These two electron microscopic images of the grooves of a vinyl disc (LP increased 500 times, left) and a compact disc (CD increased 20,000 times, right) were obtained by Chris Supranowitz, a researcher at the Institute of Optics of the University of Rochester For me, the image of the vinyl grooves has the beauty and “heat” of the analog, compared to the coldness of the compact. The vinyl image shows the technique used to record music in stereo: the groove is asymmetric in such a way that «the lateral movements represent the sum of the stereo channels and the vertical movements represent the subtraction or subtraction of both signals»
The dirt that is appreciated is inevitable since it is microscopic dust glued by static electricity to the surface. That dirt is the main source of the “frying” of vinyl sound, which many still long for. You can also see another impressive photograph that shows us the groove of a vinyl by increasing it 1000 times in the source of both images: «Record grooves under an electron microscope,» SynthGear, February 17, 2010 [seen in “Vinyl under the electron microscope, »Thanks to« The groove of a vinyl increased 1000 times «]. As one of the meneantes said, “so imperfect and is the best music support … that nostalgia.”
What sounds better, a vinyl or a CD?
Vinyl fans claim that the sound of the CD is “cold” and lacking dynamic range, while the defenders of the CD claim that the main defects of vinyl are “crackling” and harmonic distortion. The human ear has a dynamic range of about 120 dB, although a room not quietly soundproofed has a noise level of the order of 20 dB, and above 100 dB most people feel discomfort. A vinyl record has a maximum dynamic range of about 65 dB and a music CD of about 96 dB (live music between 100-120 dB). Now, another thing is how the music is recorded [see below the “volume war”].
Apart from psychoacoustics, which studies how we perceive the music we hear, a technical and objective comparison can be made, such as that presented by Chris Tham, “Dynamic Comparison of LPs vs CDs – Part 4,” Audioholics, Oline A / V Magazine, September 02, 2004. Chris used his sound card (Audiotrak Prodigy 7.1) and the Cool Edit Pro analysis program. He took several music vinyls from his collection from which he had a CD or DVD-Audio copy and cleaned them as best he could. He could with a cleaning kit (freshly bought). He digitized the sound offered by his 96 kHz sampled vinyl player with a 24-bit resolution, did the same with the (analog) sound offered by his CD (or DVD) player, and compared them to the “real” digital sound of the CD (or DVD) obtained with Exact Audio Copy (or DVD Decrypter) that is sampled at 44’1 kHz with a resolution of 16 bits.
The results are interesting.
The first thing to remember is that the audible spectrum of the human ear is usually said to be from 20 Hz to 20 kHz, although it depends a lot on the person and age (young children usually hear somewhat higher frequencies and lose this quality with the age). Most people in adulthood do not exceed 17 kHz, but there are those who reach 30 kHz (in fact there are people who hear ultrasonic whistles to train dogs). Music on a CD is sampled at 44’1 kHz to ensure perfect reproduction (by the Nyquist-Shannon sampling theorem) of frequencies up to 22’05 kHz, beyond what a person with a standard ear can hear. In addition, high fidelity standards require “perfect” reproduction at these frequencies. Even so, many tweeter (treble loudspeakers) from the sound boxes of quality music equipment reach playback frequencies close to 30 kHz. Formats such as DVD-A or SACD that allow very high sampling rates (up to 192 kHz on the DVD-A) are only for professionals who want to “play” with the sound in a studio; studies on human acoustics indicate that a normal person cannot distinguish between the sound produced by a DVD-A and that of a CD [a famous study is EB Meyer, DR Moran, “Audibility of a CD-Standard A / D / A Loop Inserted into High-Resolution Audio Playback, »J. Audio Eng. Soc. 55: 775-779, 2007, but there are many others who conclude the same).
