With the improvement of living standards, the audio-visual field is becoming more and more popular. More and more people are interested in music. However, when they first enter the field, many fans are often puzzled by some professional terms. How to buy sound products with high cost performance ratio, how to combine and match audio equipment in a standard and reasonable way, and what audio equipment will often encounter Fault These are the problems that every new comer must face, and these knowledge can't be digested and absorbed in a short time only by full of enthusiasm and interest.
1、 Introduction to acoustics from knowledge
Learning has always been the first to start from the theory, understanding audio equipment is no exception, familiar with professional audio knowledge and professional terminology is the first step to play with audio equipment, lay a good foundation, in order to better forward. The colorful and complicated audio terms make many people "head big". Due to the limitation of space, the editor will briefly introduce the commonly used terms, so as to facilitate your quick introduction.
Output power: it indicates the output power of the power amplifier under a certain load. Generally, the output power under 8 ohm load, 4 ohm load or 2 ohm load is indicated in the power amplifier manual. At the same time, the output power of the power amplifier under bridge state, 8 ohm load or 4 ohm load will also be indicated. This output power represents the rated output power of the amplifier, not the maximum or peak output power.
Load impedance: it indicates the load capacity of the power amplifier. The smaller the load impedance, the stronger the current capacity that the power amplifier can pass. Generally speaking, the minimum load impedance of most power amplifiers is 4 ohm, and the minimum load of high-quality power amplifiers is 2 ohm. It can load 4 ohm power amplifier in dual channel, 8 ohm in bridge state, 2 ohm power amplifier in dual channel and 4 ohm in bridge state. The bridge state can only load 8 ohm power amplifier, can not load lower impedance, otherwise the power amplifier will be burned because of excessive current.
Frequency range: it indicates that the power amplifier can amplify the working frequency band, which is generally 20-20000 Hz. Generally, there is a suffix after this data, such as - 1 / + 1dB, which represents the error or floating range of this frequency range. This value is about small, indicating that the frequency response curve in the frequency range is more straight. If the frequency response range of the power amplifier is - 3 dB, the sound from the power amplifier may not be so straight.
Damping factor: This is the ratio of internal resistance and load impedance of power amplifier. Damping coefficient = impedance of speaker × (internal resistance of power amplifier + impedance of speaker line). Power amplifier with high damping coefficient can enhance the control ability of speaker unit, which can make the unit response closer to the requirements of power amplifier output signal. However, too high damping coefficient will lead to poor low frequency ductility and dry sound Hard. Lower damping coefficient can get soft bass, but lower damping coefficient will cause bass to become sluggish and unclean. The common power amplifier damping coefficient is 200-[ email=1000@8 ] 1000@8 [/ email] between ohm. The poor quality of the speaker line and the high line resistance will also affect the damping coefficient of the power amplifier, which will weaken the power amplifier's control over the speaker and disperse the sound.
Input sensitivity: This is a voltage concept, which indicates the signal voltage at the input when the power amplifier reaches full power output. The input sensitivity voltage of general power amplifier is between 0.775v (0dB) and 1.5V (+ 6dB). The higher the sensitivity voltage, the lower the input sensitivity. Some high-quality power amplifiers have low input sensitivity due to the use of deeper negative feedback circuits, so they have lower distortion, wider frequency response and better sound quality.
Signal to noise ratio (s / NORs ror human noise): refers to the ratio of the signal voltage and the background noise voltage of the power amplifier. The higher the value, the lower the noise of the power amplifier. The signal-to-noise ratio (SNR) of general professional products is about 100 decibels. When positive value is used, the higher the better (some power amplifiers are marked with negative value, and the smaller the value, the better). Attenuating the input level gain (turn down the amplifier volume knob) will reduce the signal-to-noise ratio of the power amplifier.