Comparison Denon DCD-720AE vs Denon DCD-1520AE

Types of media, data formats and signal sources supported by the CD player.

— CD-Audio. The standard used for recording traditional Audio CDs. The CD-Audio format provides a sampling frequency of 44.1 kHz, 16-bits bits depth and 2 stereo channels. The bitrate of such a recording is 1411.2 kbit/s, which allows for very high sound quality (for comparison: in the case of MP3 files, 320 kbit/s is considered very good, and for lossless recording in the FLAC format, 950 kbit/s is quite enough With). And the maximum total track length for a full-size disc is just under 80 minutes. Thanks to all this, Audio CDs do not lose popularity among audiophiles, and this format is supported by all modern CD players (which, in fact, explains the name of this class of equipment).

- MQA-CD. An audio format that uses MQA (Master Quality Authenticated) technology from the American company Meridian Audio for audio encoding. It allows you to preserve the original audio quality while compressing files and restoring them - in the case of standard CD media, MQA-CD provides sound that is as close as possible to high-quality audio formats.

- MP3/WMA. MP3 and WMA are the most popular audio file formats used in modern consumer electronics. They can be recorded on optical discs, USB drives, and built-in storage devices. At the same time, in audio equipment, including CD players, support for both of these sta...ndards is most often found, and in terms of key features and sound quality they are similar - which is why MP3 and WMA in this case are combined in one point. Of the mentioned features, it is worth noting, first of all, that when encoding sound, these standards use the so-called. lossy compression: individual parts of the audio stream are transmitted with reduced accuracy, or even drowned out altogether. Thanks to this, the files are small in size; and the trimmed parts are selected in such a way that the impact on the overall sound quality is minimal, and when listening on ordinary household audio equipment (such as computer speakers or a portable player), the loss of quality is practically unnoticeable. But on Hi-Fi and Hi-End audio systems (and CD players are precisely designed for such systems), the difference in sound can be clearly audible, although here a lot depends on the subjective characteristics of the listener.

- SACD. The Super Audio CD format is a further development and improvement of the “regular” CD-Audio described above. Thanks to the use of new technologies, the number of audio channels available for one track has increased to 6 (which makes it possible to record not only stereo, but also multi-channel 5.1 audio on SACD), and the sampling frequency has increased to 2822.4 kHz (64 times higher than on Audio CD). In addition, sound can be recorded with different parameters - for example, part of the disc in 5.1, part in stereo 2.0. On such a disc, with several recording zones, the maximum sound duration reaches 109 minutes, and if there is only one recording zone - 180 minutes. It is worth considering that the SACD format itself cannot be read by conventional CD drives. And although “hybrid” SACD media, compatible with conventional CD drives, have become quite widespread, all the capabilities of this format can only be realized on a compatible player.

- DVD. An optical disc format that replaced CDs. In the case of CD players, support for this format usually implies the ability to play sound recorded using the DVD-Audio standard. This standard provides a bits depth of up to 24 bits, a sampling frequency of up to 192 kHz and the ability to work with 6 audio channels (5.1, except for recording at the maximum sampling frequency). And models with DVD drives that support MP3/WMA can usually read these files from DVDs. The capacity of a standard single-sided DVD is 4.7 GB, there are double-sided and double-layer media; and the duration of DVD-Audio recording depends not only on the type of disc, but also on the sound quality.

- AM/FM radio. The ability to use a CD player to receive AM and FM radio broadcasts in analog format (support for digital broadcasting is indicated separately - see below). The FM band allows you to transmit stereo sound in fairly good quality; True, the transmission range is limited by line of sight, but this is quite enough to cover even a fairly large city. Because of this, this standard is used by the vast majority of urban music stations. AM, in turn, has a much greater range, but is inferior in sound quality and does not support stereo broadcasts. Therefore, most of these stations are “talk”, and the standard itself is much less popular than FM - to the point that some models of CD players can only be equipped with FM tuners, without AM support (but not vice versa).

- DAB radio. Possibility of using a CD player to receive DAB digital radio broadcasts. The practical advantages of digital radio broadcasting over analogue include good range and high sound quality, due, in particular, to the almost complete absence of interference: the sound is either heard clearly and cleanly, or disappears altogether. In addition to the original DAB, the improved DAB+ standard is on the market; “plus” tuners are capable of receiving “regular” DAB broadcasts, but not vice versa. In any case, it is worth considering that in the CIS countries this type of radio broadcasting is still only in its infancy and has not yet become widespread. Therefore, before buying a CD player with a digital tuner, it doesn’t hurt to make sure that such broadcasting is available in your region (or at least planned to be launched in the near future) - otherwise you may overpay for unnecessary equipment.

