Car amplifiers are a popular way to pump up the volume in your car. They deliver deep booming sounds and crisp clear tones across an entire wavelength of the sound spectrum. In some circles, your car is judged by what you have under the hood, but in this case they are talking about your engine. They want to know how many amps you have in your trunk.
There are many different types of car amplifiers. Most are measured by the wattage they can handle, and this ranges from small, 250-watt systems to 2500-watt systems or more. There are also classes of amps for different uses. Class A amps produce clear sound but run very hot. Class AB amps are more common and more efficient, and they also run cooler. Class D amps are more efficient, produce less heat and draw less current but some create distortion. Class T amps are a little more advanced, combining the best of features of AB and D class amps--clear sound and efficiency.
Car amplifiers produce sound for a car stereo. They are the power source and control station because they both draw current for power and control the speakers. Car amps can produce extremely loud but clear sound through the signals they send to the speaker boxes. Combined with the right subwoofers (bass) and tweeters (treble), they can be extremely loud or produce very fine sound.
Car amps have a capacitor unit that controls the power flow from the car. This also distributes the power to the speakers. They have a few of the same features as a stereo amplifier, including power handling, which is measured by the wattage rating, impedance, subsonic cut offs and more. You can also bridge amps to produce a more powerful sound through one speaker. Many have multiple channels for several speakers.