CD vs. vinyl

wow...

only 2 writeups on this topic? well, here's my do-say pennies.

i'm going to ignore the mp3 vs. 'alternative' audio compression vs. other storage media for a bit and talk about CD's vs. Vinyl.
the compact disk format is an excellent storage media for music. the full range of the *audible* range of audio can be stored on it, and it has and excellent life expectancy as compared to other media, such as tape or vinyl.
the quality and quantity of audio that can be stored on vinyl comes nowhere near the cd format.

i personally don't think that's the point.

they are fundamentally different in the *use of the media*!
music or audio (i mean, really, what is music?) stored on vinyl instantly becomes a musical instrument with an incredibly expressive range. it can be speed up, slowed down, reversed, looped, rehashed and refried in to sounds that bear little resemblance to the original sound.
yes... you cd dj's out there are saying to your selves that you can do the same thing with cd's now that you can do with vinyl, but i beg to differ. vinyl let's you put your hand on it. caress it. be the 1 to 1 instrument of manipulation. cd playback will never have this kind of love. no matter how many DSP's and buffers you put on them.

i don't think it is a random occurrence that 2 'turntables' were recently components of the instrument that was used to recalculate the value of gravity :)

Ah this old chestnut. I must admit I'm not a zealot for either side in this debate, but I have some experience.

I have a general interest in hifi, that is, I try to keep up with the news, and like to think I can appreciate the good stuff. I myself own a Nakamichi Soundspace 8, which although made by Nakamichi, is a 'lifestyle' system. I use it mainly to listen to CDs, and record them onto minidisc (via an optical cable to my Sony MZ-R90 portable).

I personally think CDs sound great. I personally think Minidiscs sound great.

Maybe I don't have so called 'golden ears', or even decent hearing, but they sound just dandy to me. Conversely, my job has required me to examine and test many of the MP3 players on the market. I've listened to high bitrate MP3s on all sorts of portables, and through a decent sound system on the test PC. And I can hear the difference. It simply doesn't sound as good in my opinion.

As a contrast, my job has also required me to attend hifi trade shows, where many hundreds and thousands of pounds worth of hifi gear was mine for the fiddling.

I remember attending a demo in an Audio Freaks booth of some turntable or other, that looked like a prop from Wild Wild West (it was covered in bits of piping .. bizarre) and cost something like twenty grand.

This was hooked up via cables that looked like they belonged at the bottom of the ocean to a set of speakers so impressive I wept. Even though they were playing Dire Straits of all things, I had to admit I was blown away.

I heard many absurdly priced CD decks that day as well, including the Linn range, and the simple fact is that the vinyl sounded better.

But like I said before, I can't really hear the difference between a CD and a Minidisc in a blind test, so maybe I'm not the best authority on this.

I guess my point is that I won't buy an MP3 player because I can hear the difference, whereas I'm perfectly happy with my Nakamichi and Minidisc. In truth the Nakamichi is 'too good' for my ears, it's more than I need, but dammit I got my grades at A level, and that was my reward to myself.

If you are unhappy with the sterile sound of CDs, fine .. buy vinyl. There's enough of a specialist market in DJs and audiophiles to keep 'em coming for the forseeable future, so buy them, and quit whining .. I prefer SNES games to most PC games (it's the graphics .. ) but you don't hear me preaching ..

• The digital aspect of media stored on a CD does not degrade over time. Whether it be the first or millionth time a CD is played, the sound quality is the same. This cannot be said for records, which acquire a whole range of pops and hisses over time.
• CDs are FAR more portable than records. You can put them in notebooks, special cases, or simply in the original jewel cases they come with. This makes is easier to transport your collection to wherever you're going.
• You can listen to CDs in your car. You can't do this with vinyl (unless you are really crafty and don't care about scratches).
• You can listen to CDs in portable players. This is crucial for anyone who uses mass transportation or walks around a lot.
• You can skip tracks without having to aim. This is more a reason why CDs are better than tapes, but I'd be surprised if anyone claimed that.
• You can fast forward and rewind through an individual track. The uses for these features are obvious.
• There are commercial recorders available to make your own CDs. This means copies, mix tapes, and other creations are possible.
• CD Players require no maintenance, save a possible lens cleaning. Turntables require cartridges and needles regularly.
• CDs are shiny. They can be used to reflect sunlight into the eyes of an attacker.

