Op amps are tiny amplifier circuits built into miniature chips used for all sorts of audio functions. Ground loop noise is a common and very frustrating car audio installation problem. This appears as a high-pitched and annoying whine you can hear from your speakers.
A filter design called a differential amplifier circuit is used on the front end input side to effectively block and cancel out this noise before it can get into the musical signal pathways. Electronic crossovers offer a way to control the frequency range sent to car speakers. For example, when driving subwoofers, a low pass filter blocks everything except bass to give a great bass sound.
Likewise, you can prevent bass from distorting smaller speakers such as tweeters or door speakers by using the high pass crossover. When used correctly crossovers allow you to get more volume, protect your speakers, and provide better sound clarity. Electronic crossovers in amps perform the same function as passive speaker crossovers but without bulky components like inductors and capacitors they require.
As the name implies, amplifiers boost an input signal from a stereo. The amplifier gain adjustment provides a way to control the output level based on the input signal level. The gain level affects the headroom which is the amount of amplification still available before the limit is reached. All types from car to home stereos and even home DJ equipment often include a gain adjustement. Simplified illustration of the amplification stages and output that most car amps use.
Beefy output transistors capable of handling large amounts of current are connected to the switching power supply and drive the speaker. Power amplifiers as seen in the image above have main sections dedicated to modify or manipulate audio signals as well as for delivering more current and voltage. The first sections contain small components like miniature transistors that divide the audio signal into two halves.
The input signal is magnified to an identical but much larger waveform connect to the speaker outputs. The class listed by a car audio amplifier manufacturer is the type of technology used for the audio signal and to deliver power.
This is wasted purely as heat! By contrast, a class D amp uses pulse width modulation PWM technology that switches power components on only a portion of the time. These are converted back to smooth audio signal waves before being delivered to speakers. This is easy to understand. Similarly, we do not want a loudspeaker to demand too much power from a power amplifier.
As discussed in the previous section, this is a bit trickier to understand and is why some amps are not suitable for low-impedance drivers. This is actually arguable worse than the reverse scenario. Large speakers require large signals and are capable of producing large amounts of Back EMF that could potentially damage the amplifier. On top of that, trying to drive a large speaker with a low-power signal will not sound as clear as a well-amplified signal.
Turning the amplifier up may lead to clipping, which sounds awful and runs the risk of damaging the amplifier and perhaps even the loudspeaker. Speaker sensitivity is the capability of the speaker to convert electric power from an amplifier into sound. It is a measurement that refers to how loud a speaker will be at a given input signal level. That is the sound pressure level in decibels that the speaker will output, measured at a distance of 1 meter from the speaker when 1 watt of power is dissipated across the speaker.
This is important because sound pressure level naturally drops by 6 dB for every doubling of distance. Therefore, referencing the sensitivity ratings, we have:. Next, we must understand that there will be an increase of 3 dB in SPL for every doubling in power. So, then, we have the following values at a distance of 1 meter:. So for our calculated listening position, we must find a speaker capable of outputting the necessary SPL and able to handle the amount of power required to produce that SPL.
Then we must find an amplifier capable of supplying that much power to the loudspeaker while also being compatible in terms of impedance bridging. The following picture should illustrate the above points by showing speakers A and B with various amplifier output power and listening distances:.
Prolonged exposure to high sound pressure levels can cause hearing damage. Are bigger speakers better? Bigger speakers, generally speaking, can move more air, thereby producing higher sound pressure levels and more bass frequencies.
That is, by no means, to say that bigger speakers have higher fidelity or perform better than their smaller counterparts. There are plenty of other factors to consider. Are amplifiers with higher wattage louder?
When turned up and matched with a capable loudspeaker, this may translate to more loudness. Choosing the right PA speakers for your applications and budget can be a challenging task. Check it out for help in determining your next PA speaker purchase. With so many loudspeakers on the market, purchasing the best speaker s for your applications can be rather daunting. Check it out for help in determining your next speaker acquisition. Choosing the best power amplifier for your car, home sound system, or pro audio application can be a complicated assignment.
Check it out for help choosing the best power amp for your applications. He's an audio engineer by trade and works on contract in his home country of Canada. When not blogging on MNM, he's likely hiking outdoors and blogging at Hikers' Movement hikersmovement. Check out his Pond5 and AudioJungle accounts. Thanks for letting us know! Email Address Sign up There was an error. Please try again. You're in! Thanks for signing up. There was an error. Tell us why!
More from Lifewire. Woofers, Tweeters, and Crossovers: Understanding Loudspeakers. Home Theater Receiver Connections Explained.
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To do this, you need to boost the audio signal so it has a larger current while preserving the same pattern of charge fluctuation. This is the job of the amplifier. It simply produces a more powerful version of the audio signal. In this article, we'll see what amplifiers do and how they do it. Amplifiers can be very complex devices, with hundreds of tiny pieces, but you can get a clear picture of how an amplifier works by examining the most basic components.
In this next section, we'll look at the basic elements of amplifiers. In the last section, we saw that an amplifier's job is to take a weak audio signal and boost it to generate a signal that is powerful enough to drive a speaker. This is an accurate description when you consider the amplifier as a whole, but the process inside the amplifier is a little more complex.
In actuality, the amplifier generates a completely new output signal based on the input signal. You can understand these signals as two separate circuits. The output circuit is generated by the amplifier's power supply , which draws energy from a battery or power outlet. If the amplifier is powered by household alternating current , where the flow of charge changes directions, the power supply will convert it into direct current , where the charge always flows in the same direction.
The power supply also smoothes out the current to generate an absolutely even, uninterrupted signal. The output circuit's load the work it does is moving the speaker cone. The input circuit is the electrical audio signal recorded on tape or running in from a microphone. Its load is modifying the output circuit.
It applies a varying resistance to the output circuit to re-create the voltage fluctuations of the original audio signal. In most amplifiers, this load is too much work for the original audio signal. For this reason, the signal is first boosted by a pre-amplifier , which sends a stronger output signal to the power amplifier. The pre-amplifier works the same basic way as the amplifier: The input circuit applies varying resistance to an output circuit generated by the power supply.
Some amplifier systems use several pre-amplifiers to gradually build up to a high-voltage output signal. So how does the amplifier do this? If you look inside an amplifier for an answer, you'll only find a complex mass of wires and circuitry components.
The amplifier needs this elaborate setup to make sure each part of the audio signal is represented correctly and accurately. Hi-fidelity output requires very precise control.
All of the pieces in an amplifier are important, but you certainly don't need to examine each one to understand how an amplifier works.
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