The CD is 30 years old today • Hacker News Board

Re: The CD is 30 years old today

#31

Post by macchina » Mon, Oct 01, 2012, 10:46 PM UTC

dsk2012 wrote: post #13

erickhill wrote: post #9

When is the music industry going to actively promote (and select) a high definition music format? Like, Blu-Ray for audio-only?

Never. First, CD audio quality is good enough. Second, the market is in transition (already transitioned?) to a pure digital format, distributed either via flat files (e.g. mp3s), or via SaaS streaming services. Similarly, Blu-ray is probably the last physical format for movies.

Well there is still an option for so called high definition digital downloads. Although MP3 audio quality is good enough, I wouldn't rule out the possibility of companies marketing "high frequency" "lossless" recordings at a premium price.

Re: The CD is 30 years old today

#32

Post by squarecat » Mon, Oct 01, 2012, 10:52 PM UTC

runjake wrote: post #16

dsk2012 wrote: post #13

Earlier quoted context omitted.

Never. First, CD audio quality is good enough. Second, the market is in transition (already transitioned?) to a pure digital format, distributed either via flat files (e.g. mp3s), or via SaaS streaming services. Similarly, Blu-ray is probably the last physical format for movies.

NPR mentioned this morning that digital music download sales far exceed physical media music sales already. This might explain there being virtually no record stores around anymore.

Heard that story this morning: http://www.npr.org/blogs/therecord/2012/10/01/162062347/the-...

Made me consider stockpiling a supply of CD players to gouge future hipsters with...

Re: The CD is 30 years old today

#33

Post by squarecat » Mon, Oct 01, 2012, 10:54 PM UTC

kree10 wrote: post #24

ChuckMcM wrote: post #7

Earlier quoted context omitted.

Long boxes so that when you put them into the place where the store used to display LP albums the title was still at a comfortable reading height.

I remember reading that longboxes were a way to prop up the LP jacket manufacturers, since the materials and process were similar, but... "citation needed".

https://en.wikipedia.org/wiki/Longbox

Re: The CD is 30 years old today

#34

Post by rcxb » Mon, Oct 01, 2012, 11:17 PM UTC

msh wrote: post #12

I am sad that the minidisc lost out to the cd :(

The minidisc was a great technology at the time, but it's probably for the best that it didn't catch on. Minidiscs used lossy encoding, so ripping your MDs to MP3s would sound pretty bad. And these days, hard drives or flash storage is far superior. What would have been nice is if DVDs and Blu-Ray adopted the MiniDisc form factor... Scratch-free movies from Netflix, in a tiny package that's far quicker and easier to handle.

Re: The CD is 30 years old today

#35

Post by stan_rogers » Mon, Oct 01, 2012, 11:19 PM UTC

thirdhaf wrote: post #29

stan_rogers wrote: post #17

Earlier quoted context omitted.

There were three and a lot of noise around them at the time: HDCD; DVD-A; and SACD. A very small handful of audiophiles cared, nobody else was paying enough attention to hear the difference. (For the people who are going to bring up Nyquist, that is true of the frequency domain, but not of the time domain, and differences in timing affect spatial resolution more audibly than they do timbre.) Really, it only matters t…

Assuming 44.1kHz sampling rate the smallest path length difference between the ears is approximately 6.8mm. This corresponds to 2.3 degrees (with sounds source at infinity). Humans can place sounds with about 3 degrees of resolution so unless you have some citations I am seriously skeptical about the claim that higher sampling frequencies gives you anything whatsoever.

44.1KHz is not the output frequency; it's the sampling frequency from which an unambiguous 20KHz signal (of sufficient amplitude) can be reconstructed. So your calculation needs to take into account that the maximum peak resolution is 20Khz (and that 16 bits may not have sufficient amplitude sampling resolution to accurately interpolate the waveform peaks even if their frequency -- their spacing rather than their position in time -- can be reconstructed unambiguously).

Re: The CD is 30 years old today

#36

Post by razzmataz » Mon, Oct 01, 2012, 11:56 PM UTC

runjake wrote: post #16

dsk2012 wrote: post #13

Earlier quoted context omitted.

Never. First, CD audio quality is good enough. Second, the market is in transition (already transitioned?) to a pure digital format, distributed either via flat files (e.g. mp3s), or via SaaS streaming services. Similarly, Blu-ray is probably the last physical format for movies.

NPR mentioned this morning that digital music download sales far exceed physical media music sales already. This might explain there being virtually no record stores around anymore.

