5 Confusing Audio Concepts

- Jan 14, 2020-

Confusion Concept One: Speakers and Audio



Don't underestimate this is a very simple concept. For many little white users, they don't know much about the difference and connection between the two words, and it is easy to confuse the concepts of these two words.




First say audio


It is a complete set of equipment (or a system), and the speaker is an integral part of this set of equipment. It can also be said to be a speaker in the sound. Its role is to turn the electric signal amplified by the amplifier into sound. The signal is transmitted to the human ear;




In addition, the audio also includes external power amplifiers, audio source equipment, decoders, equalizers, microphones, transmission lines, etc. These independent devices are combined to form an audio. What we usually call home theater is a sound system.




2. Let's talk about speakers


Simply put, it is a sound output device, which can also be called a horn (but different from the horn single form); it is composed of a cabinet, a horn single, a crossover and a power supply;




Some speakers have a power amplifier inside, called active speakers; those without a power amplifier are called passive speakers. Basically, active speakers are usually used with PCs at home. Speakers used in home theaters or other audio systems do not have power amplifiers. They need to be connected to external amplifiers.




Section: Audio is a complete system that includes speakers; a speaker is a single sound output device.




Confusion Concept 2: Pre and Post



If there are some enthusiasts who like "burning" equipment around us, you may often see that one or two devices similar to external amplifiers are placed on their desktops; it is likely to be the pre- and post-stages. So what do they do and what is the difference between the two? Let us briefly explain it for everyone.




Front level


The so-called pre-stage refers to a device with effects such as Volume, Bass / Treble, Balance, Tone, and echo. Its function is to process reception. To the audio signal.




However, the output signal of the front stage is very weak. If we directly connect to the speaker, we may only hear a small sound. At this time, we need to send the sound signal to the rear stage for amplification, and then we can hear more loudly. Sounds out.




Post-level


The post stage (also called post stage amplifier) is mainly used to enhance the power of the signal, that is, by increasing the current output in the cabinet, the speaker vibrates and sounds in the magnetic field generated by the current; simply, it transmits the pre stage to Its signal strength increases and then passes to the speaker, and the human ear can hear loud sounds.




The ordinary active speakers on the market integrate the front and rear stages on one circuit board at the same time; the front and rear stages of high-end audio equipment are divided into two devices, and the sound quality performance will naturally be much better.




Section: the front stage is responsible for adjusting the volume and sound effects; the rear stage is responsible for increasing the power of the signal output.




Confusion Concept 2: Operational Amplifiers and Amplifiers



Operational amplifier


The full name of the op amp is called an operational amplifier. Literally, it is used to perform signal operations and amplifications. It can also add or subtract signals. Its operational characteristics were widely used in the computing components of computers in the early days, and then widely used. In various fields.




In the field of multimedia speakers, the op amp chip is mainly responsible for the operational functions of volume, tone and peripheral effect adjustment. For example, the preamp in the audio and the headphone amplifier (amp) will use integrated operational amplifiers.




Different types of op amps have different effects on the sound. For example, when we listen to music, the sounds such as warmth, fullness, dryness, and roundness are obtained through the op amps.




There are many types of op amps on the market. Low-end op amp chips such as JRC4558 are the most commonly used in ordinary power amplifiers and multimedia speakers. Although the sound performance is average, they are low-cost and more suitable for low-end amplifiers and speakers use. In addition, high-end op amps such as NE5532, LM833, and LF353 are mainly used in high-end audio equipment, and the sound will naturally be much better.




2. Amplifier


The amplifier is relatively easy to understand. Its full name is a power amplifier, which is an indispensable device in the speaker / audio system. Its purpose is to amplify the weak electrical signals from the signal source (or the mixer in the professional audio system). After that, a sufficient current is generated to push the speaker for sound reproduction;




Without a power amplifier, the horn itself cannot produce sound. Mainstream high-end power amplifier chips such as TDA7294, LM3886, and LM4766 can make the playback sound extremely affinity (recognized as bile amplifier by audiophiles);




Built-in mute standby, short-circuit current and over-temperature protection make its performance more complete. Can be used in household HiFi audio, active speakers, LCD TVs and other fields.




Section: The op amp is responsible for adjusting the volume and tone, and the power amplifier is negatively amplifying power.




Confusion concept four: digital audio and analog audio



Digital audio


Digital audio is literally understood as the technology of recording, storing, editing, compressing and playing sound through digital means. It is a new sound processing method formed with the development of digital signal processing technology and multimedia technology, and is widely used in post-production and recording of music.




Digital audio itself is a type of data. It converts audio files into digital signals and saves them. The human ear cannot hear them; therefore, it must convert these digital signals to analog signals through a digital-to-analog converter (DAC), and then pass We can only hear the sound through the horn. The advantage of digital audio is that it is easy to store, edit, and produce. What we usually call Dolby sound is digital audio.




2. Analog audio


Analog audio, also known as analog signal, refers to the use of electrical signals to simulate the change in the physical quantity of sound; sound is a signal that continuously changes in time and amplitude, so the analog electrical signal also changes continuously in time and amplitude, so it is called Analog audio signal. However, this signal has many disadvantages in processing, such as poor anti-interference ability, easy to be affected by mechanical vibration, analog circuit distortion, long-distance transmission is greatly affected by the environment, etc .;




Although it is a signal that can be directly heard by the human ear, the real effect is often difficult to hear. Therefore, to hear wonderful music, an analog signal needs to be converted into a digital signal by a device called an analog to digital converter (ADC), also called sampling. After editing and producing, you can get wonderful music.




Section: Digital audio is also called digital signal, which can be edited and produced, but cannot be directly heard by human ears; analog audio is also called analog signal, which can be directly heard by human ears.




Confusion concept five: analytical power and image power



Analytical power


Although the description of sound quality is a very abstract and subjective matter, it is relatively easy to understand the analytical power of sound. We can use the image resolution to understand what is the resolution.




We know that the higher the resolution, the more meticulous the performance of the image, and the better the description of the details. Also for sound, speakers with excellent resolving power can express a lot of sound details. For example, when enjoying a violin song, we can "smell" the smell of rosin, because we can hear a lot of overtones; or listening to drum sounds At that time, we seemed to "see" the drum skin vibrating up and down. The description of these images can be understood as the analytical power of sound.




The higher the resolution, the clearer the picture. The same is true for the sound quality (the clearer you hear)




2. Image power


The image is relatively abstract. It is an experience of space and positioning.




The image-forming power is a more abstract concept, and it is not as analytic as the image, but we still have to explain it to everyone. The sound from a good speaker will make us feel solid and clear.




For example, if we put a set of 5.1 speakers around the room, and then people listen in the center, at this time we will feel that the position of the vocals, instruments, and drums is very obvious, and it is very three-dimensional. This is the end of the sound. Like ability.




Although the sound is ethereal, you can feel that it is an entity that really exists somewhere. Of course, in addition to the quality of the speaker itself, a good sound source is also crucial.