Digital Equivalent of LP

[Tyler2000]

It is my understanding that LPs (records) work by running a 'sensor' over a series of notches and grooves to replicate a sound recording.

CDs work by recording samples of sound at set intervals, and playing those samples back into a version of the sound that doesn't include all the 'frequencies' of the original sound. Standard CDs can't include all 'frequencies' of sound because of their data capacity.

So my questions is that if an LP can record a high level of audio quality using notches and grooves, how much capacity would a digital media need to hold the same amount of information?

Do DVD-Audios sound as good as LP?

[trhouse]

That is incorrect. Sampling at greater than twice the highest audio frequency allows recreating the original audio perfectly.

Here is a link to the theorem,

http://en.wikipedia.org/wiki/Nyquist-Shannon_sampling_theorem

[davideck]

If you Google on audio sampling theory, etc. lots of good stuff will turn up.
Here's a start;

http://www.teamcombooks.com/mp3handbook/11.htm

http://www.lavryengineering.com/documents/Sampling_Theory.pdf

[hech54]

Do DVD-Audios sound as good as LP?

[Cornucopia]

It is my understanding that LPs (records) work by running a 'sensor' over a series of notches and grooves to replicate a sound recording.

CDs work by recording samples of sound at set intervals, and playing those samples back into a version of the sound that doesn't include all the 'frequencies' of the original sound. Standard CDs can't include all 'frequencies' of sound because of their data capacity.

So my questions is that if an LP can record a high level of audio quality using notches and grooves, how much capacity would a digital media need to hold the same amount of information?

Do DVD-Audios sound as good as LP?

By definition, Analog recording has "infinite" frequency response if you're talking absolutes. And in that vein, NO "sampling" digital format (be it audio, video, photo, etc) can hold "infinite" digital code.
Realistically, however, Analog LP response slopes downward after 15-22kHz (if using a standard needle/cartridge), or after 30-45kHz (if using a Shibata needle/cartridge). Then there are some questionable variables...
How far downward is good enough?
Good enough for whom? For what purpose?

If it's a choice between getting 80% and 90% of the signal, obviously 80% may not be acceptable, but 90% usually is.
My estimate is CD's get you ~93% of the LP signal and DVD-Audio/SACD's get you 99%. You still won't get 100%, but the rest is so infinitessimally small that it can be ignored by just about everybody except Sampling Theorem scientists and diehard nostalgic analog luddites. (Sorry, not trying to bait/flame here. That's just what I believe).

So, in simpler terms:
(assuming things were digitized/recorded/produced/mixed/mastered well to begin with, and only LPCM/MLP/DSD is used)
CD's can sound great, but there are times when it is lacking compared to the best quality analog.
DVD-Audio/SACD's can sound amazing, and have yet to be found lacking.
In many ways they sound better: Dynamic Range and Dynamic Linearity, Frequency Response Flatness, LESS SELF-NOISE AND DISTORTION, Less susceptability to external influences (noise, hum, bumps), LESS Wow and Flutter, somewhat more durable, MULTICHANNEL capability...

BTW, LP's don't have "notches". They have a continuous ribbon of hills and valleys, and the pressure on the needle/cartridge from the slope (rise/fall) is a direct analogy to the original signal. If you were to take a microscopic picture of a rotary cross-section showing the movement of the "ribbon" in time, it would look just like the electrical audio waveform itself.

Scott

[Tyler2000]

trhouse, what is incorrect? Are you saying CDs do sound as good as LP? I thought the general opinion was that they didn't sound quite as good?

I didn't search google for this subject because I'm not an engineer and I don't have much knowledge of audio/music in general.

It was my understanding that CDs don't sound as good as LP because they can't hold as much data and I was asking how much capacity would be required for a digital equivalent of LP?

If the data capacity of a CD is not the only limitation of the format, please try to explain it to me, but keep in mind I'm not an engineer.

hech54, does your smiley suggest that the answer to the question is 'no' ?

[mzemina]

Look at [urlhttp://www.microscopy-uk.org.uk/dww/home/novhome.htm]this website[/url] for some pictures of LP record. Not as close as I'd like to show but hopefull you will get the idea.

Mike

[Tyler2000]

Thanks Cornucopia. That answered my question fairly well.

[hech54]

I remember when CD's first came out. There was some nutball on Good Morning America trying to explain how and why LP's were better than CD's....until it came time for the "pops and clicks" questions....and then came the "recordings done completely digital"....then he had absolutely no answers.

[greymalkin]

the technology used in records still have applicable uses today.

take..the see n' say..for instance. Nothing more than a plastic record/needle/cone.

Analog has qualities that digital will never be able to be "better" than in some aspects (no matter how many samples per second you have it's still samples), but the drawbacks of analog (mechanical noise) do it in.

[Dr_Layne]

The problem with analog vs digital argument is when you start comparing dollars for dollars. A $50 turntable will not sound as good as a $50 cd player. In order to get an amazing sounding analog turntable rig will require thousands of dollars to outdo a cd player. I'm not one to lean one way or the other, I like analog and dgital for various reasons. Digital will never be able to sample sound accurately, no matter how many bits, or khtz, or samples per second are used. But, the results are normally "good enough".

[piano632]

Here is a spectral analysis of vinyl vs. digital. You may be surprised at how well LP's will hold up against even the high-res digital formats like SACD and DVD-A.

http://users.bigpond.net.au/christie/comparo/part4.html

I'll say one thing, CD's don't have the ambience or sense of presence that vinyl has. And the audiophile community is till pressing vinyl by the boatload.

[Cornucopia]

I'm somewhat familiar with that site/link. The construction of the test is slightly flawed, but that's minor.

What has been shown on sites and in Audio Engineering textbooks is that the LP has "EQ coloration", "non-linear/slightly exaggerated dynamics", "enhanced difference channel modulation" (L-R), possible 2nd order harmonic distortions, and surface noise.
All of these things are scientifically detrimental to the audio signal, but are many times considered an "improvement" in human listening tests.
The EQ colorations and 2nd order harmonics make the sound seem "warm" or "fat" or "bright". The non-linear dynamics make the sound seem "lively". The enhanced L-R increases the Stereo Width and Ambience. The surface noise (hiss) can act like additional harmonics and "brighten" the sound. It may also be similar to dither. But these "improvements" aren't the same for all listeners. That's probably why it's better to stick with "flat" or "even" scientific benchmarks.

What I've heard most engineers haven't like about CD isn't the sample rate, but the bit resolution. 24 bits is MUCH better than 16, even if you don't use all of them (the bits). Reverb and Nature sounds are particularly enhanced. SACD does and DVD-Audio can make use of 24 or 20 bit audio. Even DVD-Video includes it in the spec, although it's rarely used.

Scott