The Digital Myth

Apologies if this has been on here before, but I hadn't seen it:

http://www.johnvestman.com/digital_myth.htm

Remember kids, make sure both hard disks in your empeg are the same make, or you may experience "more sterile and harsh sounding" audio on one of the two.

ROTFL.

Peter

Okay, that IS a joke site isn't it?!?

"My favorite: Maxell 700 MB silver top for more detailed highs, Maxell Music gold for a fatter, more solid mid-to-bottom. Fuji 80 Minute Audio cds are my next favorite, Sony and Memorex 700 MB are close, the BASF is in there... experiment and see what you prefer!"

Do you think he has a favoured CDR drive as well? For rounder, fuller pits in the dye layer

- Trevor

I don't think I've read such utter crap in all my life. The author of this really doesn't understand what Digital is does he. What a prat.

Okay, that IS a joke site isn't it?!?

Dunno. It was linked from today's NTK, and their "When Audiophiles Attack" link last week definitely was a spoof (sulphur hexafluoride-filled balloons to increase speaker air mass). But I'm not so sure about this one.

Peter

He seems to be confusing DAE with discrete files on a filesystem. It's absolutely true that the quality of audio can vary considerably between CDR brands _if_ you are writing an audio CD. This is as much the fault of the CD player as the media, and also applies to audio DAT.

Of course if you have a filesystem the data is going to be exactly the same or cause an error, nothing in between!

Rob

Some of the stuff he talks about can be explained by DAC jitter issues, as described here. But I think he's got an incorrect understand of How Things Work.

I've never noticed any sound difference like "fullness" between CDR brands apart from the fact that some don't play very well on certain CD players. *shrug* I've got terrible hearing anyway so it all sounds the same to me

- Trevor

I personally like ``I know of a top music editor for film in LA who only uses one brand of hard drive because he can hear the difference between brands.'' Despite the fact that it is easily empirically provable that the data would be exactly the same no matter the brand of hard drive.

Then again, he might be referencing the fact that some drives have better throughput than other drives, which could conceivably make a difference if he's recording. This pretty much sums up this guy's article, IMHO. He might have some valid arguments, but he apparently knows so little about his subject that he's unable to articulate his points, and it just makes him sound like an idiot.

Guys, DUH!!! It's on the internet, so it's true. Why are you questioning it?!

Nah. I've yet to have it forwarded to me as an attachment!
And of course, it's not been on TV yet so...

- Trevor

It has to be real if it's on the net.

If only I can find that yeti....
http://www.phobe.com/yeti/use.html

Hehehehe, where do you guys FIND this schitt. Yeti@home had me rolling.

BTW, look at this... http://www.kenner.la.us/mason/bomb.jpg

Ouch. Time to change da pants.

I hate to sound like I'm agreeing with Mr. Vestman, because he really has got the wrong end of the pineapple (Computers crash, computers are based on ones and zeros, therefore ones and zeros are not perfect? A fallacy, just to start). But there is an important consideration, especially in copying or mastering CDs to CD-R media. It's not perfect.

This comes back to something that's been talked about here before - the fact that if you take 74 minutes of 44.1KHz 16-bit stereo music, it actually works out to fit in 783,126,000 bytes, or ~746MB (1KB=1024B). So why does the same size CD-R advertise '650MB'? Where is the extra ~100MB? Why have you lost 15% of your recording space?

The answer comes down to the way information on CDs. It's not just linear like a hard disk, because there are all sorts of issues with light phases, interference and timing when you read data optically. You can't simply encode a 1 bit as a rise and a 0 bit as a pit (for example). You have to make sure that if you're encoding a certain number of bits in a row that are the same, that there's some way of telling which bit you're actually currently reading.

This combines with the fact that even the tiniest bit of grease or dust totally and utterly changes the information coming from the disk. So the way the CD Audio format is written is that the data is expanded[1] into a form that errors can be detected and corrected completely inaudibly. That is: the media can detect and correct a certain amount of errors and this is done automatically.

However, no system is perfect and there is always a point at which you can't detect a large enough error (as Hamming showed). There are ways to reduce the effect of these errors, so most of the time you won't hear a thing. But a badly made copy of a CD, or even an original CD that has a lot of surface wear, will start physically sounding different. Given that not all CD-R dye media is the same, that it is more sensitive to the effects of time and wear (e.g. sunlight) than a metal-pressed CD-ROM, and that the faster you write the less impression on the dye you make(so to speak), there will be a point at which a copy can be differentiated from the original by ear alone.

