Comparison Pro-Ject CD Box E vs Pro-Ject CD BOX S3

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.

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 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 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.