Definition and Functions of an Amplifier
If you are planning to expand your home entertainment system, one of the first purchases you’ll likely make is an A/V Receiver. It is a must-have piece of equipment for many families and one that can improve the overall sound quality. In addition to a quality receiver, is also a good idea to invest in a quality amplifier to get the full effect.
An amplifier is an electronic device that increases the strength of the signal to make sound waves louder. This is often the first step in providing your speakers with better sound quality.
Contrary to what you might think, the amplifier is not always a necessary component for enjoying some great music, watching movies, and playing video games. These functions of the amplifier are realized through the receiver. The receiver acts as the command center, enhancing sound and image quality. It’s the receiver that determines what functions will be available to consumers.
The receiver is also responsible for creating the channels and sources. It’s how you configure the channels that will determine what will be heard. For example, if you set your receiver to LINE, it will only output sounds from your speakers. If you’d rather have your computer connected, you’ll need to change the source to HDMI.
The amplifier is responsible for driving the speakers. Its job is to amplify the signal, usually a low voltage signal, according to the volume level you have set.
Types of Amplifiers
An amplifier or amp is used to make the sound from an audio source louder.
Amplifiers can be either guitar amps, home stereo amps, or other types of amps designed for other uses.
The different types of speakers have different ways of amplifying the sound. Dynamo speakers use sound cones, while magnetic speakers use magnetic fields.
Amplification makes the sound louder but does not even out the sound of a distorted audio source, such as when the sound of a guitar is not amplified enough.
For cars, there is an amplifier to boost the sound. The louder the music is, the harder the rear speakers vibrate. A rear speaker amplifier would make the rear speakers work harder.
The rear speakers are often not charged with enough power. When the bass is present, the amplifier serves to make the rear speakers move more smoothly.
The amplifier in a home stereo system is used to increase the sound, which might not be loud enough.
Based on Circuit Configuration and Method of Operation: Class A, B, AB, and C.
An amplifier's design and operating configuration determine its performance based on the method in which amplification is accomplished. Class A, B, AB, and C are a few of the fundamental configurations used in most amplifiers. Each configuration results in unique sound properties, based on the operating voltage, frequency, transistors, and other factors.
Class A is a method of operation with no bias applied to the base of the transistor. A small amount of the input signal is amplified and fed back into the input. Class B amplifiers also incorporate feedback on the basses. However, bias is applied to force the transistor to operate with the correct class for the proper apex of the input waveform. Class AB amps combine Class B characteristics with Class A characteristics. Class C it's not used in audio amplifiers because of the vast amount of distortion.
The circuit design and method of operation are the primary factors for determining the sonic characteristics of an amplifier. Secondary factors, such as circuit topology, circuit layout, power supply, added components, and material quality will contribute to the sonic quality.
How Does an Amplifier Work?
Let’s create a hypothetical scenario here. Let’s assume that you’re listening to an MP3 file. An MP3 file has been compressed using a form of encryption. In addition, it is being played over a mobile phone speaker, which is one of the least expensive types of speakers.
Now, let’s say that you buy a nice pair of headphones. Headphones are capable of transmitting a higher quality of signal than a mobile phone speaker. Don’t get me wrong here, your headphones are still going to sound worse (not as good) as a high-quality stereo setup.
To make our scenario more interesting, let’s say that you enjoyed your experience with the better quality signal so much that you decided to purchase a quality stereo speaker system. The point of this thought experiment is to point out that although you moved away from the lower quality, less expensive signal, your sound quality didn’t improve all of a sudden. Instead, you continued to experience a better signal quality (albeit not at a higher level). The reason for this is simple.
When you plug in your earphones or connect your speaker system to your speakers, no sound will emanate from them until you turn the amp on.
An amplifier takes the tiny electrical signal produced by a speaker and increases its strength to make it so strong that it can create a sound loud enough for you to hear through your earphones.
But at the same time, the amplifier also distorts that electrical signal, causing the sound you hear to be altered. And as you might know, sometimes distortion leads to noise.
