The rising interest in vinyl recordings, apart from nostalgic feelings, is fed by the whole range of human passions.
Firstly, these recordings return us to the great performers of the sixties, seventies and eighties who left a bright trace in music history. Secondly, they return us to such familiar live sounding which was taken as something self-evident thirty five years ago and became true valued only later, at the time of total domination of CDs.
Thirdly, the vinyl recordings return us to specific audio equipment, its use being a whole ritual indeed. The main parts of this equipment are a turntable, cartridge and phono preamplifier, which should be carefully matched, installed and properly connected with each other.
After that the vinyl disc is taken from its sleeve, placed on the platter and the needle put in the groove to start reproduction. The vinyl sound seems more natural than that of CD, it's immensely attractive, even if using the budget-level playback equipment. Of course, a more expensive, higher grade turntable and cartridge can provide a better performance, in the terms of tonal balance, channel separation and stability of the disc rotation speed.
An excellent example of combining an affordable price and high-end quality is the Rega P3-24 turntable (see Fig.1). Thanks to its optimal construction, the turntable creates all the necessary conditions for ideal capturing the material recorded on the disc, the main job here being done by the cartridge and particularly by the phono preamplifier.
The amplifier operation is often described as mysterious, and there are many factors the right signal at its output depends on. However, none of these factors alone can guarantee getting the desired pristine sound - neither ultra-low distortion and noise, nor an accurate RIAA correction and the best components. Decisive in this respect is the whole preamplifier design, its concept, originality and, maybe, even some elements of healthy mysticism.
Anyway, the final listening expertise will show how rich of live details is the sound produced by the given phono preamplifier, or correctly, the system "turntable - cartridge - preamplifier". This evaluation should be conducted by using the reference LPs with exemplary natural acoustic recordings, such masterpieces weren't rare 30-40 years ago.
The enjoyed vinyl tracks also can be saved in the digital form for further comparing them with the same tracks recorded via another vinyl reproduction system. Digital conversion in a 24bit/96kHz format with the help of a decent computer soundcard provides practically lossless quality, this means all the retrieved from the LP live content is preserved within the obtained wav-files.
Listening comparisons of the digitally recorded vinyl tracks aren't an easy procedure and they require careful preparation. The ear is very sensitive to the tiniest changes in sound, whether it is its loudness, frequency content or the presence of noise and live details.
Therefore, to exclude any incorrectness, the first that should be done just after opening the compared tracks in an audio editor (Sound Forge, for example) is to set their volume levels equal within 0,2dB. It's not difficult to perform visually, with the help of the tracks' graphically built peaks in the editing program (see Fig.2).
The next is to adjust, if necessary, the tonal characteristics of the tracks until matching them within 1dB. Only after that a difference in the live sound content and other subtle details can be revealed, the tracks being played alternately from the same chosen point and the moment of switching from one track to another being most demonstrative.
The difference in noise level takes place when analyzing the work of various noise reducing devices and programs, in this case the compared are an original and processed soundtracks. The noise problem in vinyl reproduction isn't such acute as in cassette playing, but recordings with the increased wideband noise sometimes occur on the vinyl discs issued in the sixties-seventies.
Whether this noise is originated from a noisy master tape or acquired in the course of vinyl pressing, it can be successfully cured by using a special automatic low-pass filter (see Fig.3). This device carries out an effective (12dB) and very selective noise reduction, leaving the signal content and, most importantly, its dynamics absolutely intact.
This noise reducer is universal, it's only necessary to set a proper threshold level of noise reduction for each concrete application. To demonstrate how it copes with the seemingly invincible cassette tape hiss, two samples containing the same audio track are offered for downloading. The track was originally recorded from my vinyl disc to cassette tape by using a Denon DRW-750A cassette deck. The record was then played, processed via the noise reducer and converted to the digital form, the finished file was labeled as "clean track". The file "noisy track" was obtained similarly, but with the noise reduction turned off.
The soundtracks should be compared when reproducing them via hi-fi or high-end audio equipment and good acoustic system, this condition is mandatory for all listening comparisons. By the way, these mp3 soundtracks also prove the ability of this so-called lossy format to sound perfectly.
The title of clean track and noisy track is "Duet Besedina & Taranenko - I Like"
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