Other than price and looks, the audio quality is an important factor that a consumer should not neglect when purchasing a digital audio player. To gather figures for this player, we sent the Philips Key Ring MP3 Player down to a professional audio lab for testing. After putting the player throught a series of rigid tests, we got some results back to show to the readers here.
Philips Key Ring MP3 Player Results
- CROSSTALK: 42
- STEREO CHANNEL UNBALANCE: 0.13
- TOTAL HARMONIC DISTORTION: 0.025
- SIGNAL NOISE RATIO (SNR): 81.5dB
*Results serve only as an unofficial reference.
The results clearly indicate that the Philips Key Ring MP3 Player offers above average audio quality. The quality is pretty impressive for a device this small but it still lacks when compared to the likes of other HDD-based MP3 players. There is a possibility that audio quality was traded off for a much more compact design.
Well, maybe most of you reading this do not understand these values here. Afterall, not everyone who browses VR-Zone is an electronics/signals expert. Knowledge is wealth afterall. Now here is an explanation of the meaning for the terms above from Audio/Video 101 Dictionary
Audio distortion resulting from information in one audio channel leaking into the signal of another channel. The channel into which the signal leaks is distorted. This distortion can harm stereo imaging and the overall sound field if it is sufficiently bad. Crosstalk can also occur between components such as the signal from a tape player leaking into the signal from a CD player causing distortion in the CD signal. Crosstalk is a particular problem with radio in which one channel may interfere with another (such as when you are listening to you favorite radio station and you can hear in the background a different announcer’s voice or a different song which is on a different channel).
S/N Ratio (Signal-to-Noise Ratio)
Maximum output of an electronic device or recording medium compared to its noise floor or level of background noise. S/N ratios are measure in decibels (dB), and larger numbers are better. A S/N ratio of 100 dB means that the maximum signal output is 100 decibels above the noise floor, or the point at which the signal will be obscured by noise (low-level hum and other electrical interference that is part of the component).
Digital media such as CDs and DVDs tend to have higher signal-to-noise ratios than analog media such as VHS tapes and audiocassettes. Solid state amplifiers (those based on transistors instead of vacuum tubes) tend to have high signal-to-noise ratios. When comparing audio/video components, a higher S/N ratio is better (of course the difference between a high 100 dB number and a 105 dB is not a deciding factor as both figures are excellent and will cause no problems in ordinary listening).
Total Harmonic Distortion (THD)
Distortion derived from the creation of harmonics (multiples of a base frequency signal) in an audio system adding additional frequency peaks to the output.
Harmonics are multiples of the original signal being reproduced by an audio system. For instance, if a signal at 2 kHz is being produced by an audio system, harmonics would be located at 4 kHz, 6 kHz, 8 kHz, 10 kHz and so on with each progressive frequency being smaller than the one before. This type of distortion affects the audio signal by adding to it frequencies that were not included and not meant to be reproduced.
Total harmonic distortion figures are derived by feeding a pure sine wave into an audio component and then measuring the amplitude of the fundamental (the original pure sine wave being input) and its harmonics. Amplitude is the height of a sign wave from the base level to its peak. Signals with greater amplitude are louder or more powerful. The amplitudes of harmonics are smaller than that of the original signal (fundamental). By dividing the amplitudes of the harmonics by the amplitude of the fundamental (the original pure signal), a THD figure can be generated. Look for low THD figures preferably of 0.5% or less.
Stereo Audio Channel Unbalance
Discrete, single grouping of audio information played through a sound system resulting in a steady flow of sound from one single source; for example a stereo system with two speakers has two channels, one left channel and one right channel. Unbalances arises due to difference in level between left and right channel.