— Network streaming audio. The ability to play network streaming audio with a CD player - in other words, playing music directly from the Internet, from specialized services like Last.FM or Grooveshark. The name “streaming” is due to the fact that during playback there is a stream of data through the network connection, which is converted by the player into sound; Simply put, each file is played directly from the network, there is no need to download it to local storage like a flash drive. And the main difference between such sound and Internet radio (see below) is that in this case the customer controls the playback. Essentially, working with streaming audio is similar to working with a regular player, except that the content being played is not in the player itself, but on a network resource. This feature by definition requires a connection to computer networks; Most often, a Wi-Fi module (see “Interfaces”) or a LAN connector is used for this purpose.

— Internet radio. The ability to use a CD player to receive and play Internet radio broadcasts. This feature is similar in many ways to the network audio described above - in particular, it requires a network connection to work, and the data is transmitted in streaming format; however, here the broadcast is similar to regular radio broadcasts and is controlled not by the customer, but by the radio station staff. In fact, many large stations broadcast their programs not only on traditional airwaves, but also via the Internet; There are also specialized projects that broadcast only on the Internet. In general, the choice of Internet programs is much wider than for conventional radio broadcasting - after all, such radio has no range restrictions. And the players themselves may provide additional tools for managing such broadcasting - for example, catalogs, search by genre, language, etc.

Wired and wireless interfaces for connecting external devices provided in the design of the CD player.

— Airplay. A technology for transmitting multimedia data over a Wi-Fi wireless connection (see below). Developed by Apple and widely used in its portable devices, in particular the iPod touch, iPhone and iPad, but is also available for equipment from other manufacturers. Allows you to broadcast audio files to compatible devices (in streaming audio mode, see "Playback" for details), as well as images, text data, and even video. The presence of AirPlay in a CD player will make it possible to connect devices supporting this technology to it for direct playback, as well as display information about files — song title, artist name, etc.

— Wi-Fi. A wireless interface that can be used for two purposes: connection to computer networks (including the Internet) and direct connection with smartphones, tablets and other external equipment. The first option is convenient for implementing network functions — streaming audio, Internet radio(see "Playback"), AirPlay (see above), DLNA(see below). Connection to computer networks can also be carried out through a wired LAN interface (see below), however, Wi-Fi is more convenient due to the lack of wires and the ability to wor...k through obstacles (including walls) at a distance of several tens of metres. And connection with external devices can be provided primarily for remote control of the player.

— Bluetooth. A wireless technology developed for the direct communication of various devices with each other. Provides a distance of up to 10 m (in specific cases — and more, but this option is not relevant for CD players). Specific Bluetooth capabilities may vary depending on the protocols supported by the device. In the case of players, this function is usually used to broadcast audio to wireless headphones or Bluetooth speakers; this connection is convenient due to the absence of a wire, but the sound quality can be noticeably lower than with a wired connection. The reverse option may also be provided — broadcasting sound from a smartphone, tablet, etc. for playback through the player and acoustics connected to it; but this application, like others, is extremely rare.

— LAN. A standard interface used for wired connection to computer networks — both to "local computers" (with or without Internet access), and directly to Internet providers. Accordingly, the presence of such a connector in a CD player implies support for network functions — for example, DLNA or Internet radio (see "Communications"); specific networking capabilities vary by model.

— RS-232. It's a COM port. A specialized connector used to connect the player to a computer and control its settings from a PC. Such control can be more diverse and at the same time simpler and clearer than working with a standard panel or remote control.

— DLNA. A technology used to connect various electronic devices into a single digital network with the ability to directly exchange content. Devices for which support of this standard is claimed are able to interact effectively regardless of the manufacturer. A DLNA CD player can, for example, play music from a computer hard drive in the next room. Connection to the Network can be carried out both wired (LAN) and wireless (Wi-Fi) way; both options are described above.

— USB (type A). This connector is used to connect various USB peripherals to the device. In the case of CD players, we are most often talking about "flash drives" and other external drives: when they are connected to USB Type A, direct playback of the content recorded on such a drive is possible. Usually, this connector is installed on the front panel of the player, and some models of connectors may have more than one.

— USB (type B). This interface allows you to connect a CD player to your computer as a peripheral device. Such a connection can provide a wide variety of possibilities: playback of sound from a PC through the player and acoustics connected to it, control of the player's settings through the service programme, firmware updates, etc. (the specific set of capabilities depends on the model).

