World without voice and sound is beyond imagination. The various sound produced makes a lively life. Sounds are used in various forms that make musical notes and sound from the instruments. After the invention of radio people began to listen to various radio programs including entertainment program and news. With introduction of several transmission stations different type of radio programs were stated to be broadcasted. During the period of 1930’s music lovers began to adapt domestic audio equipment in their cars. Later on with the invention of audio systems people started using personal audio systems that recorded and played different programs. With the technological development radio systems began to be used in the vehicles. In 1930s the first fitted car radio was introduced by Galvin Manufacturing Corporation. During 1950’s-1970’s car radios with tune in function became popular. In the year 1983 the car audio amplifiers were introduced by Steven Mantz as Hi Fonics Zeus.
Earlier the home audio speakers were installed in the cars. In order for to adapt these home audio speakers to the temperature variations different components and different manufacturing techniques were used. During the 1980s compact discs were introduced that replaced the magnetic tape systems that were used as audio cassettes in audio systems. Later on stereo systems began to be the most widely used in automobiles particularly in the cars as it gave more clarity sounds instead of the mono audio systems.
In 1990’s technological revolutions began in the audio system technology. The CDs were widely used in the cars. The major drawback of CDs was that they are subject to vibration and temperature of moving vehicle that affected the sound quality. Many innovations including passive and active digital skip protection improved the vibration and temperature while playing and reduced the risk of shock and vibration.
There are several components included in the car stereo or audio system. The stock system in a vehicle includes stereo sound head unit, speakers, CD player. These components are installed in the interior panels and input jack for external play back devices including smart phones. The main component is the head unit. It is the primary control device in an audio system. This need to be fixed in the dash panel of the vehicle between the passenger and the driver. It is placed in certain vehicles vertically between the passenger and the driver. The standard size of the head units are technically termed as DIN. There are two types of DIN single and double DIN. The head unit is a multipurpose device with a group of devices with different functions. CD player, DVD player, satellite radio, HD radio, USB flash memory, a portable hard disc drive and radio receiver and tuner for receiving and tuning FM radio transmissions. The stereo speakers in cars are like the loudspeakers. Marine speakers have the special feature of corrosion resistance. The materials used are with expensive and rare components that are adaptable for mobile use. In modern cars speakers are installed in front deck or dash of the car, the rear deck the kick panel that is located in the foot well below the A- pillar. Even though the headsets have an inbuilt amplifier some time as an additional feature external amplifiers are also installed in the vehicle.
One of the drawbacks of the car stereos is the legal restriction in the production of sound in the vehicle. There are strict legal restrictions regarding the production of sound that the stereo sound shouldn’t exceed any sound limit that makes noise pollution. The loud stereo systems create low frequency of sound resulting in bass voices that exceeds the audible limit.
The relaxing and refreshing music from the stereo systems is a good factor to have a car drive but the control over sound produced form the system need to be in concern while driving.