The shape must be unique, not the male model design that can be seen all over the street. Because it is not easy to develop MP3 molds, and the design has certain patents, manufacturers will definitely position these products as high-end models and pay more attention to them. Tone matching is very important. Usually, senior designers will pay great attention to this aspect. It is not necessarily bright colors, but it is definitely a reasonable matching, which makes MP3 look more noble and elegant. It has a strong visual impact on users, especially those products tailored for fashion and beauty. Color is more attractive than any function. In addition, after advanced baking paint treatment, the shell will not fade easily, which can be seen from the color reflectivity of the shell.
In terms of material selection, metal is the best, followed by rubber, and engineering plastics are the worst. Of course, this does not mean that metal MP3 is a good product, but that metal is relatively more durable, looks more beautiful, and has more texture and grade. As the saying goes, "You will know if there are experts." You can roughly judge the material of MP3 by touching its shell to see if it is comfortable. Workmanship mainly depends on the subtleties of the product and the connection position between parts. If the shell is spliced urgently (especially the position of the battery cover), the buttons are soft and comfortable, and there is no burr and uneven body, which basically passes the test.
Lightweight can't be ignored. MP3 is a walkman. Even if the design is outstanding, it is inconvenient to carry or too big, it will lose the essence of "carrying". Mirror is a very popular design at present, however, the real nano-mirror can clearly reflect light and be used as a mirror. The biggest defect of the mirror is that once it is scratched, the scar will become very obvious, just like a beautiful woman with a torn face. Dante's DX-8 fuselage is streamlined, similar to an ellipse, with different curves at the upper and lower ends. It really looks like the plan of an egg, so it is named "Egg". Science is developing and progressing, so is fashion. The mobile phone we use has already entered the color screen era from a simple monochrome screen. Similarly, MP3 player, a typical representative of consumer digital products, has begun to enter the era of color screen, which I believe will inevitably become the mainstream of future development.
In terms of color effect, naturally, the higher the color number, the better. The screen material is LTPS (low temperature polysilicon) which is superior to TFT, and TFT (thin film transistor) which is superior to STN (super twisted nematic). As for the organic light-emitting diode (OLED) color screen, it has advantages in the dark, but it can't display complex pictures such as TFT and STN.
Due to the small size of MP3, the screen size will be greatly limited, and the bigger the screen, the better. Under the same size, the more displayed content proves that the screen resolution is higher, and the picture will be more delicate, which is also conducive to increasing the humanized graphic menu and making the operation method close to the daily Windows window habit. The most important chips are storage and decoding chips, and manufacturers usually don't disclose the information of storage chips. Of course, the chips of Samsung, Intel, Toshiba and other big manufacturers are of better quality, but unfortunately they can only be seen by disassembling the machine. Don't mention it. As for the decoding chip, it is mentioned in many MP3 evaluations, which not only determines the speed of audio processing, but also determines the special sound effects of MP3, including multiple eq and 3D sound effects. Of course, the decoding chip is also one of the most important parts that affect the sound quality, and the algorithm of APU (Audio Processing Unit) will play a decisive role in waveform restoration. Although MP3 format is lossy compression, the sound quality of MP3 will be greatly improved after using high sampling rate. However, MP3 audio files with high sampling rate need decoding chips to support high data flow, and the decoding chips used by cheap products are obviously insufficient at this time.
At the same time, the bad result of MP3 decoding chip is not only the sound quality degradation, but also the inability to support MP3 audio files with high sampling rate. For example, besides MP3, popular music compression formats include Microsoft WMA, ogg and MP3 pro, which can provide better sound quality at the same bit rate or provide smaller files at the same sound quality, but not all chips can support them. In addition, there is a good balance between sound quality and file size in MP3 VBR coding mode. Because of the variable bit rate, many chips can't support it well, and they can only decode according to the minimum bit rate or average bit rate of VBR coded files, which shows that the screen of the player can't walk accurately when timing, and the time of jumping back and forth is uneven. In addition, users who have the highest requirements for sound quality often choose the code rate of CBR 320kbs to compress MP3, but many chips only support MP3 with the maximum code rate of 256kbs, which cannot be decoded correctly.