— Card reader. A slot for reading memory cards — most often the most popular modern SD format, although theoretically other options can be provided. This feature allows you to play music directly from memory cards. Such media are convenient because card readers are installed in almost all modern laptops, many tablets, smartphones (albeit for smaller cards), etc. However it must be borne in mind that even among SD cards there are several generations that are incompatible with each other; therefore, before using a card reader, you should definitely clarify which cards it is designed for.

— Connecting an iPod/iPhone. The presence in the CD player of special functions for working with portable Apple devices — iPod players, iPhone smartphones, and in most cases — iPad tablets. Such functions may include, for example, switching tracks on the player and managing playlists from the player's remote control; anyway, they make life much easier for those who would like to listen to music from the "apple" technology. Note that in the case of CD players, to connect such equipment, it is usually not a special dock that is used, but a regular general-purpose USB type A port (see above), with which the device is connected via a special cable. Occasionally there are models equipped with external docking stations (which, however, are most often also connected via USB).

The range of audio frequencies that a CD player can reproduce. In general, this parameter determines how full the output bandwidth is, whether too high or too low sound is cut off. However, it is worth noting here that the human ear is able to perceive sound only within the range of 16 – 20,000 Hz (deviations from the upper threshold in different directions are possible, but small, and it decreases with age). All modern CD players cover this range, therefore, in the case of such devices, the sound frequency indicators are reference and practically do not affect the sound. And impressive numbers like 2 – 40,000 Hz, 5 – 60,000 Hz, etc. — this is a kind of "side effect" of the design of a high-quality device; manufacturers use these numbers for marketing purposes, but again, they do not affect sound quality. Also, do not forget that actually audible frequencies are also limited by the characteristics of the speaker system, external amplifier and other equipment connected to the CD player. For example, speakers with a lower frequency range of 150 Hz will “cut off” all lower frequencies, and it doesn’t matter what the lowest bass the player can produce is 16 Hz, 20 Hz or 50 Hz.

The ratio between the level of the useful signal and the level of extraneous noise at the output of the player.

This indicator describes the total amount of extraneous noise (of any origin) that affects the sound quality: the higher the signal-to-noise ratio, the less such noise and the clearer the sound, which is especially important for Hi-Fi and Hi-End systems. The minimum indicator for CD players is 85 – 90 dB, indicators up to 100 dB can be considered good, up to 110 dB — good, more than 110 dB — excellent.

The dynamic range of a CD player.

Technically, dynamic range is the logarithm of the ratio between the maximum input signal at which the level of distortion is low enough (tolerable) and the sensitivity of the amplifier. In a simplified way, this parameter can be described as the difference between the minimum and maximum sound levels that the device is capable of reproducing with high quality. The higher the dynamic range value, the better the device handles with sound that has significant volume differences, such as orchestral parts.

Note that when playing different sound standards (see "Playback"), the dynamic range of the player will also be different — for example, for SACD its value is usually much higher than for Audio CD. CD players typically list the highest value that gives the best impression of the device's performance. However, manufacturers often specify for which type of digital audio the dynamic range data is given.

The coefficient of harmonic distortion (harmonics) output by the CD player.

This parameter, along with the signal-to-noise ratio described above, characterizes the overall sound quality of the player. It is calculated by dividing the total sum of harmonics by the value of the main signal at a reproduced sound frequency of 1 kHz, and is expressed as a percentage. Significant levels of harmonics lead to deterioration in sound — from a general feeling of "roughness" and "excessive density" of the sound to the appearance of clearly audible noise; accordingly, the lower the harmonic distortion, the better. In relatively inexpensive CD players, this figure is measured in tenths of a percent, in top models it may not exceed several thousandths of a percent.

Outputs provided in the design of the CD player (in addition to analogue connectors for connecting general-purpose acoustics — they are described in separate paragraphs below).

— Coaxial S / P-DIF. Interface for transmitting sound in digital format. Allows you to work with multi-channel audio up to 7.1 format inclusive. Technically an electrical variation of S/P-DIF; differs from the optical variety described below, on the one hand, by greater sensitivity to electromagnetic interference, and on the other hand, by a less delicate connecting cable. Note that this interface uses RCA connectors and a coaxial cable (hence the name). However, unlike "regular" analogue RCA (see below), in this case, all audio channels are transmitted over a single cable, and the cable itself must be shielded — when connected through a regular wire, there is a high probability of distortion due to external interference.

