How much do you know about active speakers ?

                                        How much do you know about active speakers?

1. The price is relatively easy to accept

The casing of an independent external power amplifier should have sufficient mechanical strength and good shielding performance. The cost of some well-made casings often reaches 15-20% of the total cost. The power amplifier of the active speaker is set inside the speaker, and there is one less case than the power amplifier, so the cost can be greatly reduced. In terms of power amplifier circuit, the external power amplifier generally adopts discrete components, the sound quality is better but the cost is higher, and the installation and debugging are complicated, and the production is difficult. Active speakers generally use power integrated circuits, which are low in price, simple in design, generally do not need to be debugged, and have complete protection functions and are easy to mass produce. This keeps the cost of powered speakers down even further. In terms of wire, the price of excellent audio wire is quite expensive. Active speakers only need one speaker cable, while ordinary speakers need at least one pair, which reduces the cost of active speakers a lot.

2. Simple connection and convenient use

The active speaker greatly simplifies the link of the audio system, so the connection is simple. Only a walkman and a pair of active speakers are needed to form the simplest audio system, and there are only two connections.

3. Save the trouble of matching

The matching of audio equipment is very important, especially the matching of power amplifiers and speakers. There are many manufacturers of audio equipment with different styles. If they are properly matched, the styles of each equipment can complement each other and produce a satisfactory sound. If it is not matched properly, it is not harsh but soft as mud. It is very difficult for ordinary consumers to be familiar with the characteristics of equipment from many manufacturers. The power amplifier and the speaker of the active speaker are produced by the same manufacturer, sometimes even designed by the same person. The problem of matching can be solved before leaving the factory, which saves the user trouble.

★The composition of active speakers

The composition of active speakers can be divided into active and passive parts. The active part is mainly composed of power amplifier components and power transformers. The power amplifier component is used to amplify the music signal and realize various control functions, while the power transformer provides power for the power amplifier component. The passive part mainly includes speakers, frequency dividers and speaker cabinets.

The loudspeaker is the final sounding device of the entire audio system. At present, most active speakers use a dynamic design, which has a simple structure, low cost and good performance, but it is difficult to meet the different requirements of the treble and bass for the speaker, so it must be Using two types of units for treble and bass respectively, it not only provides good sound quality, but also ensures the integrity of the frequency band. The playback frequency of the woofer is generally between 20 and 6000Hz, and most of the calibers are between 3 and 8 inches. The tweeter is generally small in size, the playback frequency is 1500-25000 Hz, and the diameter of the diaphragm is between 12-25 mm.

The function of the frequency divider is to distribute the signal to the tweeter and woofer respectively according to the frequency, and a high-level designer can also use the frequency divider to adjust the timbre of the sound. Another function of the frequency divider is to prevent high-power low-frequency signals from damaging the tweeter. Generally, low-end active speakers only use the simplest single-capacitor frequency divider, which is low in cost but poor in effect, while high-quality speakers are equipped with a real frequency divider composed of multiple components that has been carefully designed and adjusted.

The function of the cabinet is mainly to prevent the phenomenon of "acoustic short circuit". The phenomenon of "acoustic short circuit" refers to the cancellation of the sound waves emitted by the front and back of the speaker due to the similar phase, mainly in the low frequency band. If the speaker is not installed on the speaker, there will be no bass. The function of the box is to isolate the sound waves on both sides of the speaker to avoid the phenomenon of "acoustic short circuit".

The combination of loudspeaker, frequency divider and cabinet is the top priority of active speakers and the decisive factor for the sound quality of active speakers. For multimedia active speakers, this combination determines more than 70% of the sound quality of speakers.

How to classify and select speakers

A speaker is a device that restores an electrical signal to a sound signal, and the authenticity of the restoration will be an important criterion for evaluating the performance of the speaker.

The speaker system of the active speaker* (that is, the power amplifier). The power amplifier and speaker sound system are integrated, which can be directly matched with general audio sources (such as Walkman, CD player, DVD player, VCR, etc.) to form a complete audio combination. With active speakers, there is absolutely no need to purchase additional power amplifiers, and you no longer have to worry about choosing a reasonable power amplifier and speakers. It is easy to operate and has a high cost performance.

According to different sounding principles and internal structures, speakers can be divided into several types such as inverted type, closed type, flat type, horn type, and labyrinth type, among which the most important are closed type and inverted type. The closed type is equipped with a speaker on a closed box, and the efficiency is relatively low; while the inverted type is equipped with a circular phase-inverted hole on the front or rear panel. It works according to the principle of the Helmholtz resonator, and has the advantages of high sensitivity, high withstand power and wide dynamic range. Because the sound waves on the back of the speaker are emitted from the inverter hole, its efficiency is also higher than that of the airtight box. Moreover, if the same speaker is installed in a suitable phase-inverted box, the low-frequency sound pressure obtained by installing it in a closed box with the same volume will be 3dB higher, which is also beneficial to the performance of the low-frequency part, which is why the phase-inverted type is widely popular the main reason.

In terms of structure, speakers can be divided into bookshelf type and floor type. The former is small in size, clear in layers, and accurate in positioning, but the power is limited, and the extension and volume of the low frequency band are insufficient. Audiences and multimedia enthusiasts; the latter is larger in size, higher in power, has a strong sense of volume and flexibility in low frequencies, and is good at expressing torrential momentum and powerful shock.

For lovers of different music, this is also an important content that should be understood before purchasing. Since ordinary families rarely have the conditions to place large floor-standing boxes, compact desktop bookshelf speakers should be the first choice for multimedia active speakers. In general: as long as the design of the power amplifier module is reasonable, the larger the cabinet, the larger the speaker, and the more pleasant the sound.