The era of CDs, and therefore of all related technologies, is slowly but surely coming to an end. However, there are still lovers of the classical performance of music or films. Just like gramophone records. For reading CDs, special devices are used - CD players. The article provides an overview of such devices, their characteristics and interesting features.
Appearance story
Oddly enough, but scientists have achieved success in the laser processing of CDs before they developed the first personal computers. Two Russian inventors, Alexander Prokhorov and Nikolai Basov, made a hand in this discovery . It was they who created the basis for the technology - the first cold laser. For which they received the Nobel Prize. Philips and Sony began to engage in the further development and creation of full-fledged reading devices and, in fact, the media themselves.
The main engines in the promotion of CD technology were IT giants - Microsoft and Apple.
For a long time, Sony and Philips could not come to a common denominator in the issue of the amount of stored data. Sony initially offered a 100mm disc, while Philips offered 115.
According to one version, the disk capacity should have been enough to record Beethoven’s symphony No. 9 on it. Such was the installation, which eventually formed the basis of the standard CD.
As a result, both companies agreed that a standard of 120 mm, a duration of 74 minutes and a frequency of 44.1 kHz will be adopted as a standard.
Volume development
Work on compact disks did not stop, and in 1996 in Japan a new standard appeared - DVD. Its minimum size is 4.7 GB. At that time, this was enough to record a full-fledged film in acceptable quality. The improvement of this technology has led to the possibility of using both sides of the disk, as well as several working layers on them. This allowed to increase the total volume to 17 GB.
Parish MP3
Probably everyone who has ever downloaded music from the Internet has heard about the MP3 format . This format burst into the world of sound and turned everything upside down.
In general terms, MP3 is a codec, that is, a mechanism for compressing and decompressing audio data using a special algorithm. It allowed recording music on CDs with a total duration many times longer than the standard 74 minutes. In particular, about 200 songs in MP3 format could “enter” a regular CD. At the moment, it is the most popular and well-known type of music file and composition file.
However, to play this type of special players were required with the appropriate codec. So there were players of CD MP3 disks.
How is reading from a CD?
The CD player reads data using a laser beam. The principle is based on taking into account changes in the intensity of light reflection from the surface. Thus, the alternation of the depressions on the base of the disk is counted.
The rotation of the disk is due to the engine. The reading head also does not stand still. With the help of servos, it moves from the center of the disk to its edge.
At the start of operation, the device reads data from the header, which is located at the beginning of the disk, that is, where its diameter is smaller. With the help of the information received, the system finds out where a particular section of a song, film or data is located. And it can quickly position the read head in the right place.
Sometimes the reading head is contaminated for one reason or another. And since it is located inside the device, there is no way to arrange manual cleaning.
Therefore, special cleaning discs of the CD player are used. They can be both dry and wet. A special cleaning element is applied to their surface, which during rotation touches the lens, thereby cleaning it.
However, judging by the feedback from users, this approach does not always cope with its task and many recommend spending time on parsing the device and cleaning the item manually.
The first CD players
The founder of the series was the CDP-101 from Sony. At one time, it was very expensive. Reading was carried out by an optical sensor with a semiconductor laser by means of digital reading.
From the first conveniences, it is noted that it was possible to quickly select the desired composition and its position. As an indicator, a simple display was used, on which the time of the musical work was displayed.
A drive tray was used as a disc feed. The entire control process was carried out using ten physical buttons.
This unit marked the beginning of industry standards for CD-ROM devices.
"Estonia LP-001 Stereo"
The first domestic CD player was Estonia LP-001. It was produced by the Tallinn Punane RET factory.
He possessed all the functions inherent in this type of player - reading music tracks and a quick transition from composition to composition.
Of course, the expression “domestic” is a little wrong, since most of the components were still Philips - the leader in this industry at that time.
Modern player market
Nowadays, devices for playing CDs can still be found on the shelves of electronics stores. True, now they do not recognize. A modern CD and DVD player is a multifunctional, complex technical device with many "chips" and features.
Onkyo C-N7050
The appearance of the player resembles a classic device from the 90s. However, its "filling" suggests otherwise.
The device is equipped with USB ports for connecting other devices. In this way, you can stream sound from more mobile gadgets directly to this CD player.
There is also an Ethernet port for connecting to a computer.
The list of supported formats is quite extensive - MP3, AAC, FLAC, WAV and other well-known types.
Philips EXP2540 / 02
Bright representative of the family of portable CD players.
Made in an elegant white design. Supported formats are MP3, CD, CD-R, CD-RW, which it can play in various modes. For example, in random order or repeat one song.
As a sound source, standard 3.5 mm headphones are used. The LCD display, which displays information about the album number, battery level, functions and track time, is responsible for the indication during operation.
The Magic ESP function allows you to play songs without jerking during shock or shaking. It is based on the caching of parts of the track to avoid interruption of sound.
Panasonic SL-SW405
Another portable CD player. Its distinguishing feature is its resistance to falls and shocks. The rubberized case reliably protects from dust and even water.
LCD display displays current information about the tracks, their duration, battery status.
It has a built-in equalizer that allows you to adjust the sound for the "gourmet" of pure sound.
Of the interesting features is the ability to program a sequence of tracks.
Two AA batteries are used as power sources. This compact CD player is ideal for listening to music on the go, walking, jogging and traveling.
Future CD and user reviews
As such, there is no future for CDs. Technologies evolve and new methods of data transfer and storage appear. Flash drives are already conquering the market. Their volumes, speed and reliability are many times higher than CD parameters.
In this regard, users are increasingly evaluating CD players against the backdrop of new developments. For example, they often complain about the lack of wireless connectivity in stationary CD players. But they were created just for this - to listen to music from a CD. There is no need to create other sources of sound, especially such as a network. But some manufacturers are still introducing this feature into their products, making the classic CD player the usual intermediary for transmitting audio.
Another important requirement of users for CD players, in particular portable ones, was the presence of the so-called Anti-Shock system. That is, the mechanism of protection against shake, which could unexpectedly interrupt the composition or even throw it to the next. A number of reviews were also associated with this at a time when CD = players were a fashionable novelty, rather than an archaic device.