At present, the car audio market has a wide range of products, including mainframes, power amplifiers, speakers, processors, audio and video equipment. For the host only, there are CD host, VCD host, DVD host, and host with MP3 function. There are many famous brands all over the world, and the product types are hundreds of millions. However, the basic matching of a set of sounds is skillful. All kinds of equipment need to be carefully selected to get the best results.
So, is the power amplifier and speaker in the car audio any match?
Only the power amplifier and the speaker can achieve impedance matching, power matching, and working frequency matching to ensure the safe operation of the equipment and fully exploit the maximum potential.
What is impedance matching?
Aside from the boring theoretical knowledge, the simple explanation is that the power amplifier can withstand a range of impedance speakers. Only if the speaker impedance connected to the amplifier is within this range, the power amplifier can work safely and provide the best power output! Different types of power amplifiers can withstand different impedances. For example, the rated impedance of the Alpine MRV series amplifier is 4 ohms (4 ohms per channel), and the rated impedance of the MRD series amplifier is 2 ohms.
What is the power match?
When we perform power matching, we must first figure out two indicators of the usual nominal power: maximum power and continuous output power (RMS).
There are many brands of power amplifiers and speakers that are accustomed to the advantages and disadvantages of the maximum power evaluation equipment. In fact, this is a very unscientific method of judging. The maximum power is nominally the power value at which the device does not experience physical or electrical damage for a very short period of time (usually only a few milliseconds) without regard to distortion.
Continuous output power (RMS) is the power that can continue to operate stably without distortion. Only this value can truly reflect the working state of the device.
Usually the main factor that many people may cause the speaker coil to burn out is that the power of the power amplifier is larger than that of the speaker. Therefore, when the equipment is matched, the power of the speaker is much larger than that of the power amplifier. This is a very common mistake!
In fact, the continuous output power of the amplifier is less than the continuous output power of the speaker, which is the most likely to cause the destruction of the speaker. Because if the power amplifier's continuous output power is 100W, the speaker's continuous output power is 200W. When the system is connected, once the volume knob is adjusted and the output power is around 100W, the power amplifier is already in full-load operation. The speaker still has a lot of margin. Once the user continues to increase the volume, the output power at this time exceeds the continuous output power value of the power amplifier, that is, the moment when the distortion starts to occur! This type of distortion is known as "clip distortion" and is known as the "speaker killer" in the professional audio industry. This distorted signal, even with low power, produces a DC-like electrical signal that can easily burn the speaker's coil! For a speaker with a continuous output of 200W, a 150W electrical signal with a distortion rate of 50% is more terrible than a 300W signal with no distortion!
Therefore, in the field of professional audio, maintaining the "balance" of the power amplifier is an important factor in the system. It is customary to ensure that the continuous output power of the bass power amplifier is more than twice the continuous output power of the speaker! In car audio, since the power inside the car is extremely limited, the power per 1W is precious, so it is the best choice to ensure that the continuous output power of the power amplifier is slightly larger than the continuous output power of the speaker. Don't let power amplifiers with too low power to drive speakers with high output power. When you have to do this, you should pay attention to controlling the volume to prevent the occurrence of clipping distortion!
Frequency matching
Power amplifiers are usually divided into full-band amplifiers and bass-specific amplifiers. The bass dedicated power amplifier with a signal frequency below 250 Hz can guarantee a distortion of less than 1%. When the frequency exceeds 250 Hz, the distortion suddenly rises and the output power suddenly decreases. So don't try to boost the midrange and tweeter with a bass dedicated amplifier.
Full-band power amplifiers are typically designed with Class AB amplification and have a large power loss. Therefore, filtering out the signals in the low frequency band and only pushing the middle and high frequency speakers will be the best choice for saving power and ensuring sound quality.
As long as you master the above device matching principle, you can basically ensure that the speaker and power amplifier are in a safe state and can restore pure and distortion-free sound.
