"Shaving" optical discs

[gene_stl]

I always enjoy Mat's videos anyway. The title of this one grabbed me and he shows the propaganda from a snake oil salesman who seems to be a biochemist who invented this system.

Naturally, it made the technologist in me wonder, if they were on to anything, though if what they are selling worked , the discs would be manufactured that way. In the first place.

Of course he compares two files and there is NO difference. If digital wasn't 100% accurate your bank would make mistakes. I have been using automatic teller machines since the late seventies and have NEVER had one make a misteak neither fer me nor agin me.

 

[Jim Shaw]

I have improved the 'sound' of any number of 1980s pop music CDs simply by playing them upside down.

 

[chi2]

I always enjoy Mat's videos anyway. The title of this one grabbed me and he shows the propaganda from a snake oil salesman who seems to be a biochemist who invented this system.

Naturally, it made the technologist in me wonder, if they were on to anything, though if what they are selling worked , the discs would be manufactured that way. In the first place.

Of course he compares two files and there is NO difference. If digital wasn't 100% accurate your bank would make mistakes. I have been using automatic teller machines since the late seventies and have NEVER had one make a misteak neither fer me nor agin me.

BTW, the name of the inventor is Dr. Erich Schrott. The German term "Schrott" means junk, rubbish, trash. Nice.

 

[tomtoo]

Looks like Dr. Schrott is the nephew from Dr. Hanebu.



Only for insiders sry.

 

[Apesbrain]

Green edge markers
Spray-on "enhancers"
Spinning de-magnetizers
Carbon fiber stabilizer discs
Plastic edge rings
Glowing stabilizer discs

... just one of many zany ideas from the late '80s to "improve" CD playback (some of which I fell for).

 

[sq225917]

Do some cds have the centre hole offset so it's not concentric to the disc edge, yup. Can this cause wobble in the mech, sometimes.

Does shaving the edge of the disc make it easier for the servo to read the disc, nope. Because the data track isn't concentric to the outside edge either, it's set from the hole,

Can the hole be off centre from the edge of the disc and the data track, yup, sure can.


At best this might improve wobble from grossly off-centre discs, but it ain't going to help read the disc better. The servos are just too good.

 

[DonR]

of course, the rebuttal is "...but....but... jitter...."

 

[egellings]

My understanding of CD playback is that the data is read from the disc, often in spurts, and stored in a buffer. The buffer's contents are then clocked out at a very stable rate to the DAC for conversion into analog. I saw one early player that had the disc oriented vertically, and I could see it spin through a window in the player's cover. It spun at an erratic rate, but the music came out steadily.

 

[DonR]

My understanding of CD playback is that the data is read from the disc, often in spurts, and stored in a buffer. The buffer's contents are then clocked out at a very stable rate to the DAC for conversion into analog. I saw one early player that had the disc oriented vertically, and I could see it spin through a window in the player's cover. It spun at an erratic rate, but the music came out steadily.

Yes, the read-out data goes through error detection and correction computations and then is fed into an output buffer whose control clock has nothing to do with the speed or accuracy of the read data.

 

[sq225917]

Yup, theres no jitter from the mech/servo in a cd player, its only a little buffer on the servo boards but it's big enough.

All that said I did lathe a cowboy junkies cd back in the day and it did a great job of removing the audible swish-swish of the out of balance spinning disc.

 

[mansr]

My understanding of CD playback is that the data is read from the disc, often in spurts, and stored in a buffer. The buffer's contents are then clocked out at a very stable rate to the DAC for conversion into analog. I saw one early player that had the disc oriented vertically, and I could see it spin through a window in the player's cover. It spun at an erratic rate, but the music came out steadily.

CDs are played with a constant linear velocity of 1.2–1.4 m/s. The spindle servo is controlled so as to maintain a steady data rate referenced to the master oscillator. The rate of rotation is highest when playing the innermost part (track 1) and slows gradually as the position progresses towards the outer perimeter. A player with an erratic rate of rotation seems like a strange beast.

High-speed CD-ROM drives work a little differently, but that's beside the point.

 

[gene_stl]

BTW, the name of the inventor is Dr. Erich Schrott. The German term "Schrott" means junk, rubbish, trash. Nice.

English Translation of “Schrott” | Collins German-English Dictionary

English Translation of “Schrott” | The official Collins German-English Dictionary online. Over 100,000 English translations of German words and phrases.

www.collinsdictionary.com

Actually a real person and really a biochemist.

 

[charleski]

Haha, this poppped up in the weekly snake-oil digest from Audiogon that I read sometimes for fun. It doesn't disappoint: looking down the thread we can find gems like, "The improvements were immediate and impactful. I know the term "sounds more analog" is overused, but does apply here."

"They can't all be wrong, surely?"
Yes, they can.

He mentions some people worrying about the CD shattering, but I think the major defect in this process is that breaking the seal at the edge of the disc will allow air molecules to diffuse in and may lead to oxidation of the aluminium reflective layer over time, causing the CD to become unreadable later on.

 

[mhardy6647]

English Translation of “Schrott” | Collins German-English Dictionary

English Translation of “Schrott” | The official Collins German-English Dictionary online. Over 100,000 English translations of German words and phrases.

www.collinsdictionary.com

Actually a real person and really a biochemist.

I like to tell the tale of the publication of the first DNA (and/or mRNA) "nonsense" mutation (i.e., first discovery of one of the three "stop codons" used to terminate protein biosynthesis. The de facto "discoverer" of the first one (mRNA sequence UAG) was a fellow called Harris Bernstein. In his honor the mutant was called Amber (Bernstein auf Englisch = Amber).

How nonsense mutations got their names

Mutants used to identify the other two stop codons were similarly, if goofily, named Ochre (UAA) and Opal (sometimes also called Umber, UGA).

I love stuff like this.

If you get really bored, check out the names of some of the mutants/genes described in the fruit fly, Drosophila melanogaster.
One of my favorites is a temperature-sensitive mutant called Hotshi Temperature sensitive mutants are typically identified with a superscripted ts.
So, yes, this mutant (gene) was wryly named:

Access Blocked

Fruit Fly Scientists Swatted Down Over 'Cheap Date'

When scientist discover something new, they sometimes get to name it. Scientists have labeled fruit fly genes things like "Cheap Date," and "I'm Not Dead Yet." But patients can take offense to this when they're diagnosed with having "Lunatic Fringe."

www.npr.org