The easiest but most important 10 tips on active speakers

Most of our common speakers are active, but how much can you know about it? Today, the editor found 10 tips that must be remembered in the forum. Let’s share them together.

Magnet size
The magnetic strength of the magnetic steel affects the control force of the diaphragm, and the magnetic strength is related to the size of the magnetic steel and the magnetic density. This is evident in the bass unit in the speaker. In the case of the same magnetic density, the size of the magnetic steel determines the magnetic strength and determines the level of control. The magnetic density is related to the magnetizing time and the magnetizing material. Some rare metal alloys can often provide much greater magnetic strength under the same magnet size. Some people say that the weight of the speaker is too light to not be considered, because the size of the magnetic steel greatly affects the net weight of the speaker. In the case of non-use of special magnetic materials, too small magnetic steel is often the crux of bad bass. The oversized magnet has another drawback, that is, it is easy to break during transportation and deform the frame. Therefore, manufacturers generally rarely use exaggerated magnets.

Woofer caliber and long stroke

The caliber of the woofer often determines the depth and volume of the bass. Why does the caliber feel this? In fact, the size of the low volume feeling is related to the volume of the pushed air. The larger the pushed volume, the stronger the low volume feeling. In the case of the same stroke, the larger area of the diaphragm can push a larger volume of air, which is the relationship between the aperture and the sense of volume. In order to increase the sense of volume within a limited caliber, increasing the stroke of the motion is an effective way. Many speaker manufacturers have also done this. Many speakers have put a "long-stroke woofer" in their publicity in order to reflect their low volume. Typeface. The benefits of long strokes to improve low volume are very obvious, but too long strokes also tend to make the action cycle of a stroke longer. When performing music with too fast rhythm, many woofers cannot completely complete one action. Enter the next stroke, causing the bass to become chaotic. It is often described as "slower bass speed".

Inverted and closed
The acoustic structure of the sound box is mainly divided into inverted type and closed type. In most subwoofers or 2.0 speakers, you will see a hole. Some friends call it a "heat vent" or "air hole". In fact, it is called an inverted hole. And there is often a tube inserted into the inverted hole, and this tube is called an inverted tube. The closed design is completely sealed. When the loudspeaker of the airtight box does the action of pushing the air to the outside, the volume inside the box actually increases. The airtight box causes the air pressure inside the box to be different from that outside the box, and the speaker diaphragm will be quickly pressed back by the outside air pressure, so that the loudspeaker The stroke distance becomes shorter, so the bass diving of the closed box is relatively poor, but its bass performance tends to be cleaner and faster than the inverted type.
The cabinet of the inverted design is connected to the outside atmosphere. When the speaker is in a stroke motion, the difference between the air pressure inside the cabinet and the air pressure outside the cabinet will not be as large as the closed type. This design can often promote a larger air volume. , So the low volume feels better (note: the inverted phase design is by no means as simple as opening a mouth). At present, most multimedia speakers have adopted an inverted design. In the inverter box, according to the position of the inverter hole, it is divided into two types: the front inverter and the rear inverter. The inverter hole on the front panel of the speaker becomes the front inverter, and vice versa. Under normal circumstances, the front phase inverted structure can promote a better low volume feel, but it also brings some other problems.

Box volume
The volume of the cabinet also determines the size of the low volume. The most direct benefit is that the large cabinet can be installed with large-diameter speakers, and the large-diameter speakers can directly improve the low-volume perception. The increase in the volume of the cabinet will also change the change in the pressure difference between the inside and outside of the cabinet caused by the stroke movement of the speaker. The large cabinet volume can make the bass become more flexible and have a sense of volume. When we evaluated an X.1 speaker, visually inspecting the size of its satellite box is a necessary inspection item. A satellite box that is too small cannot achieve a sufficient low-frequency limit, so there is a fault in the low-frequency connection with the subwoofer. A period of frequency depression leads to poor hearing.

