Car Stereo Buying Guide
Car audio fans had cause for celebration the day CD players moved from the home into the dashboard. Until that day, drivers were stuck with a choice between the radio, a cassette player, or (heaven forbid) eight-track cassettes.
Needless to say, the sound quality of those three options was pretty abysmal. CD brought digital quality out onto the open road. The same qualities that you appreciate at home are just as important in the car. However, the enhanced dynamic range is actually a problem. In the quiet of your home, the soft passages are clearly heard without any analog tape noise. In your car, these same soft passages can get lost amongst engine and road noise. Perhaps this is why cassettes are still around. However, look forward to the day that strands of cassette tape won’t litter the roadsides.
When CD changers were first introduced, they were almost exclusively magazine cartridge monsters that would only fit into the trunk of your car. Why are these considered so inconvenient? Well, imagine yourself on a long road trip with the trunk of your car packed to the brim, in the dark on the side of the road, oh, let’s add some rain too, trying to swap out a CD for the one you are just dying to hear. Not a pretty sight, but this style still remains popular, and the range of options has dramatically increased.
Today, there are a number of choices for CD changers. Trunk mounts are still popular, but they’ve added convenience features, like remote controls if your head unit doesn’t have changer controls. Some even use FM modulators to broadcast the signal to your FM tuner.
Other styles of CD changers can be mounted in a glove compartment or under the front seats. This makes it easy to swap out discs without having to stop the car. However, please let a passenger handle the discs while you keep your mind, eyes, and hands on the driving duties.
Even better, today there are some CD changers that fit right into the dashboard, using an elevator-style method of handling the CDs. You slip disc after disc into the single slot on the front of a standard 1-DIN unit, and the changer stacks them internally. This is by far the most convenient style changer available.
A typical car audio system consists of: the head unit, the wiring, and the speakers. The head unit refers to the actual body of the audio system which holds the tape and CD player as well as the radio receiver, along with all the control buttons and knobs. Wires connect the head unit to the car battery and to the speakers. Initially, the speakers used to be placed within the dashboard, with sound being emitted through vents provided for the same. The speakers may also be placed in the car doors, the roof, or in shelves at the rear of the vehicle. The layout of the speakers plays an important role in the quality of sound output, preventing jarring of the sound even at high volumes. The basic operation of the car audio system is similar to the working of a normal household stereo system.
1. How Car Audio Systems Function
A typical car audio system consists of: the head unit, the wiring, and the speakers. The head unit refers to the actual body of the audio system which holds the tape and CD player as well as the radio receiver, along with all the control buttons and knobs. Wires connect the head unit to the car battery and to the speakers. Initially, the speakers used to be placed within the dashboard, with sound being emitted through vents provided for the same. The speakers may also be placed in the car doors, the roof, or in shelves at the rear of the vehicle. The layout of the speakers plays an important role in the quality of sound output, preventing jarring of the sound even at high volumes. The basic operation of the car audio system is similar to the working of a normal household stereo system.
The head unit has a built-in amplifier which amplifies the input voltage and current, subsequently increasing the audio power output to the speakers. In order to ensure clear sound and also to prevent damage to the speakers, the power of the amplifier is always less than the power handling capability of the speakers. Large power emitting amplifiers have large gauge cables to transmit the increased voltage and current.
The speaker set generally includes a tweeter to transmit high frequency sounds, a midrange apparatus for median frequency output, and a woofer for low frequency sound waves. The speaker system incorporates the audio crossover technology, which entails the use of ‘electronic filters’ that separate different frequency bands of audio signals and send them to different components of the speaker set. Thus each speaker only receives input of audio frequencies that it is best capable of handling, generating superior quality sound. Subwoofers emit bass and sub bass sounds, which are more felt, than heard, by the listener.
