Car Amplifiers

If you're sick and tired of driving around with a car stereo that sounds as if the music is coming from the bottom of a tuna fish can, then what you need is one of the many car amplifiers available today. A quality car amplifier can turn your normally meek stereo speakers into a set of pulse-pounding, music-making machines.

An amplifier is installed between the main stereo unit and the speakers. Its purpose is to boost the signal that is being put out by the stereo unit so that the sound being emitted by the speakers is the best it can be. It accomplishes this through a series of transistors, resistors, conductors, rectifiers and other delicate electronics.

The main problem that most people find themselves facing with car amplifiers is choosing the right one for their vehicles. There are a large number of different car amplifiers available, and when it comes to getting the best music quality in your car or truck, matching the right amplifier to your system is important. In this buyer's guide, we will look at the different types of car amplifiers available and explain their differences so that you can be more prepared when making your purchase. We'll also provide some explanation of certain words and terms that are important to know when looking for your ideal amplifier.

Mono amplifiers-A mono car amplifier is a single-channel amp that's best suited for low-frequency applications. With this type of amplifier, each of the connected speakers gets the same audio signal; there is no left-right stereo separation.

2-channel amplifiers-A 2-channel amplifier powers two speakers in a left-right configuration. While this is a common type of car amplifier used in many stock audio systems, it does not produce the best sound quality, as the speakers powered by the amp are typically installed on the door panels. It is, however, a cost-effective way of boosting your car's sound quality if you're on a budget. Two-channel amplifiers are usually small and therefore can be installed under a seat or somewhere else inconspicuous.

4-channel amplifiers-A 4-channel amplifier powers four separate speakers in a typical 2-left and 2-right configuration. Because four speakers are being powered, a 4-channel amp is larger and requires more wattage than mono or 2-channel amps. A 4-channel amplifier is generally installed in the trunk or rear compartment of the vehicle, and it provides a versatile means of maxing out your car's audio performance.

5-channel amplifiers-With a 5-channel amplifier, five speakers can be powered independently, thereby producing excellent sound reproduction within your vehicle. This type of amp allows you to install the speakers in a variety of patterns to ensure the best possible sound for your vehicle's acoustics. For example, two speakers in the front dash can be powered; two in the rear of the car can be powered, and a fifth powered speaker or subwoofer in the kick-panel can be powered as well.

6-channel amplifiers-A 6-channel amplifier produces premium sound landscapes within a vehicle because up to six individual speakers (including the subwoofer) are being powered separately. While offering the best flexibility and sound reproduction, 6-channel amplifiers are understandably the most expensive, the largest and most complicated to install.

Before You Buy

Before you purchase a car amplifier, you will need to know two important things about your vehicle's sound system: its RMS (root means square) power and peak power.

Each car speaker and subwoofer has an RMS power rating. This is the amount of continuous power (measured in watts) a speaker can handle before it is damaged. This is important to know because if a speaker is driven by too much power, it will overheat to the point of damage.

Peak power is the highest level of wattage an amplifier can produce. While both figures are important, the RMS power rating is more indicative of an amp's long-term performance, and it's the number you should consider most when matching an amp to your vehicle's audio system.

Car Amplifier Glossary

There are a number of terms used to describe the features and capabilities of car amplifiers, and many of them may be confusing. Included here are a few terms that will help you get a better understanding of what to look for in a car amplifier.

Bridging-Bridging is when two channels on the amplifier are connected to a single speaker source, like a subwoofer, to increase the power level to that speaker. Not all amplifiers are bridgeable, so always check the manufacturer's instructions before bridging.

Bass boost-Some car amplifiers feature variable bass boost circuitry that allows the user to customize the level of low frequency output in an audio system.

Crossovers-A crossover features both high- and low-pass filters that control which sound frequencies are being amplified. For instance, a low-pass filter will prevent high frequencies from being delivered to the subwoofer, and a high-pass filter keeps the low bass frequencies from being sent to the smaller speakers. These types of amplifiers will either be selectable or continuously variable. Selectable ones allow the user to choose from among a number of preset crossover configurations, whereas continuously variable models allow the crossover filtration to be adjusted anywhere along the line.

Ohm-Ohms is the unit of measurement for resistance, or impedance. Speakers are usually rated in ohms, typically between 2 and 8 ohms. This is important to know, as a speaker rated at 8 ohms requires twice as much wattage to produce sound at the same level as a 4-ohm speaker.

Pre-amp outputs-A pre-amp output allows you to pass the pre-amp signal to other amplifiers if you are using a multi-amp setup. This eliminates the need to run long patch cords between each amp and the receiver.

Signal-to-noise ratio (dB)-Rated in decibels (dB), the signal-to-noise ratio rates the level of the music when compared to the level of background noise. When reading the signal-to-noise ratio, the higher the dB, the lesser the background noise.

Subsonic filter-On the audio spectrum, there are bass levels that are so low that the human ear cannot hear them. A subsonic filter eliminates those frequencies from the speakers, which helps to make your entire audio system more efficient.

Total harmonic distortion-Total harmonic distortion (THD) is used to measure the amount of change a signal undergoes when being amplified. A lower number indicates a more accurate amplifier.