Structure composition
The card speaker is mainly composed of three parts: speaker, cavity and power amplifier.
Speaker
The speaker (speaker unit) is the weakest device in the card speaker device, and it is the most important component for the card speaker effect . The speakers of the card speakers are mostly electrodynamic speakers, which use the interaction force between the voice coil and the constant magnetic field to vibrate the diaphragm and produce sound. It is characterized by fast response speed, low distortion, excellent playback sound quality, and good layering.
Cavity
The cavity is used to eliminate the acoustic short circuit of the speaker unit, suppress its acoustic resonance, broaden its frequency response range, and reduce distortion. The purpose of the card speaker has a cavity-mainly to prevent the sound wave signals on the front and back of the speaker diaphragm from directly forming a loop, causing only high-frequency sound with a short wavelength to be transmitted, and other sound signals are superimposed Offset.
Power amplifier
The power amplifier is mainly composed of inductance, resistance, capacitance and other passive components to form a filter network, and the audio signals of each frequency band are sent to the speakers of the corresponding frequency band for reproduction. Its characteristics are low production cost, simple structure, suitable for amateur production, but large insertion loss, low efficiency, and poor transient characteristics.
Product features
1. Directly play MP3 format in U disk or memory card, etc.
2. Freely select songs and audio frequency, without complicated single jump Music, channel change
3, multiple charging functions
4, AUX IN external audio input
5, with FM radio function, automatic channel search/save Taiwan
6, high-efficiency digital power amplifier chip
7, fully support hot swap, easy to use
8, USB sound card function (AUX principle is the same, But the sound quality is better, and the circuit is amplified independently)
9, good power amplifier effect
10, compact and lightweight volume design, convenient for outdoor sports
Classification and characteristics< /h2> Integrated design
The integrated design is the main feature of the card speaker. The integrated design is an effective way to simplify the connection and use of the speaker, giving people a more concise feeling, so no matter how portable Mini speakers are desktop mini speakers, and there are many styles with integrated design.
2.1 card speakers
Generally speaking, card speakers are often limited to one-piece designs. In fact, if they are classified according to their functions, card speakers should also have 2.1 speakers. Card speakers, that is, speakers with card function added on the basis of 2.1 speakers, this kind of speakers also contains two pieces of multimedia and home video.
Purchase skills
For the initial understanding of the card speaker, the steps of "watching, listening, and recognizing" can be used to identify: firstly, the process and parameters, secondly, the sound quality, and thirdly. Recognize the brand.
Yiguan craftsmanship and parameters
Yiguan craftsmanship is to judge the quality from the first appearance of the speaker, whether the production craftsmanship is accurate, fake and inferior products are generally not Pay attention to these details, so you can judge correctly with a little care. The technical parameters of the card speaker are nothing more than frequency range, output power, and signal-to-noise ratio.
The frequency range is generally 90Hz～20KHz. 90Hz represents the extension value of the card speaker in the low frequency direction. The lower the number, the better the low frequency response of the card speaker: 20KHz means the card speaker can reach The higher the number, the better the high-frequency characteristics.
The output power is a reference indicator of the card speaker. It is expressed in watts. This indicator does not indicate the quality of the speaker. It only indicates the power amplifier and battery required to drive the card speaker. Need to have the required output power.
The signal-to-noise ratio refers to the ratio of the output signal voltage of the amplifier to the noise voltage output at the same time. It is often expressed in decibels. The higher the signal-to-noise ratio of the device, the less noise it produces. Generally speaking, the larger the signal-to-noise ratio, the smaller the noise mixed in the signal and the higher the sound quality of the sound playback. Otherwise, the opposite is true. The signal-to-noise ratio should generally not be lower than 70dB. The signal-to-noise ratio of high-fidelity speakers should reach 110dB or more. The minimum signal-to-noise ratio marked by card speakers is mostly between 70dB and 90dB.