However, if you are listening to your music through earphones as most people do now, an amplifier generally doesn’t add noise. In this case, the amplifier is only acting as an intermediary between your music player and your earphones, and, at this stage, there is no need for the amplifier to distort the signal. This is why that you can use your amplifier to listen to your music at a lower volume and still enjoy your music.
Speakers are slightly different because they have a built-in amplifier. So once the signal reaches your speakers, no other distorting amplifier is needed, and this is why amplifier noise occurs with speakers.
Putting aside the fact that an amplifier makes a weaker signal stronger, an amplifier does not 100% guarantee a good sound. Higher quality amps will result in a clearer sound, whereas cheaper amps will distort the sound.
Factors That Affect Sound Quality
For an amp to improve the sound quality and improve the abilities of the speaker, there are a few factors that need to be considered. Whether the amplifier is worth buying depends almost entirely on the type of speaker used. Taking into consideration what the amp is capable of doing for the speaker is also very important.
Below are some of the most important factors to consider.
The first is power. The word power means different things to different people. In this context, it simply refers to the ability of a speaker to create sound.
The higher the wattage, the better. So if you want to enjoy enhanced sound quality via a speaker that requires more power, investing in an amplifier is a good idea. Just keep in mind that all speakers require different power. Some require high-pitched power, and some require low-pitched power.
A second factor is bass response. Some speakers may not provide a good bass response. In this case, an amplifier will help the speaker improve its bass response.
A third factor is wire gauge. The wire is used to transfer the electrical signal to your speaker. The thicker the wire gauge, the higher the quality sound the speaker can produce. So instead of investing in an amplifier that can improve sound quality in general, you may want to look for one that can improve the durability of your speaker and enhance its overall performance.
If you want to improve the sound quality of your car speakers, the amplifier isn’t the solution. Of course, if you’re listening to your stock speaker system, an amplifier could make the sound crisper and clearer, and perhaps louder. But if you’re already happy with the sound quality of your speaker system, adding an amplifier won’t help or improve sound quality.
To boost the quality of the sound you’re listening to, your best option is upgrading the speaker system by purchasing better quality speakers or components (i.e. amplifier/speakers combination). Also, because many speakers use matching crossovers, buying better quality components that use the same brand crossovers will ensure top-notch sound.
The speakers and the audio source itself have a much bigger impact on sound quality than the amplifier does. An amplifier can increase the maximum volume of your sound device and can boost the audio signal to make it louder.
But sound quality depends on how the audio signal is first being generated. This includes the quality of the components used to manufacture the amplifier. A cheap amplifier can actually worsen the sound quality.
The main reason why you would want to purchase a separate amplifier is to improve the volume of an audio source. Whether that helps or not depends on the quality of the speakers you are using.
So, if you’re looking to improve the sound quality, then the first change you should make is in the speakers rather than the amplifier.
Tips to Get Better Sound From Your Audio System
There’s no doubt that a quality AV receiver can take your sound to a whole new level. However, the real debate lies in whether or not you should opt for an amplifier to get better sound from your speakers.
There is some truth that an additional amplifier can improve the sound quality of your speakers. However, it depends on your situation and needs. If you’re looking to upgrade the sound quality in your room, then you can’t go wrong by investing in high-quality speakers and an AV receiver. This would be sufficient to pump up the volume, response, and dynamic range of your music.
If you’re simply looking to increase the volume levels without losing out on sound quality, then it’s not worth the fuss. An AV receiver provides more than enough power to drive all the speakers in your home theater. Adding another amplifier is not going to give you that much of a benefit.
Check Your Gear
Your amplifier is responsible for transforming the electricity of the power source into the current that your speakers need to vibrate and emit sound waves into the air. If your amplifier isn’t working properly, you won’t hear any sound from your speakers.
In other words, if your amplifier cables are in good condition and your speakers are functioning and causing sound waves in the air, you can guarantee that the amplifier not doing its job correctly is likely the cause of your speaker issues.
