Knowledge of speaker products based on popular science

                               Knowledge of speaker products based on popular science

Distinguish according to the nature of the speaker

Active speaker is also called "active speaker". It usually refers to speakers with power amplifiers, such as multimedia computer speakers, active subwoofer speakers, and some new home theater active speakers. Since the active speaker has a built-in power amplifier circuit, the user does not have to consider the problem of matching with the amplifier, and it is also convenient to be directly driven by a lower-level audio signal.

Passive speaker: (Passive Speaker) is also known as "passive speaker". Passive speakers are ordinary speakers that we usually use without power amplifier circuits inside. Although passive speakers do not have amplifiers, they often have crossover networks and impedance compensation circuits.

The basic composition of the speaker

Housing material

The box is made of baffles.

The vibration caused by internal standing waves, the energy of these waves can be transmitted to the cabinet; the vibration of the speaker itself is transmitted to the cabinet. Some problems caused by the process, such as the installation of the speaker is not firm enough, etc., will cause the box to vibrate. Box vibration creates new sound waves that degrade the sound quality.

Cabinet decoration process

The acoustic structure of the speaker

When the speaker diaphragm is working, it will simultaneously drive the air in front and behind the diaphragm to form two sets of sound waves, but the phase difference of these two sets of sound waves is 180 degrees, that is to say, the peaks and valleys of these two sets of sound waves are opposite and will cancel each other out, causing the sound pressure to drop ;In order for the sound to be effective, the speakers need to be used with boards, these boards are called baffles. Different combinations of these baffles form different boxes, which cooperate with the speakers to form different structures. These structures are called acoustic structures and determine some basic characteristics of the speakers.

The most common structural methods are: inverted type and closed type

Classification of speakers

The loudspeaker is an important part of the speaker, it is the sound-generating component, and it is the soul of the speaker. There are many kinds of loudspeakers, and there are many classification methods, including radiation method, composition, energy conversion method, diaphragm form, frequency, use and other classification methods.

Diaphragm Manufacturing Materials

Silk film is the collective name of silk film and silk film, because the two have a high similarity, so they are often collectively called silk film.

Silk membrane speakers have a relatively soft and durable acoustic sense of hearing, and their transient and dynamic performance can be recognized by most people. Therefore, most tweeters use silk membranes. Compared with other materials, they have a wider range of applications much.

Metal diaphragms are mainly divided into three types, aluminum alloy, titanium alloy and beryllium alloy. The most common is aluminum alloy diaphragm, followed by titanium alloy, and beryllium alloy is extremely rare because of its rarity and toxicity.

The metal tweeter has higher frequency response characteristics, rich high-frequency details and excellent transients. However, the metal tweeter is prone to glitches and hearing fatigue.

Plastic diaphragm has high plasticity, easy processing, low cost, but poor rigidity. If you want to obtain better rigidity, you need to increase the thickness of the diaphragm. It is not an ideal treble diaphragm material, but due to the cost advantage , There are a lot of use in low-end speakers.

Paper-based diaphragm, the paper cone is the most common type of diaphragm for woofers, and its material is paper. This material has moderate strength and damping, has a good natural sense of hearing, and the sound is infectious. Its consistency is not good, far inferior to plastic and metal diaphragms. It is also easily disturbed by the environment, and its water absorption is too high. In wet weather, it will absorb moisture, which will increase its own weight and reduce its stiffness, which will affect the acoustic performance. Therefore, the paper cone is often coated to improve its shortcomings.

Woven diaphragm, glass fiber can also be processed into a diaphragm through weaving, commonly known as bulletproof cloth basin. The advantage of this material is good rigidity, resistance to deformation, and good transient and dynamic performance of sound. But easy to appear blunt.

Divider

If the speaker uses both tweeters and woofers, then the frequency divider is essential and very important. But for full-range loudspeaker-based cabinets, it's not necessary.

The treble and woofer will attenuate at both ends, and the upper limit attenuation point of the bass frequency response may overlap or interlace with the lower limit attenuation point of the treble, resulting in a large overlap of frequency segments, which cannot be combined into a flat frequency response curve. At this time, other components must be used to help the speakers complete the combination to achieve better results. The name of this component is the frequency divider.

The function of the frequency divider: "cut" out a frequency band that is most suitable for the corresponding speaker and distribute it to the speaker, so as to realize the collaborative work and optimal combination of multiple speakers.

The common ones are power frequency divider and electronic frequency divider; the latest technology is now: pure digital frequency divider

In the signal flow, it is located after the power amplifier, so it is called a power divider. It mainly uses inductors and capacitors, so it is also called an inductance-capacitance frequency divider. Both the inductance and the capacitance have a filtering effect, and realize low-pass and high-pass respectively, and realize the ultimate goal of frequency division.