— Optical. A modification of the S/P-DIF standard (see above), which involves signal transmission via a TOSLINK fiber optic cable. Being identical to the coaxial interface in terms of audio transmission capabilities, the optical connection is at the same time completely immune to electromagnetic interference, which makes it possible to achieve extremely high signal fidelity. The disadvantage of this connection is the fragility of the cable — it does not allow sharp bends and strong pressure, whic...h can damage the fiber.

— Balanced digital (AES/EBU). The AES / EBU standard itself can use different connection interfaces, however, XLR connectors are usually used in audio equipment. However, unlike the "regular" XLR output (see below), this interface transmits audio in digital format, not analogue. A common feature of these standards is a balanced connection, which provides noise suppression due to the characteristics of the cable itself, has a positive effect on sound quality and at the same time allows the use of fairly long wires. AES/EBU is considered a professional interface; such an output can be useful, for example, for connecting a CD player to a high-end external amplifier.

— Trigger. A service output used to turn on other components of the audio system (for example, an amplifier) at the same time as a CD player. When the player is turned on, this output sends a signal to the input of the controlled device and wakes it up, saving the user from having to press extra buttons. This is especially useful if the device being controlled is located in a hard-to-reach place.

— Headphones. Output for connecting conventional audio headphones. There is no single standard for such a connector, however, the vast majority of both players and “ears” use one of the varieties of the Jack type connector — full-size 6.35 mm or mini-Jack 3.5 mm. At the same time, in stationary audio equipment, including CD players, the full-size version is quite common, but 3.5 mm plugs are very popular in headphones — they can be connected both to the “native” jack and to the 6.35 mm jack, through a simple adapter (many models even come with adapters. Anyway, the ability to listen to music through headphones will be useful in cases where loud sounds are undesirable — for example, at a late time when others are sleeping, or if there is a small child in the house.

— Subwoofer. Separate output for connecting an active subwoofer — a specialized low-frequency speaker with its own built-in amplifier. The need to use subwoofers is due to the fact that general-purpose speakers do not cope well with low frequencies, as well as some acoustic features of these frequencies. And a dedicated output for such a speaker greatly simplifies the connection: this output is supplied with a filtered low-frequency signal, so you can do without crossovers and other external equipment (the only exception is a passive subwoofer, which will require an external amplifier for this connection).

— Control output (IR). Auxiliary output used in remote control systems. With this connector, the CD player's built-in IR receiver can be used to control other audio system components from the remote control, such as an amplifier in another room, out of range of the remote control. In fact, the player in such cases plays the role of a remote sensor, receiving commands and transmitting them through the control output to another device. Note that the very presence of control inputs and outputs does not guarantee the compatibility of various devices, especially if they are produced by different manufacturers; the nuances of sharing should be clarified according to the official documentation.

— BNC. By itself, BNC is a type of connector related to coaxial; similar in size to RCA, but differs in internal dimensions and mounting features. In CD players, a connector with such an output can be used both for outputting digital sound, similar to coaxial SP-DIF, and for working with special equipment for synchronizing digital sound pulses. The specific use case should be specified separately, there are both at once. Note that in the second case, the BNC output is responsible for switching the synchronization signals received by the CD player from an external clock generator to other devices in the audio system. For more information about synchronization, see "Inputs — BNC".

— Power output. This output is a power connector installed directly on the body of the player. From such a connector, you can power another component of the audio system — for example, an external amplifier or active acoustics; in some cases, this may be more convenient than connecting such components to the network separately. Please note that power plugs are usually different from standard 230 V sockets and are not compatible with plugs for such sockets.

Inputs provided in the design of the CD player.

Note that the specific use of the inputs used for audio transmission varies by model. So, in some cases, it is possible to process sound with the built-in means of a CD player (adjusting the balance, frequencies, etc.); in others — signal conversion from analogue to digital format or vice versa (for example, broadcasting sound from the optical output of a Blu-ray player to acoustics), in others — real-time recording of the input signal, etc. But for service connectors, the purpose is quite clear.

Specific types of inputs can be as follows:

— Mini-Jack (3.5 mm). A standard connector widely used in modern audio equipment and other electronics, mostly portable. Technically, the mini-Jack input can be used for different types of signal, but in fact in CD players it most often plays the role of a line interface and is mainly used to connect the mentioned portable equipment — for example, audio players.