It's not 'far exceed' - last year was the first that digital sales exceeded CD sales, by something less than a percentage point. Still, it's nothing to sneeze at.

Re: The CD is 30 years old today

#37

Post by acchow » Tue, Oct 02, 2012, 12:05 AM UTC

The compact disc has always felt to me to be a decade ahead of its time. In 30 years of removable storage media, we've only managed to go from CD's 700MB to BDXL's 128GB. That's only 182 times the capacity, or 2^7.5

Re: The CD is 30 years old today

#38

Post by thirdhaf » Tue, Oct 02, 2012, 12:41 AM UTC

stan_rogers wrote: post #35

thirdhaf wrote: post #29

Earlier quoted context omitted.

Assuming 44.1kHz sampling rate the smallest path length difference between the ears is approximately 6.8mm. This corresponds to 2.3 degrees (with sounds source at infinity). Humans can place sounds with about 3 degrees of resolution so unless you have some citations I am seriously skeptical about the claim that higher sampling frequencies gives you anything whatsoever.

44.1KHz is not the output frequency; it's the sampling frequency from which an unambiguous 20KHz signal (of sufficient amplitude) can be reconstructed. So your calculation needs to take into account that the maximum peak resolution is 20Khz (and that 16 bits may not have sufficient amplitude sampling resolution to accurately interpolate the waveform peaks even if their frequency -- their spacing rather than their pos…

Completely agreed about 44.1kHz being a sampling rate. To make the rest of the numbers nicer I'm going to pretend we're talking about 40kHz sampling for the rest of this comment. It's clear that you can't distinguish between a 0-degree phase shifted 20kHz signal and a 0-degree phase shifted 60.0kHz signal (I thought we weren't going to talk about Nyquist here). However by the same token you CAN represent a 90-degree phase shifted 20kHz just fine. By way of example consider the bit stream (I'm also pretending 1-bit sampling for now) [0 1 0 1 0 1] which in this format represents a 20kHz signal. It's pretty obvious that we can represent the 90-degree phase shifted signal as [1 0 1 0 1 0] and there's nothing in the input stage that stops the original source from creating this particular type of signal. In fact we can unambiguously represent ANY phase shift in the same fashion, but as you point out then we start arguing about whether your sample has enough precision to unambiguously represent the input. With a 90-degree shift (corresponding to a ~23usec delay) we have none of the precision problems you allude to.

Re: The CD is 30 years old today

#39

Post by waterlesscloud » Tue, Oct 02, 2012, 1:02 AM UTC

gbeeson wrote: post #4

This article also reminds me of where I used to pick up CD's back when they first came out - Tower Records in Mountain View, CA. CD's - still around; Tower Records - not so much. Interesting how it all worked out.

So I dropped out of college for a few years, and during that period I worked at the Tower Records in Atlanta for about 2 years. This was First Gulf War time, so it must have been 90-91. Fun job, still friends with more people from that job than any other I've had. It was no one's first record store job, so everyone there was pretty knowledgeable about at least a couple musical genres. Company was not exactly a model of good management techniques, but whatever, as a sales clerk it was great fun.

Anyway, I remember one night stuck on the cash register and bored, so I did some literal back of the envelope calculations. I took the CD storage capacity and the trend in increasing data rates for modems and figured out you'd be able to download albums in a practical amount of time in about the year 2000. I then told all my co-workers to not make a career of the record store business because we were all doomed by digital downloads in about 10 years.

Funny how much I got wrong but still got the end result right.

Re: The CD is 30 years old today

#40

Post by sjwright » Tue, Oct 02, 2012, 6:51 AM UTC

dollarpizza wrote: post #20

joeyh wrote: post #5

http://article.olduse.net/7038@philabs.UUCP That's the second ever mention of the CD made on Usenet, back in July 1982. "It has no grooves, the digitally encoded recording lies beneath the disc surface, invulnerable to dirt and damage."

invulnerable to dirt and damage Yeah. Who'd'a thought they'd end up being even more perishable, & way more disposable than vinyl....

Compared to vinyl, the CD would have seemed invulnerable to dirt and damage. Even more perishable? What bunkum. Every time you play a vinyl record, you're causing a very small amount of irreparable damage. Whereas I can still retrieve a bit-perfect copy of my 20+ year old CDs, even if the underside is severely scratched.

That said, how can you resist the psychological conundrum of knowing that every time you play a record, you are forever damaging it a little bit... That you're forced to destroy what you love. That like life itself, every minute it's turning brings death a step closer. That one day your old records might match your own ears' diminished high frequency response.

There's something poetic there.