Note that more advanced decoding chips are not used for newer products, and only those high-end products will use high-end chips. The decoders used in low-end MP3 are all products in stock several years ago, which leads to homogenization. They will sell with better headphones as a gimmick, but the inherent disadvantages will never change! At present, the most common chips in MP3 players on the market are Sigmatel, Actions, Sunplus (Sunplus), MosArt (Medium Silicon), Atmel, Telechip, st, PHILIPS, CRYSTAL and so on. These chips are mainly produced in Taiwan Province Province, China and South Korea, among which Actions is the product of mainland companies, and Sunplus and MosArt are the most common single-chip solutions among cheap MP3 players on the market.
First of all, Philips chips
Origin: Netherlands
If we must judge the best MP3 decoding chip on the market at present, it is undoubtedly Philips' chip. The decoding chip of Philips family has always been known as "full function, good sound quality and high price" in the industry.
Philips' decoding chip generally adopts BGA packaging technology, but the technology in this field is quite limited in China. In addition, the decoding chip of Philips needs to work with other control chip circuits, so the product cost is high. Therefore, manufacturers who use Philips decoding chips are often positioned in the middle and high price range, such as MPIO and IRIVER, two professional MP3 manufacturers in South Korea. One of the most important features of these two brands is the comprehensive use of Philips decoding chips in their products. Therefore, the sound quality and quality of their products are very high, which has become the goal pursued by MP3 fans all over the world.
Second, Sigmatel series
Origin: USA
If we want to talk about the market share of MP3 chips, the Sigmatel family in the United States certainly deserves it, but the quality of Sigmatel chips is always different. Generally speaking, MP3 of Sigmatel decoding chip will be quite satisfactory in sound quality, bright in sound, mediocre in midrange, lacking in bass sense and stiff in treble, and inferior to Philips and Telechips in music performance.
Third, the lark chip
Origin: Korea
At present, the domestic button machine uses SKYLARK chip from South Korea's ECT company, but it does not support WMA. The price is similar to that of STMP34 10, with more functions. Larks are characterized by low power consumption and clear and pleasant sound quality. The recording generates files in MP3 format, and the compression bit rate is optional; Coding direct recording function, the compression bit rate can be adjusted as needed; Built-in FM radio can be used in China, Japan and Europe, and the received clips can be recorded in the player; Chinese, English, Korean, Japanese and other languages; Synchronous display of song title, ID3 and lyrics (supporting synchronous display of Chinese song title and lyrics); Independent file deletion function, easy to use; A-B auditory function; Memory capacity query, you can query the memory capacity. Needless to say, the masterpiece using KYLARK chip is Dante DX-8. We already know too much about eggs, so we won't go into details here. When we regret that it doesn't support WMA file format, we can't help but deeply appreciate the designer's wonderful creativity.
Four. ATMEL chip
Origin: USA
ATMEL is a leader in DSP and MCU industry. AT89C5 1ND 1X series chips are DSP+MCU mixed solutions for embedded multimedia applications specially developed for mp3 industry. Using this chip, MP3 is integrated with USB and MMC is embedded with very small system software, with complete functions. The USB function only needs15kbyte firmware code. The power consumption of this MP3 decoder and hardware interface controller is very low.
Verb (abbreviation for verb) silica
Origin: Taiwan Province Province.
MOSART chips in Taiwan Province Province have simple functions and are generally used in low-end products, such as LCD monitors or SD card players. Dual-chip structure (CPU and decoding chip are separated). The sound quality is distinctive, the bass is good, and the tenor is average.