Low-frequency sense of direction
Generally, speakers will give a frequency response range parameter, such as 20-20kHz, this 20Hz is the lower limit of its low frequency. X.1's low-frequency lower limit generally reaches lower frequencies, so what about their satellite boxes. Taking into account the actual situation of user desktop tension, most of the X.1 satellite boxes are as small as possible, but due to the limitation of the speaker diameter and the volume of the box, the low frequency of the satellite box cannot reach an ideal value. In many articles, there is a saying that it is difficult to hear the direction of the sound source at low frequencies. In fact, this statement is not correct. In fact, it is difficult to hear the direction at low frequencies less than 150Hz. A perfect design requires the low frequency of the satellite box. The lower limit reaches 150Hz or even lower, and it is difficult to achieve a miniaturized satellite box.
Speaker designers can only compromise the status quo, or let this fault exist, for example, the satellite box dives to 250Hz, and the upper limit of the subwoofer is set to 150Hz, so that the subwoofer can be placed more randomly, but there is a 151 -249Hz depression, listening to some concerts seems tasteless, another way is to increase the upper limit frequency of the subwoofer to the lower limit frequency of the satellite box, let the subwoofer emit a frequency greater than 150Hz, so that the connection is solved, but Positioning becomes a hassle, because the bass is easy to be heard, and it is not like "the subwoofer can be placed at will" as some articles say. Under normal circumstances, only a 4-inch caliber satellite box can reach the ideal low frequency lower limit, but such a satellite box is too large and uncommon.

Placement of the subwoofer
Since some subwoofers are forced to raise the upper limit in order to compromise the lower limit of the low frequency of the satellite box, so that the subwoofer can hear the direction, then is there any way to alleviate this situation as much as possible? The answer is positioning. In the X.1 system tested before, we can even mention the human voice in some subwoofers, which needs to be solved by positioning. The correct placement method is that the subwoofer should be placed in the middle of the satellite box as much as possible.
The subwoofer is generally an inverter box, we can see an inverted hole, when the bass is surging, this inverted hole can push out a strong airflow. If the inverting hole is designed on the rear panel of the subwoofer, the rear panel of the subwoofer should not be close to the wall, but a certain distance should be kept. The subwoofer should not be close to other objects, the bass will become muddy after reflection. It is more reasonable for the subwoofer to be placed in a relatively empty and stable place. Many subwoofers pursue the so-called super bass effect too much, causing the bass to become very muddy. You might as well find a piece of cotton cloth that is tightly rolled, and then plug the inverted hole on the subwoofer. The bass will be much cleaner immediately.

Placement of satellite box or 2.0 speakers
2.0 speakers are basically prepared for listening to music, so there should be more requirements for placement. Most of the 2.0 speakers are equipped with 4 small rubber pads, in order to make the bottom of the speaker less contact with the desktop, and these rubber dots often do not achieve a good effect, it is recommended to use Go pieces, 3 Go pieces Set up a speaker, the surface of the Go piece is in contact with the desktop, and coins are also used. The speaker may vibrate when playing some bursting songs. It is recommended to put some heavy objects on top of the speaker, which can significantly improve the sound quality. Like the subwoofer, if you feel that the bass of the speaker is muddy, you can also try to plug the inverted hole if some improvement measures are not very effective.
The front and rear satellite boxes of X.1 should be placed on the same level as possible, which is conducive to sound positioning. When placing the 4.1 system, the rear may be difficult to achieve the same height as the front. My friend’s solution is to hang it on the wall. The satellite box is mainly responsible for sending out medium and high frequency signals, and it is easy to hear the direction. Therefore, when hanging on the wall, please try to keep the extension cable of the satellite box unit and the connection between the satellite box and the person parallel, when the satellite box is high When using the human ear, try to keep the downward inclination angle, and vice versa. The distance between the satellite box and the person should be as long as possible, and there should be no obstructions between this distance. After the medium and high frequencies are reflected, the direction will be chaotic, which will affect the positioning.
In order to make a beautiful appearance, many speakers design the shape to be very curvy. This often makes the panel of the speaker use more grids to sculpt this shape. What effect does this have on the sound? In the classic cubic design, the grille of the speaker is very simple, a frame with a layer of black gauze (other colors are also available), and if you want to make the grille into a curved shape, you cannot rely on a frame To achieve this, you need to add more grids to change the shape. In order to achieve a certain strength, the grids are generally thicker, which will seriously affect the quality of the sound. The sound generated by the unit will be scattered when encountering these grids. . We recommend removing these masks when using them.
In addition, some speakers use wire mesh masks for decoration, but they will vibrate at high volume and destroy the sound quality. If it is for sound quality, it is recommended to remove it.

