Comparison Denon DCD-900NE vs Marantz CD6007

The number of discs the player's built-in changer can hold.

Changers in this case include any devices that allow you to install several discs in the player at once. The possibilities of such models may even include the formation of playlists from tracks on different discs and automatic switching between the latter during playback. Changers can have different designs: a “carousel” with several recesses, a cassette with discs stacked in a stack, etc. Even two separate slots in one player in this case also belong to the changer.

The convenience of "multi-charge" is obvious — it allows you to keep at the ready several times more music than in a single-disk player. At the same time, the changer significantly complicates the design of the device, and this not only affects the cost, but also increases the likelihood of interference. Therefore, this function is rarely found in high-end CD players, and even then, most often — in the form of the mentioned separate slots for discs.

The model of the digital-to-analogue converter (DAC) installed in the CD player.

The DAC is one of the most important components of any modern CD player. It is this module that is responsible for converting digital data recorded on an optical disc into an analogue audio signal that is fed to an external device (amplifier, speakers, etc.). Accordingly, the characteristics and overall quality of the DAC largely determine the sound quality in general. Knowing the DAC model, you can find detailed data on it — characteristics, reviews, test results, etc. — and evaluate how the capabilities of the converter meet your requirements.

The presence of a built-in power amplifier in the design of the CD player.

This feature allows you to connect passive speakers to the player without using external amplifiers, which take up extra space and are often very expensive. In addition, some of these models combine passive speaker jacks with RCA outputs (see below) and can simultaneously drive active and passive speakers (for example, to create a multizone). On the other hand, when buying such a model, the user cannot choose the "amplifier" himself — he has to rely on the choice of the manufacturer; at the same time, built-in amplifiers are also considered less advanced than external ones. Therefore, for fans of the highest quality sound, who prefer to independently select all the components of the audio system, the presence of a built-in amplifier may turn out to be a disadvantage, not an advantage.

Sampling frequency of a digital-to-analogue converter (DAC) installed in a CD player.

A DAC is an indispensable element of any system designed to reproduce digital sound. Such a converter is an electronic module that translates sound information into analogue pulses fed to speakers through amplification stages. The technical features of such a conversion are such that the higher the sampling rate, the better the signal at the output of the DAC, the less it is distorted during conversion. And in the case of CD players, this indicator must also be no lower than the sampling rate of the reproduced digital sound — otherwise the device simply will not be able to "digest" digital data from the media. So, an indicator of 92 – 96 kHz allows you to listen to CD-Audio (sampling frequency 44.1 kHz), but for DVD you need at least 192 kHz. In the most advanced DACs, the sampling rate can be 384 kHz. The latter, however, is rare: in most cases, high frequency is not critical, and such electronics are expensive.

Another indicator that determines the overall quality of the digital-to-analogue audio signal converter. For details on the converter, see "DAC Sampling Rate"; here we note that the bit depth is standardly expressed in bits, and the higher it is, the more accurately the signal at the output of the DAC corresponds to the original signal and the less distortion is introduced into it. In the case of CD players, 24 bits is considered the minimum necessary and at the same time quite sufficient; higher values — 32 bits — are rare, only in premium-level equipment.

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.