Intransitive verb ATJ2085 torch power supply
Origin: Zhuhai
Torch Force's ATJ208564 pin package is highly integrated. Supported formats are MP3, WMA, WMV, ASF, FM, and the chip is cheaper. At present, many mainland manufacturers choose this ATJ208564PIN, but its disadvantage is that the sound quality is average and barely audible, and the performance of FM needs to be improved. Headphones include two parts. One is the output power of MP3 itself. High output power (two headphones add up to more than 20mW) can drive some high-impedance high-end headphones and make the sound quality more perfect. Second, the quality of the earphone itself, judging people by their appearance is an inevitable way, and the appearance of excellent headphones will certainly not be bad there. The most important thing to note is that those headphones are claimed to be the OEM of a famous leather factory for publicity. In fact, most headphones are not really branded products, but the appearance is similar, and the inside is not the same thing at all. People are afraid of being famous and pigs are afraid of being strong. Once a headset model has established a famous brand effect, many headset manufacturers will follow suit to produce similar products, and even MP3 manufacturers have begun to set foot in it. So don't blindly listen to the description of the business or some press releases. The best way is to listen to it yourself. To tell the truth, most MP3 headphones on the market are not so good. Even the high-end products still let us down. Only those really high-end products will have headphones that are more acceptable. If you really pay attention to the quality of MP3 headphones, you can only choose from the top models of various brands.
By the way, even the real OEM headphones, their product performance and quality are inevitably not as good as the retail version of headphones. The retail version of the product should take into account both brand image and profit, and the requirements for the product will be much higher. Relatively speaking, OEM is only incidental, and some standards do not meet the requirements of the retail version, so there is no need to care too much. In short, don't be too superstitious about OEM headphones attached to MP3. It's better to buy some brand-name headphones around 50- 150 yuan, which is definitely better than the so-called OEM products. MP3 has more and more functions. Like PDA and mobile phone, it is developing to multi-function, absorbing the functions of other products as much as possible to increase the selling point of products. When buying, you should start on demand and don't blindly pursue versatility. The more functions, the more expensive they are, and when you buy them back, you will find that many of them are not used at all.
● Mobile hard disk: The computer directly recognizes MP3 as mobile storage, which can store all kinds of files except music.
● Firmware upgrade: Solve the known software and hardware faults after product release and add new functions.
● Folder browsing: Different songs are stored in folders and played as a unit, so it is not necessary to put all MP3s in the same directory, which improves the ease of management.
● Multilingualism: Chinese Simplified, Chinese Traditional, Korean, Japanese and English are mainly supported, and some models even have 26 languages.
●A-B Repetition: Reading a passage repeatedly is convenient for learning a foreign language.
● Text reading: Usually only large-screen MP3 players have this function, which can be read as an e-book. Some products also support the text format of PDA. If the firmware capacity is sufficient, you can also download various Chinese and foreign fonts. Auto-scrolling is also useful. When turning pages automatically or automatically, the background light is always on, which not only saves the trouble of turning pages by yourself, but also completely makes up for the shortcomings of small display screen. You can even listen to MP3 while reading, just like a PDA with simplified functions.
●TTS(text-to-speech), which directly converts text into text through MP3. The machine sound has no change in tone and rhythm, which sounds strange, but it is very suitable for lazy people who don't want to read.
Dictionary: an English-Chinese dictionary for translation. Note that MP3 control keys are limited, and it is not easy to input English words.
● Automatic recording function: With SAD (Sound Activity Detector), you can set the mute duration and record only when there is sound, which saves both storage space and playback time.
● Remote recording: AGC (Automatic Gain Control) can be used to adjust the sensitivity and recording quality (low, heavy and high), which is suitable for long-distance external recording, such as meetings.
●FM: Listening to the radio, many products can preset several channels without having to tune them every time.
●FM recording: Transfer the radio content to MP3, and some products also have FM recording! You can enter which day of the week, when and how many hertz of channels to start recording. You won't miss it because you are busy with your favorite radio programs or foreign language learning programs. You can record it and listen slowly.
●EQ setting: setting of sound effects. Almost every product has several preset sound effects settings, such as normal, rock, jazz, pop and classical. Some MP3 players also support custom sound settings, which users can customize according to their own preferences. For products without LCD display, these EQ settings almost don't exist, only curing their own sound mode. This is a bit cruel to some friends who are particularly loyal to personalized music effects.