Box shape, sound-absorbing cotton, sheet thickness
The shape of the cabinet shows that it is for a good-looking appearance, but more often it is for the needs of acoustic design. Like water waves, sound waves have the same characteristics of superposition and diffraction. The superimposed sound waves will change the frequency and become powerful when they reach a certain energy. You must have seen the example of scientists using sound waves to break glass. Although the sound waves in the box will not cause the speaker to malfunction no matter how superimposed, it is strong enough to make the box vibrate. Once the box vibrates, it will also emit Sound, thereby destroying sound quality.
In the speaker cabinet design, equilateral design should be taboo. For example, the shape of a square cube is easy to superimpose waves. Some speakers must be designed in a cube shape, so the only way to change the shape is to change the shape inside. The design principle of the speaker cabinet is to reduce these standing waves as much as possible, and make these standing waves lose their power as much as possible. The solution is to make the cabinet non-equilateral. A well-known example is the Hivi T200B with an inverted triangle design.
In addition, there are some methods that can help eliminate standing waves, such as filling the box with sound-absorbing cotton, and some speakers sticking wavy sponge on the inner wall of the box to achieve the same effect. Regardless of the design, standing waves cannot be completely eliminated. Making the cabinet difficult to vibrate is the last resort. The most direct method is to thicken the cabinet plate to make it difficult to vibrate. It will be used in the design of high-quality sound. To the thick board, this is also the reason why the high-end speakers are unusually heavy.

Dual frequency and full frequency band
I often hear the terms dual-frequency and full-band. What do they mean? On many X.1 satellite boxes, we only find one speaker, so this speaker is usually a full-band speaker. Full-band speakers, as the name implies, refer to speakers that can emit all frequencies, but in fact it is not the case. Unless the top full-band speakers, they are difficult to send out higher high frequency signals and lower low frequency signals, but they A bit wider than the general woofer frequency band.
Full-band speakers are not only widely used in multimedia X.1 speakers, but also in most car audio systems. In order to make the frequency band response wider, a two-way design is used in the exquisite design, which uses a tweeter and a continuous woofer to achieve a wider frequency response. As long as there is no error, the speaker with a two-way design will often appear Brighter, better resolution, but it does not mean that the frequency connection is correct.

Divider
The dual-frequency design is to use a tweeter and a woofer to work together, but the upper and lower limits of the two speakers do not naturally coincide. The lower limit of the tweeter frequency can reach about 3kHz, and the upper limit of the woofer can reach 5 -8kHz, there is a longer overlap. Only letting the two speakers cut off the combination in a smaller frequency range is the best policy, otherwise the superposition of waves will completely change the sound. In low-end designs, capacitor frequency division is often used. The biggest advantage of this design is low cost and average frequency division effect.
In the advanced design, a frequency divider is used to divide the frequency. A correctly designed frequency divider can perfectly control the connection of the middle and high frequencies. The function of the crossover is very important. It is the real soul of the speaker. The function of the crossover is not only to divide the frequency, but also to control the tone and other important functions. The appearance of the frequency divider is very easy to recognize. It has one set of signal input, and then two sets of signal output, which respectively transmit the processed signal to two speakers. The frequency divider generally uses one or more large inductors, which is a large copper coil. In recent years, electronic frequency division technology has emerged, which has a different working principle from traditional frequency dividers, but achieves the same effect.
How do you learn a lot? In fact, these are some of the most basic knowledge we should know. With them, we have certain references and standards when we read or evaluate the quality of a speaker by ourselves. You can take a look at it in detail!
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