But what of DAE, you say? If we've extracted the data from the CD digitally we don't have transcription problems, I hear you cry. And, indeed, this is partly the case. You are more likely to get the same bits off a CD as were on the original master tapes if you use DAE. And, likewise, ExactAudioCopy is better than AudioGrabber which is better than Dodgy Bob's Hi-speed Ripper, because in general the more times you read the source the more likely you are to work out which bits are correct in which copies (but you have to read at least three times in order to know positively. Proof of this is left as an exercise for the reader).

But still you have the problem of writing that information onto a CD-R. The page on Jitter that Tony mentions has a case in point - on really good quality equipment and when you know what you're listening for you can hear the difference between a write at 1x speed, 2x speed and 4x speed. And it's my prediction that all those people who think that 40x speed writers are excellent for writing copies of CDs and software will be laughing on the other side of their faces in two years time as the dye gradually loses its markings and the CDs become more unreadable. Already I'm having problems reading CDs that I wrote at 4x speed over five years ago...

So while Vestman's article is more pseudoscience, mumbo-jumbo and self-justification than anything, there is truth underneath the layer of grime...


[1] The simplest expansion encoding is 0 => 01, 1 => 10. This not only ensures that you never get more than two of the same bit in a row, but also allows one bit of error correction. If you receive the sequence 0101111010, then you can detect that the '11' pair is wrong. Depending on the way the media works you can make an educated guess as to whether this should actually represent a 1 or a 0. There are, of course, much more intelligent ways of encoding than this simple example.

The problem with this argument is that it's easily possible to write data to a CD-R with no errors whatsoever. I won't get into the problems associated with aging CD-Rs, and I don't know enough about the differences between how data is written and read and how audio data is. But if CD-Rs didn't record the exact bits of data that you requested that they record, then they'd be useless, and I think enough of us have written real data to CD-Rs to know that that sort of thing just doesn't seem to happen, at least not on a regular basis.

Actually, now that I say that, I realize that I do know one significant difference. The ISO-9660 filesystem contains a good bit of error correction. So if you need to write immutable data, use a filesystem, not just audio tracks. And, assuming that that's the purpose of using CD-Rs to master your data, audio or not, one would wonder why you wouldn't do it that way anyway. We, as a community, have been developing ways to extract audio data off of CDs better and better for years now. But we know how to extract data from a filesystem in an optimal manner, so why not just record it that way anyway? Of course, you'll need to eventually record it down to an audio master if you plan on pressing CDs (I assume), but premature opimization has been a problem since the beginning of computers. I guess we're getting to the point where even laypeople need to know about that.

I've noticed distinct audio differences (more subtle than skipping or failure to play) on some CDR's compared with others. In general it's the cheapo spindles full that give problems, but not always.

I assume the problem is caused by the disc being less than perfectly readable by a consumer CD mechanism, and so the error correction/over sample/other widgets are working over time. I doubt the same problem exists if you use a CD ROM drive to play the disc (or more modern CD player, perhaps).

Rob

Yes, there are some weird notions in Audio-land. As another example, perhaps more absurd have a look at:

http://www.belt.demon.co.uk/product/product.html

This guy, Peter Belt, is completely serious, has been around since late 80's (or at least that's when I first heard of him.

Nothing to do with digital, just thought I'd take off-topic further off-topic

Cas.

I think he is very serious, he is selling a small crocodile clip for £500 on this page:

http://www.belt.demon.co.uk/product/quantum/quantum.html

OMG! He says you have to mark the edges of your CD with a violet pen, then "tap" each marking to make it work? HAHA! I especially love the drawing of the top of the pen where it's like "tap with this part". HA!

Then he says to mark the back of a VHS cassette? Like on the plastic part of the box? What the hell does he think that could possibly do?

PLEASE tell me this isn't real....

"Chunky Violet Pen"

You missed the best bit where he has you sticking foil over the words "Compact Disk" on the surface of the CD or the 33 1/3 text on a record (he has been at it a while)...

I'm afraid he is very real, has has had this stuff featured in hifi magazines in the past.

So sad...