● Direct recording: encode and compress external audio sources (CD/MD walkman, home stereo, computer) into music files and store them directly on MP3. Due to the poor performance of the built-in coding chip of MP3 player, the sound quality is not as good as that of the music files compressed by computer.
● Clock: The time setting can be entered as month, day and hour, which can be used as a watch.
● Alarm clock: A timed alarm clock can be set, which can not only beep when earplugs are installed, but also beep when microphones are installed. The alarm clock will also take effect when earplugs are not installed.
● Timing shutdown: The timing shutdown time can be set between 0 ~ 180 minutes. Of course, you can also set the automatic shutdown without operation for 0 ~ 60 minutes, which is most convenient for listening to songs before going to bed at night.
● Picture Browser: You can not only browse the photos you have taken, but also enjoy the pictures downloaded from the computer. Because the screen of MP3 is small and the resolution is relatively high, you will feel beautiful when you look at the picture, but most screens are limited in proportion. If the scale is wrong, it will be deformed and cannot be displayed normally.
● Digital camera: Like the early cameras of mobile phones, it adopts10-300,000 pixels 1/5.5 CMOS lens. The main disadvantage of CMOS is its slow brightness sensing, so the shooting effect is better in a well-lit environment. The biggest advantage of CMOS is its small size, which is most suitable for MP3 walkman. The camera itself also has many functions, such as digital zoom and multi-effect shooting. Early MP3 players used No.5 (AA) or No.7 (AAA) batteries, so you can buy them at will, and the price is relatively cheap (0.5-5 yuan). If it is a rechargeable lithium battery (10- 15 yuan), the battery life is long, and the playing time can reach more than 10 hour. Carrying extra batteries can meet the demand for 2-3 days. You can't always plug your ears with headphones.
What is important here is the lithium battery, which can be divided into two types: detachable and non-detachable. The detachable lithium battery is very convenient to use and can be replaced at any time. In addition to charging after connecting the computer with USB cable, you can also charge with the attached power adapter. Its large capacity and special discharge mode can guarantee the playing time of more than 30 hours, which is enough for three AA batteries. However, there are few MP3 players using detachable lithium batteries, and they will not exceed the model of 10 on the market. The nameplate on the battery will indicate the battery working voltage, safety matters, warranty period and other information, as well as the maximum output current and charging time, so as to facilitate re-purchase. But buying a detachable lithium battery is also quite expensive (150-around 200 yuan). Because of its small size, it will be very painful if you accidentally lose it.
In contrast, non-removable lithium batteries have no loss problem. MP3 players using this battery are usually quite small, and even the LCD screens of power-saving homes are not available. But they can still play for 6-8 hours. Its biggest problem is that it often needs to be recharged. If you use it for a long time, you have to carry a charger with you, which is really troublesome. If you have all kinds of digital products, the weight of the charger alone is enough for you. In addition, pay attention to its service life. Many people don't cherish the use of lithium batteries. Don't run out of lithium batteries every time or use low power. Many people have this misunderstanding. In fact, lithium batteries should maintain 40% to 60% capacity, of course, they can still be fully charged. Lithium batteries need to be charged as needed, and each time they are used up, they will be filled with the "patents" belonging to the early Ni-MH batteries. Lithium batteries only need to be charged once a month (less than 20% is used or the equipment is automatically turned off). The omen is that the use time is getting shorter and shorter until it can't be recharged at last. Once the non-removable lithium battery is damaged, it can only be repaired and replaced by the manufacturer in the early stage. Usually only manufacturers have this special battery with unique shape, and the replacement price is about 100 yuan/block. After the product has passed the warranty period, the maintenance fee will be paid, and the long-term investment will be doubled. But now you just need to go to a shopping website like Taobao to buy a battery. Non-original batteries are often cheaper or even larger than original batteries. It's normal to replace the battery by yourself. All you have to do is find a disassembly tutorial. At present, most MP3 players have the function of flash disk, so the speed is very important when transferring files or music. USB 2.0, also known as high-speed USB, has a transmission speed of 480mbps = 60mb/s. In other words, theoretically, the first 5MB MP3 of 12 can be transmitted within one second. As for IEEE 1394 (Firewire), the speed is 400M bps = 50MB/ s, and the first 5MB MP3 of 10 can be transmitted in one second. For 256,512mb products, copying songs is just a breeze, even if it is a GB hard disk MP3, it will not be too slow. But if you use USB 1.0, its speed is only 12M bps = 1.5MB/ s, and it takes 3.3 seconds to copy a 5MB song. It's really a pity to wait for flowers, especially on the hard disk MP3. Not many people have such good patience.
