If I ask you how you imagine the sound system of a car, it is safest to think of a player with several multimedia supports and speakers. Nothing else. You can think that it is one of the simplest parts of a vehicle, but a visit to the technical center that SEAT has in Martorell has shown us just the opposite.
The audio system of a car may not be the most complicated to create, but of course its conception is much more complex than can be believed at present. The SEAT engineers have explained everything that is taken into account when adding the speakers taking advantage of the presentation of the Beats series of their Ibiza and Arona models.
When the speakers in a car were underrated
At the beginning, in the 60s, the installation of audio in cars was a luxury. And it was something as simple as placing a radio on the front console with two side speakers , without taking into account any factor on the sound quality. If you were lucky and you picked up a station, you could listen to it. That was the end of everything.
The music stored on a stand came with the quadraphonic tapes, and in the 80’s the audio cassettes that older millennials remember in many cars of our childhood. The speakers went from two front seats to two or even four at the doors. There was more sound quality, but it was more about improving the support and the radio stations than the speakers. There was no place for optimizations: it was more important to place the airbag and take the trouble to optimize the sound was seen as something completely secondary and unnecessary.
We keep moving forward in time and then we come to digital audio. The quality improves a lot, but we reach a ‘top’ in which the quality of the music is already measured in Kb per second. On the support side, there is no longer going to be an improvement as great as it has been up to now. At that point, the engineers had to look for other ways to continue improving the audio quality of a car. And the answer was found on the speakers .
In the same way that the builders of a cinema or concert hall look very well at the position, size or orientation of the speakers, engineers could begin to take these factors into account with the loudspeakers of a car. Not only in the quality of the speaker itself, but where you placed it, how you placed it and how you modified your equalizer to make it sound better.
From here, according to the engineer of SEAT Adrián Mateo tells us, the studies to improve the quality of the sound in the interior of the cars happened to have a lot more importance. Improving this aspect of the cars went from being “unnecessary and secondary” to being something much more important, and the engineers of other parts of the vehicle stopped demeaning it.
The result is that we have gone from radios with front speakers without any adjustment in the 60’s to systems of up to 10 speakers carefully tuned and distributed to offer the best possible quality in a vehicle.
Expect shipments of a month to be able to do everything in the factory
Adrián Mateo also tells us how the process of tuning an audio system for the car itself has gone from being extremely tedious to relatively comfortable. As we mentioned before, at the beginning the rest of the engineers had the priority: they placed the main components of the car and the part of the sound ‘ that gets where you can ‘.
That was improving as the audio quality of a car was more and more important, although the technology of a few years ago made the process very heavy. As a sound engineer you modified the equalization of the speakers, yes, but there was a time when it was the manufacturer of the sound system that had to apply the parameters .
So the engineers calculated those parameters, they sent them to the manufacturer, the manufacturer sent the speakers tuned with those parameters, the engineers did not like the way it sounded, re-tuned, re-sent … maybe it took a whole month to receive tuned speakers , so you can imagine how long it took to properly modify the sound of a car’s speakers in the last century.
Fortunately, that has changed and now technological advances have allowed automakers to rely much less on audio systems providers. In the case of SEAT, a system is tested and tuned within a properly isolated sound studio, digitally, with computers and with all the expert personnel present in the test.
The chamber in which all the tests are done is completely anechoic, with the walls absorbing all the sound and preventing it from bouncing. When a car is parked inside the room, high-sensitivity microphones are used to record the sound quality of the speakers, to a point where the effects of the same dust floating inside the vehicle can be determined. The same thing happens with humidity, and from SEAT they describe that they have instruments in other rooms to be able to calculate the effects of it.
However, the process (at least in the case of SEAT) lasts about three years. It begins with tests in those rooms and studios, with the own speakers, and ends with the tests of the system in full conduction to verify if everything has gone well.
Position, orientation and materials: everything matters
There are quite a few factors when it comes to tuning the sound system of a car. For starters, we are talking about a closed environment and much smaller than a room, a movie theater or a theater. And that closed environment will have sound from outside if we are moving, of course.
The position of the loudspeakers is important: when placing in the doors it is necessary to bear in mind that they can be covered by obstacles that bounce the sound like the seats of the car (that can move when reclining) or our own body. You also have to take into account the external grid that protects each speaker, which will inevitably change the quality of the sound.
Something very important: we know exactly where the people in the car are going to be . It is something that we can not know with such precision in other cases of use. Adrián mentions us Apple’s HomePod as an example of good step in this aspect, since this speaker modifies its equalization depending on the place of the room in which it is.
In the car that can translate into modifying the balance of the speakers depending on whether the driver is listening to them or there are more people in the car. The most common is to add a delay in the signal of some speakers so that the vocal part of a song sounds more or less in certain areas of the booth. The most modern audio systems allow the user to modify this point.
But still, and no matter how hard you try, it ‘s impossible to achieve a studio quality in a car’s audio system. The materials it is made of, like crystals, prevent it. Until the fixing of the insulation of the door affect the bass. The engineers are very clear that although there have been great steps in the sound on board a car, there are quality levels that simply can not be achieved.
To improve the audio quality of a car is a job that has improved a lot during the last years, but due to the very nature of the car it will never end . The materials, the shape, the loudspeakers themselves … you have to make adjustments for each model that is manufactured, and any advance can change everything. Fortunately, it is becoming easier to apply all the changes.