Basic knowledge of car audio modification

If you want to modify your beloved car into a compartment, you need to understand the source of the noise of your car, the source of the noise felt while driving, and the degree of impact, and then choose a modification plan according to your needs.

    Sources of car noise:

    1. Mechanical noise from the vehicle itself;

    2. Road noise caused by friction between tires and the ground;

    3. Wind noise caused by high-speed driving;

    4. Mixed noise from external parties.

    Construction of system sound insulation engineering

    The sound insulation of the system is completed through three steps: vibration reduction, noise reduction, and sealing. The doors, trunk, chassis, hood, and roof are all places where air friction noise is easily generated, and most of the noise is transmitted into the car through the car's suspension system, chassis, trunk, and doors. Therefore, the most basic sound insulation project cannot ignore the doors and trunk. For the noise of the engine, if the engine itself does not have excellent stability and quietness, and you do not need the acceleration roar that car enthusiasts desire, it is recommended that you stick a layer of film under the hood - B-TOP hood special film, which can absorb and consume a lot of engine noise, while suppressing the vibration of the hood and blocking the heat from the engine, with an efficiency of 97%, and protecting the paint surface from damage due to long-term high temperature; in winter or in cold areas, this film can also play a role in heat preservation to protect the engine compartment from freezing and cracking. Car owners need to pay attention to the fact that all sound insulation materials must meet the relevant fire protection grade requirements to ensure vehicle safety and reduce vehicle weight.

    Improved audio listening experience

    In order to improve the sound effect, some shops have special speaker kits and a series of measures and optional accessories to improve the bass in the car. Installing such facilities can effectively improve the sound distortion caused by the resonance of the speaker panel and greatly increase the sound pressure level, especially to meet the needs of professional audio enthusiasts, so that you can immerse yourself in the enjoyment of pure music in an environment without interference.

    Acoustics Tips

    Sound is produced by periodic or non-periodic vibration of a sound source.

    The physics of sound

    The volume of sound is related to "sound pressure"; the sharpness of sound is related to the pitch of "audio"; the pleasantness of sound is related to the harmony of "tone". Sound is a kind of energy and a wave. After it is emitted, it must be released to the surroundings. The propagation of sound is through the medium in the form of vibration. The noise in the car is transmitted by resonance with the car body, which is called "structure-borne noise".

    From the perspective of environmental protection, noise refers to those sounds that are unwanted, disgusting, or obstructive to human life and work. Noise not only has its objective physical characteristics, but also depends on the evaluation of subjective feelings. For example, when listening to music, pleasant singing is not noise, but in the classroom where the teacher is lecturing, high-pitched music can only be regarded as noise.

    Sound pressure

    Sound can propagate in the air because a vibrating object causes a change in the local pressure of the surrounding air through vibration. This pressure change causes a local density change in the surrounding air. The local density change causes a change in the air pressure in more distant parts. This process continues to propagate, transmitting the pressure change to more distant parts, thus causing the propagation of sound.

    Sound frequency

The frequency of sound is referred to as audio frequency. The number of times a vibrating object vibrates per second is the vibration frequency of the object, and the unit of frequency is Hertz. Generally speaking, the vibration frequency of sound waves that humans can hear is between 20 Hz and 20,000 Hz. The source of sound waves is called the sound source. Below 20 Hz and above 20,000 Hz belong to the range of infrasound and ultrasound, respectively, which cannot be heard by the human ear. Within the range of sound waves, as the frequency increases, the pitch changes from low to high, but the sensitivity of the human ear is not consistent in different frequency bands. Generally speaking, when the audio frequency is below 1000 Hz, as the frequency decreases, the hearing will gradually become dull. Therefore, the human ear is more tolerant of low-frequency noise, but is more sensitive to high-frequency noise and has poor tolerance. If you live in a high-frequency loud noise environment for a long time, it will cause partial or severe hearing loss in the ears.

    The dangers of car noise

    Surveys show that motor vehicle noise accounts for 85% of urban noise. People who are exposed to noise for a long time will experience tinnitus, dreaminess, panic and irritability, or directly cause hearing loss or even deafness. According to incomplete statistics, traffic accidents indirectly caused by vehicle noise account for 60% of all traffic accidents.

    Sound insulation materials

    The materials used in automobile sound insulation and noise reduction projects vary according to the different installation designs. B-TOP series of sound insulation products include shock-absorbing sound insulation materials, sound-absorbing materials, aluminum film-coated heat insulation, sound insulation and sound absorption materials, etc.

    Bituo series of shock-absorbing and sound-insulating materials: mainly used to suppress the transmission of noise and strengthen the body steel plate;

    Bituo series foam rubber sound-absorbing materials: have the ability to convert sound waves into heat energy, and can achieve the best sound absorption effect;

    Bito hood covered with aluminum film heat insulation, sound insulation and sound absorbing material: suitable for use in the car engine compartment, with excellent sound absorption effect, and can reflect up to 97% of the heat, reduce the heat transferred to the engine cover, and extend the service life of the paint surface.

    Sound insulation engineering parts

    The characteristics of different types of car noise and the sources of noise in various parts of a single car are different. Among them, engine noise accounts for the largest proportion. By controlling the vibration and sealing of the engine cover, fire wall, skirt walls on both sides and fenders, the noise in the engine compartment can be effectively controlled and reduced, and the engine noise transmitted to the cab can be reduced. When the vehicle is running at high speed on a good straight road, the high-speed noise of the vehicle becomes another major noise source. Among them, the trunk is a big noise source, because it is a large cavity inside, which will produce a lot of resonance. Therefore, the trunk cannot be ignored when installing noise reduction equipment. The aerodynamic performance of the vehicle usually affects the friction noise of the vehicle. The main part that is usually prone to wind noise is the door. The measures taken for the door are nothing more than installing shock-absorbing materials and sound-absorbing materials in the door, and strengthening the sealing of the door.

    The impact of sound insulation on the vehicle

    Generally speaking, the sound insulation project does not require changes to the body structure, power system, and electrical oil and gas lines, so car owners do not have to worry too much. However, it is recommended that car owners choose a store with complete facilities for modification. Because the sound insulation construction must be carried out in a sealed, bright, and clean workshop, by installation technicians who have received strict professional training, and during the construction process, it is necessary to strictly follow the process flow to ensure that the body and interior parts will not be damaged.

    Misunderstandings of sound insulation engineering

    Many car owners think that car sound insulation is a very simple job, and they only need to stick or add some materials such as felt, asbestos, sponge, etc. in the car to achieve the sound insulation effect. In fact, these materials have little effect on the improvement of the sound of the vehicle. In fact, these materials are not environmentally friendly and have poor fire retardancy, which will cause pollution and pose a great safety hazard for future vehicle use.

    In addition, some car owners feel that their cars are noisy because the car itself has faults, such as irregular tire wear, suspension or chassis damage, and abnormal engine noise. These problems cannot be solved by sound insulation alone. Professional technicians will find the problem for you and recommend that you repair it before sound insulation.