Speakers and the head unit are the most important components of a car audio system. Think of the head unit as the brain: it dictates what kind of sound is produced. The speakers are like the vocal cords; whether the sound is sweet and pleasant depends entirely on their "voice."
Speakers, commonly known as horns, function to convert audio electrical signals into acoustic signals and radiate them into the surrounding air. Cone-shaped designs are most common for car speakers. This is because, given the limited installation space inside a car, a cone design maximizes the effective area of the diaphragm, which determines the speaker's low-frequency response. In other words, the cone design can enhance bass effects without adding a heavy subwoofer.
By application, speakers can be classified into full-range, low-frequency, mid-frequency, and high-frequency types. They can also be categorized by energy conversion form into electrodynamic, electromagnetic, piezoelectric, electrostatic, and flat-panel types, with electrodynamic being the most common for automotive use.
Full-range speakers, or coaxial speakers, have their low-frequency and high-frequency units designed on the same axis. The outer part handles low frequencies, while the inner part handles high frequencies, but the sound emission point is at the same physical location. This design eliminates sound drift caused by the different frequency ranges of the high and low units. However, since both highs and lows are emitted from a single point, the tonal distortion is relatively high.
Component speakers are divided into 2-way and 3-way systems. A 2-way system consists of a tweeter and a woofer, while a 3-way system adds a mid-range unit. Because each unit is responsible for a different frequency band, the effective frequency range is broadened, thus solving the problem of tonal distortion. However, in daily life, the sounds we hear are basically emitted from a single point. Since each unit in a component speaker emits different frequencies and is installed at different physical locations, sound drift occurs. In addition, although the high and low-frequency units handle different frequencies, there is inevitably a crossover point. Emitting the same frequency from different locations will cause sound wave interference. To solve these difficulties, a crossover is needed. A crossover, as the name implies, separates different frequencies and sends them to different speaker units. Of course, its function is not just this; it also needs to make appropriate adjustments according to the speaker's characteristics to reduce distortion and interference.
Rated Impedance: The impedance value measured at the input terminal of a speaker at a specific operating frequency. It is an important parameter for matching the speaker with other components in the audio system. If this data does not match the rated impedance of the power amplifier, sound distortion will occur.
Sensitivity (Sound Pressure Level): The sound pressure level measured at an axial distance of 1 meter when a 1 W noise signal is applied to the speaker. It reflects the speaker's ability to produce sound volume. When selecting speakers, try to keep the values of the left and right channels consistent (within ±1 dB), otherwise, there will be an obvious sense of imbalance.
I originally thought that by finding a new car audio dealer every issue, I could get completely new information. However, I didn't expect that among the products recommended by different stores, there were so many similarities. For example, Alpine and Sony for head units, and MB for speakers. The two stores were located at the north and south ends of Beijing respectively, and the identical brands recommended by their managers showed that these brands still hold a certain weight in the market.
