Signal to noise ratio
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.
Harmonic distortion
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.
Power consumption
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).
