Okay guys, I will concede that the issue of Vinyl vs.CD is complicated by the 'loudness wars' and resultant compression of dynamics that has been employed and imposed by recording engineers on the vast majority of CDs produced since about the mid 1980's.
If this very significant compromise of CD performance caused by the recording engineers' misguided compression practices were not utilized, however, an accurate summary of comparing vinyl to CD would be the following:
Dynamic range. The difference between the loudest and softest sounds an LP can play is about 70 decibels (dB). CDs can handle over 90 dB. In practical terms, this means that CDs have more than 10 times the dynamic range of LPs. 24-bit digital audio affords 144 db dynamic range.
Surface noise. Dust particles in the grooves of an LP cause crackles and ticks that are present and audible no matter how well you clean the record. CDs are not affected by surface noise, because they use light beams to read the musical data, which ignore any foreign substance on the disc. Besides that, vinyl records have an underlying hiss generated by the needle moving over the surface. CD and 24-bit audio have no surface noise.
Mechanical noise. Every turntable, even the most expensive, generates a low-frequency rumble that is transmitted by the stylus into the amplifier and speakers. The system has to work much harder to handle all that low-frequency energy, and that can cause distortion in other parts of the audio spectrum. Many audio systems include a rumble filter that can reduce this, but that filter also removes the lower-frequency sounds on the record, like the bottom octave of a piano, or the low tones that give a bass drum so much of its power. CDs and 24-bit audio have zero mechanical noise.
Speed variation. Listen to a recording of a solo piano on an LP, and then on a CD. I’ll bet you can hear the difference immediately. Vinyl depends on a mechanically driven system, and any such system will introduce minute changes in the speed and pitch of playback. A vinyl record that is even slightly warped, or has a hole that is not perfectly centered, will have “wow”—slow variations in pitch. Tiny imperfections in the belts or wheels of the turntable will cause more rapid pitch changes, known as “flutter.” CD players, because they use super-accurate digital buffers, are immune to this. as are 24-bit audio players/computers.
Channel separation. On a CD, the separation between the left and right channels used in recording is over 90 dB. 24-bit audio is greater than 95 dB across the entire audio range. On LPs, it’s 30 dB at best. That means engineers have a much narrower range to work with when they’re mixing and mastering the audio, and the result, for the listener, is that the stereo “image” is highly constricted. It’s worse at lower frequencies; a loud bass signal in one channel of a record can push the needle out of the groove, so engineers have to make sure bass frequencies are always in the center.
Continuous vs. “chopped up.” Some people believe that because digital audio “chops up” the signal into discrete numbers, it cannot carry all of the information that an analog signal does. But before the digital signal reaches our ears, it is reconstituted into a continuous analog wave. The process does filter out sounds above 20 kHz, which is the highest frequency the most acute human ears can hear. However, no phono cartridge, amplifier or speakers can reproduce those frequencies anyway. So really, nothing is taken out that affects the sound.
Longevity. Friction causes heat, which softens plastic and makes it easy to deform. This means that every time you play a record, the smallest peaks and dips—the high frequencies—soften and can literally get shaved off. The more you play it, the worse it gets. Also, whenever the needle encounters a dust particle, it gouges a hole in the soft surface, so that pop or crackle becomes permanent. By contrast, CDs and 24-bit audio files will sound the same essentially forever, unless you leave CDs on your car dashboard on a sunny day or bring a powerful magnet near a hard drive.. And you can always make as many perfect copies of them as you like.
CDs and 24-bit audio reflect exactly what the artists recorded in the studio. Vinyl distorts it. Some listeners honestly feel that the defects vinyl introduces somehow make it more attractive or “warmer.” But from any objective standpoint, there’s no justification in calling the sound of vinyl records “better.”
Despite all of the above, however, I can still understand why many prefer listening to well cleaned vinyl lps on a good TT based system to the compromised sound of many redbook CDs.
But digital is not limited to just the mediocre quality of MP3, AAC and redbook CD or even the higher quality SACDs.
I've discovered the true potential of digital is realized with music recorded directly to digital and played back as 24 bit/96khz hi-resolution or above. The sound quality is superior to any other format I've heard.; dynamic range that actually match the wide dynamics of real live music, very accurate tonal accuracy from top to bottom and a combination of high detail levels along with virtually no background noise that enables a very stable and real sounding sound stage illusion.
In my experience, a minimum of 24 bit /96 khz playback of digital files that have been recorded direct to digital is required to achieve the exceptionally high quality sound I described above in my system. The more common transfers of the original analog master (typically recorded on hi-speed reel-to-reel tape) to hi-res digital format also sound very good to me. After all, it is an exact copy of the analog master.
But I'm still able to discern the direct to digital recordings by their wider dynamic levels, dead quiet background levels (especially between songs but less so during songs) ,higher detail levels and a more extended treble.
My main point is that digital has moved well beyond CD quality to high resolution digital. I just hope recording direct to hi-res digital becomes the norm soon because we'll all benefit from that and all who wish can still enjoy their vinyl.
Tim