— Trigger. Service input used to automatically turn on the CD player. If you connect this input to the trigger output of another audio system component (for example, an audio receiver), this component, when turned on, will supply a control signal to the player and wake it up. In other words, the control device and the player will turn on at the same time, at the touch of a button — this is more convenient than turning on th...e equipment separately.

— Coaxial S/P-DIF. Interface for transmitting sound in digital format. Allows you to work with multi-channel audio up to 7.1 format inclusive. Technically an electrical variation of S/P-DIF; differs from the optical one described below, on the one hand, by greater sensitivity to electromagnetic interference, on the other hand, by a less delicate connecting cable. Note that this interface uses RCA connectors and a coaxial cable. However, unlike the "regular" analogue RCA (see above), in this case, all audio channels are transmitted over a single cable, and the wire itself must be shielded — when connected through a regular wire, there is a high probability of distortion due to interference.

— Optical. A modification of the S/P-DIF standard (see above), which involves signal transmission via a TOSLINK fibre optic cable. Being identical to the coaxial interface in terms of audio transmission capabilities, the optical connection is at the same time completely immune to electromagnetic interference, which makes it possible to achieve extremely high signal fidelity. The disadvantage of this connection is the fragility of the cable — it does not allow sharp bends and strong pressure, which can damage the fibre.

— Balanced digital (AES/EBU). Digital audio output in balanced format. This format provides noise immunity even with a long cable length, which is especially important in professional applications; in fact, the presence of an AES / EBU input indicates a rather high class device. Technically, this interface can use different connectors, but CD players usually use XLR jacks and plugs. From the "normal" (analogue) XLR, such a connection differs, in fact, in a digital format.

— RCA. Similar to the RCA outputs (see above), in this case we mean an interface for transmitting an analogue audio signal in the “one wire per channel” format, and one input is a pair of connectors for the left and right stereo sound channels.

— Control input (IR). Connector for connecting an external infrared remote control receiver. When properly placed, such a receiver will allow you to use the remote control even in places where the signal from the remote control cannot reach the main (built-in) sensor — for example, in another room. Note that not only individual sensors can be used as external receivers, but also other components of the audio system that are compatible with the remote control — for example, receivers or tuners.

— BNC. A type of coaxial connector used for various purposes. However, in this particular case, the BNC input is most often provided for working with an external clock generator responsible for timing the digital audio signal pulses. The need to use such equipment is due to the fact that when transmitting a signal between the components of an audio system, for various reasons, deviations of pulses in time may occur. This phenomenon is called "jitter". Deviations, it would seem, are very small (measured in picoseconds), but even such a small thing can significantly degrade the sound quality and increase the noise level. To avoid this, premium audio systems can use an external clock generator: by transmitting service pulses to other components, it sets the “general rhythm” under which the data packets move, and prevents desynchronization. To connect such a generator, a BNC input is usually provided. However, in some models this connector can also be used as a digital audio input, similar to the S / P-DIF described above.

— XLR. Formally, XLR is the name of a connector that has a round shape, several pins and a retainer to hold the plug in the socket. However, in this case we are talking about a very specific interface: an audio input with a three-pin plug used for balanced connection of an analogue audio signal. The peculiarity of this connection is that the cable itself plays the role of an interference filter, which allows you to transmit an audio signal with high reliability even over a rather long wire. At the same time, such reliability is rarely required for ordinary consumer audio equipment, so XLR is considered to be a professional connector. Note that, like RCA, in this case, one channel of sound is transmitted through one connector, and the standard XLR input consists of two jacks (for a stereo signal).

The power consumed by the CD player. Usually, unless otherwise noted in the notes, this refers to the power during normal operation. Note that the actual power consumption at a particular point in time may differ from this indicator — for example, when a model with its own power amplifier (see "Built-in amplifier") is operating at low volume or vice versa, when playing a song with sudden volume jumps. However, when organizing the power supply of the audio system, it is necessary to focus on this indicator.

Note that the power consumption cannot be lower than the power of the built-in amplifier (if present, see above). However, some manufacturers may go for tricks — for example, indicate power consumption only in preamplifier mode. As a result, the power consumption stated in the specifications is significantly lower than the actual value when the amplifier is turned on (and sometimes even lower than the rated power of the amplifier alone). In such cases, the actual power consumption can be estimated by adding the claimed power consumption to the power of the amplifier and taking a margin of 20 – 30% for energy losses due to non-perfect efficiency of electronic circuits. For example, for a 50 W model with a 2x60 W amplifier, this value will be about 200 ... 220 W (50 + 2x60 \u003d 170, plus a loss correction).