In my opinion, these reasons far outweigh the reasons why vinyl is better than CDs.

The subjects of sampling frequency and dynamic range are important for any sampled time domain signal. In the CD audio format, these are set in stone and cannot be changed. I think these issues give some credence to the claims that vinyl is better than CDs.

According to the Nyquist Theorem, to capture a time domain signal in discrete form and reconstruct it from these samples without loss, the rate of sampling must be 2 times the highest frequency present in the time domain signal. CD audio is sampled at 44100 Hz. Therefore, a audio signal could have frequencies up to to 22050 Hz and be captured perfectly in sampled form. This signal can then be reconstructed mathematically using a series of weighted sinc functions. I won't go into the details, but I really mean perfectly (you audiophiles can argue this point all day long but you'll be wrong). The Nyquist Theorem is discussed in excessive detail in most signal processing textbooks.

There are two problems with a fixed sampling rate though, higher frequencies present in the audio signal and the electronic system used to recreate the signal from its samples. Sometimes there are frequencies higher than 22050 Hz in audio; the lucky among us may be able to hear them. When a signal like this is sampled, these frequencies which are higher than the Nyquist Frequency are aliased and wrap around in the frequency domain, smearing together with other, lower frequencies. This causes distortion. Secondly, even thought you can mathematically reproduce the signal with sinc functions and so on, the actual electronics (your CD player, using sample and holds, filters, etc) don't do it perfectly. Add in more distortion.

Dynamic range is another issue with CD Audio. It's 16 bit, so the samples themselves can only occupy a discrete value between 0 and 65535. The entire set of waveforms in an audio signal (parts in an orchestra, for example) has to be sampled and fit to a value in that range. Measurable sampling noise is a result of this operation. This is yet another source of nastiness in the reproduced audio. And think about it, is 2^16 values really enough to capture all the ranges in full bodied sound?

In my opinion, CD audio is very good but is probably limited for some types of music. When an audiophile says they can tell the difference between vinyl and a CD, they probably can. The super-CD format (22 bits I believe) is far better in terms of dynamic range and sampling. This may be able to fool even the best ear.

The problem with the arguments that most people wage in the holy war of Vinyl vs CD is that they fail to take into consideration every step in the recording and playing process. A typical vinyl zealot will formulate an argument by playing two versions of an album - one on CD and one on LP. What said audiophile has left out of his argument is the mastering and engineering of the album. Of course a rock album conceived at the pinnacle of analog recording technology will dwarf a recording made at the same time - the fetal stage of digital technology. However, not only has the recording technique and technology improved with the twenty or so years of digital sound, but the fact remains that more and more steps in the process are being done digitally. Why? I'm not a recording engineer, but I would gather that it's a combination of durability, ease of use, and cost.

The whole preference depends highly upon what kind of music you listen to. If i were into classic rock I would listen to vinyl almost exclusively. Not only did these bands record in an all analog environment during their heyday, but used record albums can be found at flea markets and record stores dirt cheap. However, if I listened to Top 10 type music on the radio, I'd buy CDs of my favorite artists (or corporate trash). Not only are these albums are produced in a digital heavy environment, if the vinyl isn't non-existent, it usually costs more than the CD, due to the lower demand.

As I listen to mainly electronic music, I am blessed by the best of both worlds. I typically buy albums on CD, as I'm sure the sound quality of something created with samplers and computers will sound better in the digital realm, and I find it somewhat of a pain to flip sides and search for tracks on vinyl. However, there are certain elusive singles that are only available as 12", thanks to this DJ heavy genre. And, call me a Luddite ape, but there is a certain satisfaction in dropping the needle and hearing the pop of it going into the groove.

From the perspective of a DJ, believe it or not, there are several reasons to choose CDs over vinyl.

The first reason is very important for a DJ playing on high-power sound systems. When you play records, you're taking a sharp needle, and dragging it across the physical representation of your music. Repeatedly. Ever hear of a little thing called erosion? This leads to a degredation in quality of sound. This does not occur with CDs.