In many cases, bad amplifiers are just out of power or are not wired correctly. However, in other situations, the amplifier might just be worn out and need to be replaced. Here are a few signs that your amplifier is giving up on you.
Poor Quality Sound
If your sound is no longer as crisp and clear as it used to be, you might need to replace the amp. When the amp is weak or damaged, it cannot drive your speakers to a sufficient level. This leads to issues with sound distortion.
If you play the same track on repeat and start noticing that the pitch sounds different and that the music was out of tune, the problem might be your amp.
Some amps only have one cable, so just make sure that the amp is properly wired.
Work on Your Room Acoustics
I get this question a lot. Many people believe that you need an amplifier to achieve excellent sound quality in your home theater. Here’s the truth: most of the time an amplifier alone will not improve the audio quality of your home theater. An amplifier is a simple electronic device that increases the amplitude of a signal. In terms of home theater systems, it’s important to understand that amplifiers will not make your movies, concert DVDs, or video games sound any better without fitting well into the bigger picture.
If you notice a lot of distortion and buzzing coming from your speakers, it’s generally not caused by a lack of audio power. Instead, it’s likely the result of poor room acoustics. Poor acoustics can impede your ability to hear everything clearly.
To fix this problem, you need to zoom out and examine the room and its contents. Are there holes in your walls or objects in the room that are diffusing audio waves? Is your ceiling conducive to quality acoustics?
Position Your Speakers Correctly
Speakers are the most important component of any speaker system. The quality of the sound produced by a speaker is also greatly dependent on where it is placed in a room. Depending on the size of the room, speakers are positioned in different locations for optimal sound, but if you're designing your own sound system, you'll want to consider speaker placement right from the beginning.
The optimal placement for the right speaker is above the listener's right shoulder. If you only have one speaker, try to position it midway between the listener's ears (this is usually about four feet behind and above your head). If you add a second speaker, position the left speaker to the left of the listener, again between 4 and 6 feet away and on the same line as the right speaker.
The further apart the two speakers are, the greater the frequency difference will be and this can lead to phase problems, particularly at higher frequencies. You may need to move the speakers back if the bass is too "boomy." Moving the speakers closer to the wall behind them will decrease the bass response.
The most natural sound is achieved when your speakers are equidistant from the listening position. This may mean that the speakers are closer to you than is ideal as far as the acoustics of the room are concerned, but if they are not equidistant, you will get a less than natural sound.
Adjust the Sound Settings on Your Receiver/Amplifier
Before you splurge on an amplifier and new speakers, make sure the sound from your home entertainment system is just as loud as you want. You might have to adjust your receiver to control the level of sound coming out of your speakers. Sometimes all you need to do is turn up the current volume setting. Most receivers have an input setting that allows you to control the volume for each input device you connect to it (cable/sat box, DVD, etc.). This is the first step in solving a weak sound issue, before rushing off to buy new speakers and an amplifier.
You can also better control the volume of your speakers by using volume level (or gain) knobs on your home speakers. You can adjust them from the back of the speaker or, in the case of floor-standing speakers, on the speaker grills.
Or you can add a subwoofer to your existing home speakers and make your system sound significantly better, but it will be much more expensive than purchasing a new amplifier.
In an ideal world, our systems would be able to pump out everything that a program has to offer. Unfortunately, in our imperfect world, there are limitations and imperfections from one part to the next. That’s why some amplifiers are classified more as ‘power amplifiers’ rather than ‘high fidelity'. Think of it like a person in the crowd yelling to his friend across the stadium. A person needs a loud yell to communicate over the distance, so the person would be very loud in your ear, but his voice would be muffled. That kind of system will need a power amplifier. Maybe even a few more.
So overall, a really good amplifier just improves every part of your system. It creates a more realistic sound stage with higher fidelity. It takes care of the ‘weakest links’ in your setup, letting you get closer to your true power and fidelity. The more powerful the amplifier, the easier that process becomes.