him to change “ear-to-head” driving, the BMW engineers have developed a system that reproduces the engine’s external sound through the stereo speakers. Of course, some “natural” mechanical noise coming under the bonnet arrives inside the car, but they are accompanied by a recorded background that varies in tone and volume according to the engine speed and the throttle pressure,
BMW similar devices have been adopted by many other brands: the latest generation Volkswagen Golf GTI, the dedicated speaker that reproduces engine recorded sound is called “Soundaktor”, while the video below shows the operation of the electronic synthesizer Edge of the new Ford Mustang EcoBoost.
Silencing an engine (which in itself would make a lot of noise) then having to get it back through electronic devices seems pretty absurd, but builders justify claiming that the active sound control – that is, the noise selection made to send in the passenger compartment only those Pleasant – guarantees a better perception of driving experience. In this sense, the acoustics are treated as an endowment of the car, which must therefore meet certain quality standards, as well as the finishes or the leather of the seats.
The maximum degree of acoustic falsification achieved to date in the car world – albeit wished and openly declared as such – is probably the one of Renault Clio, which offers through its multimedia system R-Link the choice of six different noise engine. The “sound customization” function (as defined by the same manufacturer) is called R-Sound Effect and allows you to drive your own quiet French utilitarian, accompanied, inter alia by the sound of a vintage car or a motorcycle of the MotoGP.