The second reason is the flexibility that DJing with CDs can offer.* When you DJ using vinyl, unless you happen to own a vinyl press, you are limited to using only what production companies have felt the need to press to vinyl. With CDs, as long as you can find a CD quality (not that compressed shit) copy of the track, you can always burn and play it. (With the permission of the artist, of course.) It also makes life much easier if you produce your own music.

Third, it is more accurate to beatmatch with CDs than it is with vinyl.

I felt a disturbance in the force. As if thousands of vinyl DJs cried out in pain, and were suddenly silenced.

Yes, I know that this is easily the most controversial point I'm making in this dialogue, but it's a debatable point. When you drag and brush a record on a vinyl turntable, the rate of change is subtly affected by several variables, including the size and drag of the hole in the middle of the record, the moisture and heat level of the slipmat, and many other variables, mostly having to do with the number of points of friction present when using vinyl. The same level of brushing or dragging can produce different results in the pitch change, a disadvantage that doesn't exist using CDs. This is a subtle advantage, but to a perfectionist like myself, it is a notable one.

Another reason that CDs *can* be better than vinyl is the wealth of options that are available with CD equipment that would be impossible to have on vinyl. With the advent of the Digital Vinyl series by Pioneer, DJs on this equipment can scratch or perform backspins with ease. There are CD players that come with built in samplers and looping functions, allowing the DJ many options in creatively cutting up and remixing music. The looping function in particular is completely infeasible to have on vinyl equipment. With the release of the CDJ-1000 CD player by Pioneer, suddenly the technological goodies available for CD DJing shot through the roof. This bad boy even comes with a memory card that you can use to preprogram cue points, loop points, and even use as a sampler. I defy *ANYONE* to to show me a vinyl turntable that can do this.

The best reason to choose to DJ CDs over vinyl, though, is really simple. Like the softlock says below: personal preference. Some people are very, very attached to the tactile aspect of using vinyl to DJ. For some people, this same thing would be a liability. If you prefer to deal with things in a tactile manner, vinyl would probably be best for you. However, if you prefer to deal with things as non-concrete, abstract concepts, CDs would probably be more your speed.

Lastly, I never, ever, once will ever have to pay to replace the cartridge on my equipment. Bwahaha.

I'm not saying that CDJ equipment is intrinsically better than vinyl. Far from it. Vinyl DJing is an important part of DJ culture, and I would never, ever want it to go away. For certain applications, vinyl is far superior to CDs. But for those with an open mind about what equipment will be best for them, there are just as many reasons to choose to DJ using CDs than with vinyl.

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*Update: mkb has informed me of a product called Final Scratch that can be used to play Mp3s from computers using vinyl turntables. Odd, I know, but it is an extremely clever product. A cursory glance at Google, however, reveals a price tag of $500 for this setup, making it only viable for those people who are willing to spend an extra half a grand to either avoid the social stigma of DJing using CDs, or who are already set up and used to using vinyl. I, personally, would rather just spin CDs than spend a couple thousand extra dollars on equipment and a laptop so that I can rip and spin music on vinyl that I'll be buying on CD anyway, b/c it simply isn't available on vinyl, or for legal MP3 download. I'm just not that interested in following the status quo.

The debate of CD vs. vinyl is a popular religious issue amongst music fans, audiophiles, DJs and techies. The arguments are usually peppered with scientific factoids ranging from the pedantically correct to the hilariously mistaken. Here I intend to explore the technical issues in a balanced manner. Reasoned scientific feedback, debate and corrections are most welcome.

I shall try to avoid the quagmire of subjective aesthetic judgement; having never owned any vinyl records I couldn't say which format sounds "better".

The Frequency Domain

Frequency is pitch - the difference between a low, deep sound and a high piercing sound. As we hear sounds as a sum of frequencies, most of the important information is in this domain, and accurate reproduction is correspondingly important.