For the most famous song in the soundtrack of “Carros de fuego” by Vangelis, he compared the exact digital copy (EAC) of the CD (1984), the reproduced CD and the LP (1981) reproduced. The result is that the dynamic range of the LP is smaller than that of the CD (played), which in turn is smaller than that of the digital copy (as expected the CD player alters the recorded sound). The basic cause is the background noise in the LP reproduction. However, when he studied the background noise (in a silence), as shown in the figure above, he observed that the CD noise goes from -88 dB to -108 dB (due to the sound card) sharply around 20kHz; however, the noise of the LP does not show this jump and is lower than that of the CD for frequencies between 1 kHz (-84 dB) and 10 kHz (-96 dB). The reason that the dynamic range of the CD is better than that of the LP is that the noise of the LP at low frequency is much higher below 500 Hz (up to -50 dB). Therefore, for high frequencies the vinyl gives a better sound than the CD, which exceeds it at low frequencies. Chris Tham believes that the high low frequency noise on the vinyl could be due to the original master copy (“Original Master Recording”) that may have been digitally processed prior to its use to record the CD in order to eliminate such noise.
For a song from the “Café Bleu” album of “The Style Council” he compared the original CD (1984) played, a digitally remastered copy of the CD (2000) also played, and the LP (1984) played. The dynamic range of the remastered CD is much greater than that of the original CD, which in turn is somewhat worse than that of the original LP. As for the spectrum of the signal, the LP reaches frequencies up to almost 40 kHz, when the original and remastered CDs are cut sharply around 20 kHz. The remastered CD has a “noise” band around 22’05 kHz, due to the dithering technique used to reduce the remastering noise. However, Chris Tham doubts that the frequencies above 25 kHz on the vinyl are part of the original recorded sound and believes that they could be artifacts due to the vinyl playback system. So in your next comparison, compare the LP with an audio DVD.
For the song that gives title to the album “What’s New” by Linda Ronstadt he compared the LP (1983) with a DVD-Audio (2002). The DVD-A is sampled at 192 kHz with 24 bits of resolution that Chris resampled at 96 kHz for comparison with the played LP. The dynamic range of the DVD-A is much greater than that of the LP, but what really attracts attention is the comparison of the spectrum. The DVD-A was recorded on the same master tape as the LP and has a noise band around 29 kHz (a horizontal stripe in the figure above, left), which does not exist on the vinyl and has its origin in the master tape. Comparing the spectrum of the vinyl with that of the DVD-A between 20 and 29 kHz, it is observed that the vinyl does not reproduce these frequencies well, but reproduces them, when a CD would not; Perhaps therein lies the great advantage of the LP over the CD, the reproduction of frequencies recorded on the master tape above 20 kHz. Even so, the DVD-A gives a much better sound than vinyl for these frequencies (audible only to some people with “good hearing”). Similar results are obtained for the comparison between LP and SACD (a variant of the DVD for audio only) and the audio on a video DVD (those interested can consult Chris’s article).
In summary, vinyl sounds better than CD because it has a relative dynamic range (perhaps due to “volume warfare”), although it has higher levels of distortion and noise at certain frequencies. Vinyl reproduces certain ultrasounds recorded on the master audio tape, although not with the quality with which high-frequency audio formats such as DVD-A or SACD reproduce it; But these ultrasounds are not audible to a normal person. Chris believes that the responsible for the “heat” that fans associate with vinyl as opposed to the “cold” of digital could be the distortion and relative dynamic range of vinyl; this last factor depends more on the sound engineer than on the format and on the tests performed by Chris with commercial recordings are greater on vinyl than on digital formats (including DVD-A and SACD), but their tests are concrete and do not correspond to A serious statistical study. My comment, since Chris leaves it as a question to the reader, is that what in the digital world can be considered a detriment, for vinyl fans could be a “benefit.”
On the other hand, as many of you have indicated, the biggest difference between a vinyl 30 years ago and a CD now is how the music was recorded in the studio, the so-called “volume war” (very explanatory YouTube video) . A record of today has to sound “good” in multiple media (from an mp3 while walking down the street, inside your car, in a crowded bar, in your living room, etc.), for what has tended to record music with very little relative dynamic range (very “normalized” sound); the problem is that at low volume it sounds fatal and at high volume quality is lost.