Be sure to check whether MP3 supports USB 2.0 before buying. At present, there are about 30-40 products supporting USB 2.0 on the market, which are generally relatively new models. But not many products will clearly mark this function on the shell. We can only find it through the manual or the packing box, or ask the dealer directly. If you are really not sure, the best way is to try it on the computer. Since most motherboards already contain USB 2.0 interfaces, Win XP will prompt you to find related devices. MP3 is a highly integrated high-tech product, which not only contains the same hardware as the traditional walkman, but also contains a lot of software technologies, so the maintenance of MP3 is different from the traditional portable one. Among them, the author will discuss some common MP3 faults and troubleshooting methods. (See the figure below on the Resources website.
1) cannot play the music player.
In case of such a problem, we should first determine whether some music can't be played or all music can't be played. If you can't play all the music, you can try formatting the player first. Some players who don't have drives should pay attention to the formatted file system. Most players only support FAT 16 because the player capacity is not large. If the wrong file system is used for formatting, the file may not be played, crashed or started. If only some music can't be played, first check whether there are any problems with those music files that can't be played, especially some music files downloaded from the Internet. Although many of them have MP3 extensions, they actually only have MP2 format. At present, many players on the market can't play MP2 files, especially some high-end players. The easiest way to distinguish MP3 from MP2 is to use WinAMP, open the music file with WinAMP, then double-click the file title, and then look at one of the MPEG information: MPEG 1.0, if it is followed by layer3, it is MP3 file, if it is layer 1, it is MP2 file.
2) collapse
Because most players can update their firmware, and such player firmware is also stored in Flash, the firmware may be lost or wrong in normal use. If the player runs abnormally or can't be started, you should try to update the firmware first, and then start the machine for maintenance. Because there are many types of players, the specific firmware update steps should be carried out according to the player manual. First of all, the USB problem
The first thing I saw was an IHP 120 of iRirver. Due to the reverse connection of the USB cable in front of the chassis, the USB interface of the player is burnt out, and music cannot be transmitted through USB, but other functions are normal. Fault analysis: If the USB cable is connected backwards, it is equivalent to that the USB interface power supply is connected backwards. Generally speaking, the reverse connection of power supply will cause serious problems, but IHP 120 did not use bus power supply when it was designed, so it did not cause a large area of fault points. At the same time, the USB interface of general USB devices is protected by a protection circuit. Therefore, before disassembling the machine, it is necessary to analyze the problem of the protection circuit. After opening the shell, we found that a capacitor at the USB interface was burnt out: the withstand voltage of this capacitor was 6V (forward), and it was found that this capacitor had been short-circuited after measuring with a multimeter. After welding this capacitor and connecting it to USB interface, I found that the computer can find the hardware and everything is normal. Because this capacitor is used in USB interface for filtering, this circuit is generally designed to enhance the anti-interference ability under bad conditions, which is necessary for electromagnetic detection. But if you don't install it, it won't have other adverse effects on the machine, and you can remove it when you repair it yourself. Of course, if it is specially for maintenance, it would be even better. Because this machine is for a friend's maintenance, and the friend's requirements in this respect are not very high, so we removed this capacitor and thoroughly cleaned the surrounding circuit boards with anhydrous alcohol, and the machine maintenance was completed. The following figure shows the cleaned machine: you can see that the position of capacitor C 16 is empty, but it does not affect the use. Of course, sometimes the problem of USB interface is not necessarily that the capacitor is burnt out, because most machines have two inductors (some of which are resistors) at the entrance of USB power supply. Although the inductance itself can play a certain filtering role, it will be burned out when the current is relatively large because of the very small wire diameter, which can protect the machine to a certain extent. If nothing happens when USB is connected to the computer, we can check whether there is something wrong with it. Generally, machines will design them near the USB interface: the two dark components in the enlarged part are inductors. During maintenance, we can use a multimeter to measure their resistance, which is generally below10Ω. If the resistance is too large or infinite, we can solve the problem by replacing them. Of course, under amateur maintenance, it can be used directly by short circuit. Summary: When the USB connected computer does not respond, first check the inductance (resistance) of two current limiting devices near the USB interface (although it has the function of filtering, it is mostly used for current limiting protection). If it is an open circuit, it can be replaced directly, and amateur maintenance can be directly short-circuited. Then check whether the capacitor connected in parallel with the USB interface is short-circuited. If it is a short circuit, it can be replaced with the same capacity or similar capacity, and amateur maintenance can be abandoned.