The sample rate of a CD is 44,100 samples per second. According to the Nyquist theorem this is sufficient to capture all the information in a signal that contains no frequencies above 22,050 Hz.¹ This bandwidth is more than enough. The human ear is most sensitive at around 3,000 - 4,000 Hz. (The fundamental tones of a piano range roughly 25 Hz to 4,200 Hz)  The upper frequency limit for human hearing is roughly 20,000 Hz, while for a middle aged male this figure may be nearer 15,000 Hz. At both extremes of the audible frequency range the perceived loudness relative to the signal power is less than that for moderate frequencies.

The reason for this extra sampling overhead is actually to make the CD player's job a little easier. When recreating an analogue signal from digital data it is necessary to filter artefacts generated above the Nyquist frequency (in this case 22,050 Hz). Analogue filters with sharp cut-off slopes are expensive, so a 2,050 Hz gap to ramp down is quite helpful. Still, a poorly designed filter might unduly attenuate the audible high end or have a "ringing" frequency response across the full range.

Sound behaves linearly, which means that frequencies above 20,000 Hz cannot somehow affect, alter or "shape" the lower, audible sounds. Nevertheless, audiophiles often believe that these high frequencies actually do make a difference. The best scientific support I have seen for this view is a paper² which suggests that brain activity may be somehow affected by the presence of hypersonic sounds.

Frequency domain issues with vinyl have an entirely different nature. First off, vinyl records are not recorded with a constant frequency response. To properly reproduce low frequencies would require larger grooves, so records are pressed with the low frequencies reduced. In addition, as a strategy to drown out noise, higher frequencies are boosted on the recording. A RIAA equalisation amplifier mostly corrects the frequency response on playback. Problems introduced by cheap turntables include "wow and flutter", which refers to frequency shifts caused by variation of playback speed and "rumble", low frequency noise from the motor.

Dynamic Range

The dynamic range is the resolution of the recording - the ratio of the loudest possible sound to the softest, expressed in the logarithmic decibel (dB) scale.

For CDs, each sample has a 16-bit range (65536 values). This might not seem to be a great deal but it actually translates to roughly 96 dB dynamic range. I would argue that this should be sufficient for any music, when we consider the range of human hearing.

By definition, decibel levels are always comparative - the difference between the loudness of two sounds. When you see an absolute figure quoted, ("A lawn mower measures 90 dB") this is in relation to a defined zero point - 0 dB is defined as the softest sound audible to a person with perfect hearing. This means that if you set the volume of your CD player such that you can hear all the sound it contains, the loudest point on the track will measure at least 96 dB on the absolute scale. Listening at a higher volume than this for too long will reduce the need for a large dynamic range.³

The biggest general misconception about analogue technologies is that they have infinite resolution, which is never true. (In this example, a PVC molecule is small, but not infinitesimal). In practice, the dynamic range of vinyl records is affected by the age and quality of the recording, and the density of the tracks. The best-case seems to be around 60 dB. The dynamic range will be adversely affected at low frequencies because of the equalisation issue detailed above.

Errors and Noise

CDs are recorded with interleaved redundant information built in. This allows the decoding machinery to correct or interpolate bad data caused by damage to the CD surface. However, should the damage be too great, the CD will simply skip.

Any wear to the surface of a vinyl record will cause a gradual deterioration in the quality of the recorded signal. This manifests as hiss and reduces the effective dynamic range. Scratches and other damage can result in pops and clicks that momentarily drown out the recorded sound.

Conclusions

CDs technology is mostly an improvement on vinyl technology. Stop worrying and just enjoy the music.⁴

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1. Frequencies above the Nyquist point will cause interference if not removed before sampling. This is one motivation for sampling at higher rates in the studio.
   
2. Oohashi, Tsutomu, Emi Nishina, Manabu Honda, Yoshiharu Yonekura, Yoshitaka Fuwamoto, Norie Kawai, Tadao Maekawa, Satoshi Nakamura, Hidenao Fukuyama, and Hiroshi Shibasaki. Inaudible high-frequency sounds affect brain activity: hypersonic effect. J Neurophysiol 83: 3548–3558, 2000.Also available online at: http://jn.physiology.org/cgi/reprint/83/6/3548.pdf
3. In UK workplaces hearing protection is mandatory for sound levels above 90dB.
   
4. I've never listened to so much music as I did when I was 17, using a cheap cassette player. There are factors more important than bidirectional copper cable.