What is a card speaker

Card speakers generally refer to speakers on the market that support or read SD, TF, etc. memory processors. Compared with traditional computer speakers and mobile phone speakers, the unique decoding function of card speakers makes it more consumer It is favored by readers, and because of this, it has become the decoding king in the audio empire. Many speaker brands produce card speakers. In addition to portable speakers, many multimedia 2.1 speakers also have card reading functions.

What is a card speaker

Structure and 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 equipment, 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 a constant magnetic field to vibrate the diaphragm and produce sound. It is characterized by fast response speed, low distortion, fine 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- and mid-frequency sound with a small 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. Free choice of songs and audio frequency, no need for complicated single skipping and channel changing　 3. Multiple charging functions

4. AUX IN external audio source input

5. With FM radio function, automatic channel search/save

6. High-efficiency digital power amplifier chip

7. Fully support hot swap, easy to use

8. USB sound card function (the AUX principle is the same, but the sound quality is better, and the circuit is independently amplified)

9. Good power amplifier effect

10. Compact and lightweight volume design, convenient for outdoor sports

Classification and characteristics
All-in-one 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 whether portable mini speakers or desktop mini speakers, there are many styles of integrated design.

2.1 Card speaker
Card speakers in the general sense are often limited to an integrated design. In fact, if they are classified according to their functions, card speakers should also have 2.1 card speakers, that is, speakers with card function added to 2.1 speakers. This kind of speaker also contains two pieces of multimedia and home video.

Buying skills
For the initial understanding of the card speaker, the steps of "watching, listening, and recognizing" can be used to identify: firstly view the technology and parameters, secondly listen to the sound quality, and thirdly recognize the brand.

A look at the process and parameters
At first glance, the craftsmanship is to judge the quality from the first appearance of the speaker, whether the production craftsmanship is accurate or not, fake and inferior products generally do not pay attention to these details, so a little care can be used to judge correctly. 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 represents the high frequency extension value of the card speaker. The higher the number, the better the audio 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 that the power amplifier required to drive the card speaker requires the battery 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 the high-fidelity speakers should reach 110dB or more, and the minimum signal-to-noise ratio marked by the card speakers is mostly between 70dB and 90dB.

main problem
1. Due to the specifications of the speakers, users who are used to PC 2.1 speakers may feel that the sound effect is not good enough;

2. It 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 actually tend to MP3, so this problem is not an important one.

history
origin
Speaking of the origin of card speakers, the industry generally believes that the popular and hot-selling card speakers extend to notebook speakers in 2008. With the introduction of notebook speakers, people began to pay attention to the market segment of card speakers\notebook speakers. In 2009, card-inserted speakers appeared in the industry, which could insert SD cards/U disks. 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 code. There is 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 high-end products.
Wooden Speakers:https://www.zeshuiplatform.com/