How many people do you think are actually taken in by this pseudoscience clap trap? I can't honestly believe he's had any more than zero takers. He's just gotta be joking... Hasn't he? After all nobody in their right mind would fall for it... Would they?

I'm afraid they would. For instance, look at this. I know the guy who wrote the software for the latest version, running on a PC, and the company has sold dozens at a couple of grand apiece. Some to fairly wealthy individuals, as well. I've heard that a particular music type person from iceland has bought one, for instance.

When you come down to it, people are idiots.

pca

How can anything calle Electro-Crystal Therapy be considered serious by anyone??? Personally, if it has "Crystal" as the prominent word, I equate it with Miss Cleo.

That chode doesn't even know how to set the date on his camcorder.

That chode doesn't even know how to set the date on his camcorder.

More likely, he's a chode who lives in a country that arranges its date format in a different field order than in your country.

who writes the year with a single character, like 2 instead of 02 or 2002?

who writes the year with a single character, like 2 instead of 02 or 2002?

People who wrote camera firmware before the turn of the century and didn't think to check whether the year looked good without a padded zero or not.

So what are you saying? I'm the chode becuase I jump to conclusions? How else am I supposed to increase my post count?

Let me just take this opportunity to link Tripping the Rift for everyone here who hasn't seen it yet. (Main character is named Chode.)

If you've got the bandwidth, the "Love and Darph" pilot is worth the download.

Fools + Money = Easily Parted.

-Zeke

http://www.kenner.la.us/mason/bomb.jpg

This BBS has been a great source of links for submitting to www.bluesnews.com lately. I sent him the link for this picture yesterday and he printed it today. Loved his link text... "They set up us the bomb."

I think this is the fourth time I've sent him a Link of the Day that I originally saw linked on this BBS. Thanks, everyone, for great links.

That, my friend is an excellent picture. I & half my office lost it. Best comment: "The Pakistani nuclear weapons delivery system has not quite been perfected."

-Zeke

That bomb pic makes me think of one of my favorite forwards I got.

Before you look at the attached pic, note the guy on the right is trying to disarm a bomb.

Well at least the don't lie...
"This system is at the same time deceptively simple and enormously accurate in the hands of people who know both how to operate it and what they are looking at."

OK, point taken. It just never ceases to amaze me how gullible some people are. Gullibility seems to be proportional to wealth too. I hope I never get too wealthy .

I've seen this believe it not.

Calvin

We have a bank in town that just had some software developed that they claim they will only use in the next few years, so they requested specifically that we write it using only one digit for the year! Of course we used the full year and only display the one digit they need. You all know how that works "We are only going to use this for a year or so.....ok now that that year is over, we need to use it permanently...is this a problem??

ED7

"We are only going to use this for a year or so.....ok now that that year is over, we need to use it permanently...is this a problem??

Not if the invoice for the $100K upgrade is paid in full for the next year...

Yea that would be nice! I have yet to break my first 100K deal...the most our small independant firm has ever been paid for software design is 82K, which is pretty good for a firm as small as ours!

"Not if the invoice for the $100K upgrade is paid in full for the next year..."

Yeah, unless you are working for a military contract. My new job is working on a contract for software used by all branches of the military, each who wants a different feature set. The funniest part is, there is one department paying for the contract, one deciding what it’s supposed to do, and another who actually uses it! This means the requirements are set without a ground in reality (not based on price or usability), and come from at least five simultaneous directions at once. To top it all off, when I started this job a month and a half ago the former programmers had implemented the different functionality for each service with out any type of OOP and finally had to make different code streams. Needless to say I have straightened THAT out. . . Anyway, they make these ludicrous demands and we pretty much have to just follow along because we are under "contract". I would be furious at the whole process if it wasn't so funny all the time.

The guy is probably very clever - he knows there will be enough complete fruitloops out there who will buy this nonsense that he never needs to work hard again.

But it does just make you want to go "WWHHAATTT???!!!!"

It's not NECESSARILY as stupid as it seems. One way to ensure that you never have any rollover problems is to make sure that rollovers happen often. That way, you're going to have to code for them properly, and you're more likely to test them. For systems that only deal with data within a short window, I've often thought that using a single digit for the year would avoid Y2K type problems; once you've got the rollover working, it will pretty much work forever.

Of course, it's also possible that they haven't thought about any of this, and they really are as shortsighted as they seem!

Richard.