Second, a channel can't work properly.
There is no sound in a certain channel, or the sound is very weak, which is also a common problem. Because MP3 players all use 3.5mm audio sockets, and the sockets are directly soldered on the circuit board, this problem will occur on some machines that fail to be soldered after repeated plugging and unplugging. If a certain channel is silent or the sound is intermittent, you can replace the earphone first to determine the fault point. After it is confirmed that it is a machine problem, disassemble the machine directly and re-weld the socket pin with an electric soldering iron. If welding is carried out at the socket grounding point, sometimes the sound will sound hollow. However, the maintenance of this problem is relatively simple. But sometimes the solder joint is in virtual welding, so the solder joint looks good after it is removed, but at this time it is best to add some rosin (or other flux) to the solder joint for repair welding. You can find the fault point in your spare time and directly find the master who repairs home appliances. Summary: When the sound of the player is intermittent or weak, replace the earphone first to determine the fault point. If there is no problem with the earphone, the problem can generally be solved by re-welding the plug pins with an electric soldering iron after disassembling the earphone.
Third, explain the problem.
The screen of most MP3 players is connected to the circuit board through a flat cable. If words appear intermittently on the screen, you can check whether the jumper is loose first, or unplug it and try again. At the same time, note that this kind of patch panel cannot be directly unplugged. There are two small handles on both sides of the patch panel. After pulling out the handle with a screwdriver, you can easily unplug the cable. The same is true during installation. Make sure the handle is outside, plug in the cable, and then press the handle. When unplugging the cable on the LCD, first pull the handle on the insert outward in the direction shown by the arrow, and then the cable can be easily pulled out. Summary: When there is something wrong with the LCD display, you can first check whether there is something wrong with the cable on the LCD, or try to unplug the cable. Of course, there are also some machines whose cables are welded on the circuit board. This kind of liquid crystal must be replaced as soon as something goes wrong, and it is best not to solve it by itself.
Four. Internal connector
MP3 players are all composed of two or more circuit boards, which are mostly connected by inserts. After long-term use, this plug-in may be in poor contact, resulting in various failures, and it can't be turned on at all in serious cases. Of course, such problems are generally relatively simple to maintain. You can unplug the plug-in directly, and then wash it with a brush dipped in anhydrous alcohol. After repeated cleaning, the poor contact of the contact can be removed. (Use two circuit boards connected by patch cords) (Soak alcohol with a brush and wash it repeatedly) Summary: When a machine using multiple circuit boards fails, you can check whether there is any problem with the internal patch cords first, and sometimes cleaning can get twice the result with half the effort under uncertain conditions. Other problems: In fact, most player faults can be eliminated by the above methods. Of course, other problems also occur from time to time, such as chip burning, component failure and so on. But once the chip burns out, you need to use special equipment to replace the chip, and then you must ask the maintenance department for help.