Second listening sound quality
The card speakers are mostly made of plastic. The smaller the material density of the speaker shell, the greater the vibration generated by the cabinet when sound is emitted. From this perspective To a certain extent, it is difficult for card speakers to achieve subwoofer effect, which is also a common problem of almost all card speakers. However, the so-called extremes of things must be reversed. Although the card speakers are slightly inadequate in terms of bass, the performance of high and intermediate frequencies can be very good. With different design structures and different cavity sizes, the sound quality of card speakers may still vary greatly.
Three recognized brands
Good card speakers have well-made gold-plated or chrome-plated brand marks. If the trademark does not have a registration mark, there is no anti-counterfeiting certification mark on the outer packaging, and there is no inside the packaging. Warranty cards, most of these three-free products are suspected of being counterfeit or inferior.
Main problems
1, Due to the speaker specifications, users who are accustomed to computer PC 2.1 speakers may feel that the sound effect is not good enough; p>
2, may be due to the use of some public molds, and there is generally no headphone jack. In fact, this problem is easy to solve. It may be that this interface is not added from the perspective of production cost control. But from the point of view of the main purpose of portable speakers, it should be portable and loudspeaker. If you put too much emphasis on the headphone jack, you will actually tend to MP3, so this issue is not an important issue.
History
Origin
Speaking of the origin of card speakers, the industry generally believes that the popular and hot-selling card speakers extend to notebooks in 2008 Speakers. With the introduction of notebook speakers, people began to pay attention to the market segment of card speakers\notebook speakers. In 2009, a card audio system appeared in the industry, that is, SD cards/U disks could be inserted. At that time, wooden cabinets were the mainstay. However, the improvement of the appearance design of the rear cabinet has also produced great changes. There are no fixed design standards for speakers, batteries, etc., which has caused many after-sales problems. In the second half of 2009, some planned manufacturers began to produce digital audio systems with plastic casings.
It has been several years since the appearance of the card speaker in 2012, and it has developed into a digital speaker capable of supporting USB, SD/MMC card and radio functions in 2012. It has powerful functions and has gradually become a fashion symbol. Codename. There is a demand, so there is a market. However, the popular digital audio system has found that the sound quality is average, and it should be said that there is a certain gap between it and the high-end products.
Current situation
The monthly market capacity of card speakers is about 20 million units. However, in 2012, manufacturers and channels have more than one million units in inventory. Why is this status quo? It is because a large number of card speaker manufacturers have poured in. Due to the low threshold, there are as many as 200 card speaker manufacturers in Shenzhen for a period of time, while other non-brand manufacturers mainly rely on price wars to attract attention, and quality can not be guaranteed. If the normal profit of a factory cannot be guaranteed, coupled with the pressure of some follow-up repairs, it will be sooner or later to close the door, the most obvious in the first three months.
Development trend
In 2012, digital card speakers went bankrupt every day. If the cost of a product is 40 yuan, it will be sold to the channels at about 20 yuan. Many channels are opportunistic. Greed for cheap in order to make short-term quick money and gladly accept this kind of product disrupting the industry at the same time, it is also a stage disaster for many digital speaker manufacturers committed to the brand, and many so-called brand manufacturers’ market decline is also affected by this. The early reshuffle has arrived. It is estimated that it will be clear at a glance in mid-2012 to see who can stick to the end.
From a technical point of view, its development trend is:
First networking
Increase wifi function to achieve networking
Second Intelligently increase software functions
such as learning machines, repeaters, etc.
Thirdly emphasize the radio function
Because the radio function is very cheap, it can be realized. Multi-band radio chips, such as AM, FM, and SW functions, have already appeared. Multi-band reception can be realized by configuring the magnetic micro-aerospace line.
The fourth is to strengthen the mobile TV function
The introduction of frequency band TV antennas allows this type of terminal to receive analog and digital TV functions.
The fifth equipped Bluetooth module
Using high-quality Bluetooth 3.0+EDR, the maximum reception can reach 10 meters, and the voice is echo-free, which is your unique choice for driving.