How Are Cars Set Up For Music And Phone Calls?

There are many ways to equip a car with high-quality audio technology today. For example, did you know that audio is calibrated differently for playback than for phone calls? “A car’s sound system is defined by the car’s class. A concept and strategy are then developed and used when putting together a set of speakers. They differ, for example, depending on whether an external amplifier is envisaged,” says Vlastimil Navrátil, coordinator of the reception and sound department at ŠKODA Technical Development.

The basic version consists of a radio and speakers. An incomparably better experience is offered by “sound systems”, which deliver better sound through a higher number of speakers. ŠKODA offers two types: the simpler one found in lower-range models is called ŠKODA Sound and is developed by the carmaker itself. For the OCTAVIA, SUPERB, SUVs and electric cars, there is the Canton sound system. Developed together with a prestigious German manufacturer, Canton offers a three-band system for the front and a two-band system for the rear doors, and also includes a midrange speaker and a subwoofer.

A fight for every millimetre

The placement of the speakers is crucial for a good interior sound system. This is literally a matter of millimetres. “Our cars have an airy interior, so the door panels, for example, are made as thin as possible. That means there is not much space for various components – there are window adjustment mechanisms, door controllers and the requirement for space to store a plastic bottle. And then we need to fit speakers in there,” says Petr Rakušan, who is responsible for car speakers.

The engineers try to ensure that the speaker is as close as possible to the mesh cover and does not interfere with the other “door equipment”. The stiffness of the sheet metal also plays an important role, which is why the speakers cannot be placed just anywhere. The woofer in particular needs the stiffest possible space, which is why it is placed in the bottom corner of the door near the hinge, so that the audio output does not leak into other parts. The midrange speaker is mounted directly on the door panel, i.e. on the plastic. “This is where it’s hard to find the best position. Here, too, we do a lot of tinkering to find the best placement and angle for the car’s occupants,” reveals Navrátil.

Cooperation and the struggle for position

The number of speakers for the various audio system levels is fixed. So you can choose a basic system for the front only or for all doors, or one of two sound systems. The top-of-the-range Canton system thus offers eleven speakers and a subwoofer with an output of two hundred watts. Depending on the car model, the total output of this system is up to 675 watts. In general, it is fair to say that parameters such as the number of speakers and music audio output are the same for all models the system is fitted in, with some minor differences.

Technology and the human ear

Now that we have the hardware sorted out, we need to get everything working properly. The first step is to take static measurements. This testing takes place in ideal conditions in the laboratory: the silence is not disturbed by outside noise. “We measure the car’s frequency characteristics to see how the various parameters are affected by the speaker grille cover or the placement of the speaker in the doors or on the dashboard. We try to achieve the most balanced sound character, i.e. the flattest curve possible. In other words, the input is the same as the output. So we don’t add bass, midrange, etc. The goal is to make the recording sound as identical as possible as the sound engineer mixed it in the studio,” explains Bambásek.

What does the future hold?

Given that, sooner or later, we will enter the age of Level 4 and Level 5 autonomous driving, when the occupants will want to have fun and not be disturbed by outside noise, it stands to reason that more and more systems will be developed to suppress outside noise. Some of the source information comes from external microphones, but noise from the chassis, wheel arches and so on also needs to be processed. This technology already exists, but it is still a very expensive solution that most car manufacturers cannot afford. So the future lies in finding a technically suitable and workable solution at a reasonable price.

Finally, one more insight into the future from the reception and sound team: imagine that every passenger in the car will be able to play their own sound without disturbing each other. A kind of zone will be created: one person can talk on the phone, another can listen to an audiobook and another can listen to Mozart or AC/DC. And they’ll have no problems sharing the same interior. Research and development is already underway and similar solutions do exist, but they are still in their infancy. The vision is nonetheless enticing.