Regarding the portable usb speaker, do you really know how to play?
Why add a portable usb speaker? Is the bigger the portable usb speaker better? What should I do if the low frequency is pasted together? How to adjust the subwoofer phase? For practical purposes, we will explain it today.
What is a portable usb speaker subwoofer?
First of all, let's take a brief look at the subwoofer. It is a common name or abbreviation for everyone. Strictly speaking, it should be: subwoofer. Subwoofer is actually a name for bass music in electronic music. This term was developed innovatively for the first time, and the term "subwoofer", a local characteristic term, was pioneered by Mai Lan (now Maibo).
In terms of audio analysis that can be heard by the human ear, it is composed of heavy bass, bass, low midrange, midrange, midrange, treble, treble, and super treble, which has the effect of strengthening the syllable rhythm.
Simply put, the bass is the basic framework of the sound, the midrange is the flesh and blood of the sound, and the treble is the detailed reflection of the sound. The human ear can hear the portable usb speaker is extremely limited, but other human senses will feel it, this is the feeling of shock! The heavy bass only exists in a specific program source and needs to be restored. With it, it can make the restoration of the program source more solid, without it, it gives people the feeling of lack of power and energy.
In order to restore realistic multi-channel sound effects, a portable usb speaker is essential
The main function of the portable usb speaker is to improve the sound quality, increase the bass texture of the sound, and effectively strengthen the effect of the syllable rhythm. With it, it can make the restoration of the program source more solid, without it, it gives people the feeling of lack of power and energy. For example, in a movie theater or in reality, we can feel the shock of the power and energy when the plane takes off, but if our home theater is not equipped with subwoofer speakers or the configuration is unreasonable, people will not be able to feel the shock, but That's it. Subwoofers are mainly divided into two categories, they are PASSIVE and ACTIVE. At present, there are many three-piece "3D" satellite systems with subwoofer speakers and two small main speakers on the market. Only one subwoofer is used in this system, so the portable usb speaker is L The +R signal has a stereo effect above the crossover point.
Do not judge the quality of the portable usb speaker by the size of the portable usb speaker
Many users believe that the size of the monomer on the subwoofer must be the bigger the better. In fact, this problem involves factors such as the drive power of the subwoofer itself, the type of cabinet, the efficiency of the unit and the instantaneous performance. Although the large-size monomer can push the air with a larger area, and thus produce a more substantial low frequency, but the large-size monomer has a heavier cone weight than the small-size monomer, and I want to push it to a stronger low frequency , The first part of the amplifying circuit must have a stronger output power.
Moreover, the instantaneous performance of large-sized monomers is often not as good as that of small-diameter monomers. Therefore, the speed of low-frequency transmission is often not fast enough compared with smaller-diameter monomers, and it may even produce sound "tailing". The phenomenon. Therefore, most of the portable usb speakers that use large-size monomers only provide greater low-frequency content, but they cannot be as light and agile as small-diameter monomers in the sense of speed. According to the characteristics of such a single unit, a manufacturer once used multiple small-diameter woofers to form a subwoofer with the same or larger area as the large-diameter unit. Control and instantaneous performance, coupled with multiple cells arranged into the same air drive area as the large cell, form a perfect subwoofer that is fast and can generate the same energy as the large-diameter cell. However, such portable usb speaker have to be very sophisticated in terms of their monomers, cabinets, and AV power amplifiers. Regardless of the actual effect, the price may not be acceptable to ordinary consumers.
The left and right channel woofers are powerful, do I need to add a portable usb speaker?
The power amplifier system cannot determine whether the mid and low range (especially the low frequency part) of the whole combination is sufficient based on the size of the single speaker unit. The reason is that the normal multi-channel system will mostly cross the frequency band below 80Hz or 90Hz of the response frequency band. Give the subwoofer the responsibility. Of course, if you don’t have a portable usb speaker, you can also set the front left and right channels to full range from the power amplifier menu. However, such a setting of 5.0 channels and 7.0 channels will definitely cause a greater burden on the front left and right channels and the amplifier circuit of the power amplifier itself. Even if you use a high-efficiency left and right channel and a high-power output power amplifier, the low frequency performance should not be much better than the built-in power amplifier, and the portable usb speaker using individual monomers is much better. Furthermore, the exclusive dedicated active subwoofer can independently adjust the volume, crossover point and phase, and individual cabinets can be freely selected according to the space and speaker placement. For the mid-low range of the entire multi-channel system The adjustment part also has more flexible adjustment space than using 5.0 channels.
Although the bass is non-directional, the portable usb speaker pays attention to phase
The most basic phase refers to the sound wave Simply put, it is the vibration of the air. When we hear sound, the air pressure changes what we hear. It is like the ripples splashed by a stone falling into the water, and the sound is made by air movement. As in water, these movements cause ripple effects. Waves are composed of crests and troughs. These make our eardrums vibrate, and our brain converts these thoughts into sounds. When we record sound, the diaphragm of the microphone is basically copying the behavior of our eardrum, vibrating with these waves. These crests make the microphone's diaphragm move in one direction, while their troughs move in the opposite direction. Or to put it another way: a complete wave form from the peak to the trough and back to the origin, the positive and negative sine wave formed is a total of 360 degrees, that is to say, when the wave is half of the phase of 180 degrees, it is exactly 0 degrees. And 360 degrees form an inverted waveform. Simply put, in the placement and adjustment of the subwoofer, when the portable usb speaker and the left and right channel speakers sound in the same direction, the sound phase of the two should be close to the same phase. If the subwoofer is placed in a position where it "hides" with the speakers, the subwoofer will form a 180-degree antiphase with the left and right speakers. At this time, if the phase of the subwoofer backplane is not set to 180 degrees (inverted), not only will the subwoofer low frequency always be emitted from the back of the sound field, or part of the frequency band between the subwoofer and the speaker will be It will cause phase inconsistency, and even the increase or disappearance of some low frequency bands due to the overlap or offset of the phase.
Many causes of phase offset or overlap are caused by the environment and space. In addition, because the sound phase of the five-channel speakers is different, it is impossible for the subwoofer to only choose the front and back positions. Sometimes, in order to avoid the formation of low-frequency standing waves, we may place the subwoofer at two-thirds of the side wall and hit it diagonally. In this way, the phase adjustment part of the portable usb speaker will also be complemented by the above factors. It becomes very complicated.
In the face of the above-mentioned complex factors, when we adjust the positive and negative phases of the subwoofer, we can follow the low-frequency sense of the listening position. In other words, when we play a low-frequency drum performance or electronic dance music, you can sit in the listening position, and then switch the positive and negative phases of the subwoofer in turn, as long as you can feel it in the listening position To a strong low-frequency effect, such a phase can make you feel the low-frequency phase.
Because of this, many portable usb speaker will traditionally only be equipped with positive and negative (0/180 degrees) phase switching functions, and upgrade them to have 0-180 degrees continuous adjustment or 0-360 degrees multi-step selection. The purpose is to provide audio system users with the ability to adjust the appropriate phase angle without succumbing to the position of the subwoofer.
There are two extremes in the audio world. High-end high-fidelity audio equipment consists of many different devices. They sound unbelievable, but at the same time they take up a lot of space and are not portable.
At the other end is a Bluetooth speaker. As long as it is fully charged, you can take it to any place to play music via Bluetooth. Although the sound fidelity will never be too good, they are cheaper and more convenient.