In order to derive the best output from the audio system, in addition to its normal installation, certain architectural modifications may need to be carried out on the car’s interior. There is a chance that the metal body and shape of the car may result in jarring of the sound from the music system, which is often the case in confined spaces due to clashing of sound waves. This drawback can be minimized with the usage of ’sound deadening’ material which absorbs sound waves and also prevents excessive vibration of the metal parts of the vehicle. This is achieved through the use of rubber or asphalt-like material that is stuck in sheets in vulnerable areas of the car.
Some car audio systems offer CD changers built either into the head unit itself or placed at the rear of the vehicle, in the boot or the trunk.
Keep in mind though, video playback in your car has not been left behind. Some new systems have Digital Versatile Disc (DVD) players, enabling movie buffs to even watch movies. Some players have the Liquid Crystal Display (LCD) screens directly connected to the head unit, while others have the screens mounted in the front of the vehicle above the wind screen, or fixed to the rear face of the backrests of the front seats. It goes without saying that the DVD facility is meant only for passengers and the driver of the car should abstain from viewing the LCD screen to ensure a safer ride.
It should be noted that the audio system is powered entirely by the car battery and should not be used if the battery is running low or if power is needed for some other more urgent purposes. However, there are alternatives to resolve this issue. Extra alternators may be needed to be installed to enhance the output of the car’s electrical infrastructure. Another way of raising the power efficiency of the system is to install a deep cycle battery. This battery is more reliable as it is designed to release a sustained flow of current for a longer time as compared to a normal car battery that releases a greater amount of current for a shorter length of time. This kind of battery also discharges around 80 per cent of its total prior to recharging, improving performance. Implementation of the deep cycle battery, or an array of batteries, enables the audio system to work for prolonged periods without the vehicle engine running. Another alternative source of power for the audio system could be the usage of a capacitor, a device that stores electric charge by creating an electric field between two conductors.
2. Purchasing Criteria
With an ever-increasing number of companies offering a wide variety of options, it can be quite difficult deciding on which brand to go for. In order to facilitate your decision, listed below are some of the parameters you may want to look into when buying a car audio system
* Power Output: Depending on your tastes, you should decide on the wattage of the system. If you happen to be a rock fan, then a greater output with more powerful woofers would be applicable; whereas if you are a slow ballads aficionado or a classical instrumental buff, then power output could be traded in for sharper sound quality, enhancing the nuances of every note.
* RMS vs. PMPO: When checking out any music system, be it a car audio system or a home system, it is advisable to consider the RMS (Root Mean Square) output figure rather than the PMPO (Peak Music Power Output) figure. The RMS output measurement is a more realistic representation of the actual output as PMPO indicates the output under maximum load, which no system works under, as this can lower the life of the device drastically. The RMS value measures the output over a period of time across varied conditions.
* Satellite Radio Compatibility: Since a car audio system is being used while traveling, satellite radio support might be something to consider. This kind of radio receiver enables detection of signals transmitted from communication satellites. Thus, the car occupants can listen to a single channel irrespective of where they happen to be, as the signal’s transmission is not restricted to any particular radio station’s coverage.
* Compatibility with Home-Recorded CDs/MP3s: Some music systems do not read home-recorded CDs. Only pre-recorded CDs bought in music stores work with such players. This may be a handicap in the long run as many people nowadays tend to burn CDs at home, and also download MP3 music from the Internet, which are then written onto CDs. It would, hence, be very necessary for your car audio system to be able to read and play such CDs.
* Extra Connectors: Even if you intend to attach any accessories to the device, it would be a good idea to have external connectors or ‘Preouts’, into which accessories, such as extra amplifiers or equalizers can be connected.
* Speaker Properties: Speakers may be either: two-way or three-way. Two-way speakers have a tweeter, for high frequency audio waves and a woofer for low-range frequencies. Three-way speakers have an additional facility for transmission of mid-range frequencies, generating deeper and better sound quality, making these kinds of speakers a better bet. For us, it makes more sense to go in for speakers having much higher power potential than the amplifier. This fact has a second rationalization considering the chance that the user may add an additional amplifier at a later point of time.
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