[JaZZ]

Quote:

Originally Posted by nautikal /img/forum/go_quote.gif The vibration is caused by high frequency wobble. Are you going to back up your statement with logic and scientific principles, or are you just going to say the equivalent of "reducing the mass on the outer portion of the disc will reduce vibration because you reduce the mass on the outer portion of the disc?"

By reducing the amount of mass around the circumference, you lower the moment of inertia of the outer section and (thus) reduce the disk's damping requirement. There's less mass available to excite wobble (= vibration). It's not the inner section of the disk which excites vibration (by inertia and centrifugal force), but the outer section, which is much more affected by centrifugal force.
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[Wmcmanus]

(((Yawn))) What was I going to say again? Oh ya, that I've compared trimmed and non trimmed CDs and that the trimmed... oh never mind!

 

[JaZZ]

Quote:

Originally Posted by rsaavedra /img/forum/go_quote.gif Well I didn't ask you But it isn't biased at all. It's simply that neither one has provided evidence supporting their claims. There is no bias or subjectivity in assessing that.

So it is unbiased and objective?

Your subjectivity and bias lies in the criteria you apply for your categorisation. I'm not buying every marketing and pseudo-science claims as well, but I'm open to concepts which have some likeliness to work, the more so if they get positive reviews from people whom I trust. BTW, I'm not even sure that the vibration scenario applies here -- I rather bet on the scatter-light scenario.
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[nautikal]

Quote:

Originally Posted by JaZZ /img/forum/go_quote.gif By reducing the amount of mass around the circumference, you lower the moment of inertia of the outer section and (thus) reduce the disk's damping requirement. There's less mass available to excite wobble (= vibration). It's not the inner section of the disk which excites vibration (by inertia and centrifugal force), but the outer section, which is much more affected by centrifugal force. .

Lowering the inertia of the outside of the disk means it takes less force to cause wobbling, which you want to prevent.

And there's no such thing as centrifugal force, so I'm not really sure what you're talking about.

 

[Uncle Erik]

Wouldn't the results of trimming vary between each and every different transport?

And I'm not sure why this can't be settled by ripping a disc before trimming then ripping it again after. Have the computer compare the ones and zeros between the two.

 

[edstrelow]

Quote:

Originally Posted by rsaavedra /img/forum/go_quote.gif I disagree, I really don't believe that vibration reduction is highly likely. Precisely because I think most CDs come pretty well made already, well round and concentric. The company making the device should show (verifiable) numbers indicating what the variance and distribution are about those construction metrics in standard CDs, and how much better the device leaves those metrics in the CD after the treatment. If they haven't done that, (provide evidence instead of simply words,) then they are speculating as wildly as the rainbow foil which respect to what each device does respectively. Then there is of course the issue of whether whatever changes in those construction metrics they can achieve does really reduce vibration and to what extent, and if it does have any measurable effect on CD playback. But first things first.

This a poor argument.

You can check the vibration yourself on any disc with a portable cd player. It is either perceptible or not. That's good enough for me and the trimming caused by this machine cuts down the vibration in an obvious and detectable manner. Some others hear report that they can hear their discs rattling around in their players, expecially at high speeds.

If you can't trust your own judgement on an issue like this based on hearing or feeling vibration then you might as well forget about being an audiophile since the subtleties of what makes good sound will surely elude you.

 

[rsaavedra]

Once again, neither company has provided evidence supporting their claims. That's all that matters, and that's all I'm assessing. They are in the same speculative status about their claims. If someone thinks there is subjectivity in that assessment, that is irrelevant. It won't change anything one bit. Such opinion won't provide any evidence in favor of any product, so it won't change the status of either company with respect to their unsupported claims.

 

[rsaavedra]

Quote:

Originally Posted by edstrelow /img/forum/go_quote.gif This a poor argument.

For a second I thought you had used that sentence as an introduction to the rest of your post

 

[rsaavedra]

Quote:

Originally Posted by edstrelow /img/forum/go_quote.gif If you can't trust your own judgement on an issue like this based on hearing or feeling vibration then you might as well forget about being an audiophile since the subtleties of what makes good sound will surely elude you.

I don't have to forget about being something that I am not. What is your definition of audiophile?

 

[JaZZ]

Quote:

Originally Posted by nautikal /img/forum/go_quote.gif Lowering the inertia of the outside of the disk means it takes less force to cause wobbling, which you want to prevent.

It is the mass/inertia which causes wobbling, together with centrifugal force.

Quote:

And there's no such thing as centrifugal force, so I'm not really sure what you're talking about.

No such thing as centrifugal force? My native tongue is German, and every dictionary available sais it's the right translation. Google.
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[hempcamp]

Quote:

Originally Posted by edstrelow /img/forum/go_quote.gif If you can't trust your own judgement on an issue like this based on hearing or feeling vibration then you might as well forget about being an audiophile since the subtleties of what makes good sound will surely elude you.

This made me chuckle.

Likewise, I think you might as well forget about being an audio enthusiast if you don't take the time to understand why things that sound good sound that way, and what realistic things can be done to improve on that sound.

You should never trust your own senses independent of your intellect. That's how magicians and snake-oil salesmen (not just in the audio industry) make their money.

This reminds me of the superstitious rejection by housewives (and househusbands?) all over the world of Compact Florescent Lighting. So many homeowners claim that CFL lighting doesn't look right, even though the measurements and good science show that it should. Yet put them in a blind test and they can't tell the difference (or choose CFL as the better source of light!). This Popular Mechanics piece is just one example of many that I've read.

Also reminds me of why those various body part enlargement companies still have enough money in the bank to buy late night TV infomercials...

--Chris

 

[nautikal]

Quote:

Originally Posted by JaZZ /img/forum/go_quote.gif It is the mass/inertia which causes wobbling, together with centrifugal force. No such thing as centrifugal force? My native tongue is German, and every dictionary available sais it's the right translation. Google. .

Centrifugal in Latin means "center fleeing." This would imply a force that pushes an object away from a circular path. The real force you are talking about is centripetal force, which means "center seeking" in Latin. This implies a force that causes an object to take a circular path. "Centrifugal force" is merely the absence of centripetal force. See here.

Do you know what inertia means? Inertia is the property of matter by which it retains its state of rest or its velocity along a straight line so long as it is not acted upon by an external force. Saying inertia causes movement is like saying a stabilizer on a ship causes listing.

 

[stevenkelby]

Inertia does cause movement.

If a disc is spinning due to a motor spinning it, then the motor is disconnected, the disc will continue spinning (moving) for a time. Why? Due to it's inertia.

The cause of the movement after the motor is disconnected is inertia. The inertia of the disc.

 

[nautikal]

Quote:

Originally Posted by stevenkelby /img/forum/go_quote.gif Inertia does cause movement. If a disc is spinning due to a motor spinning it, then the motor is disconnected, the disc will continue spinning (moving) for a time. Why? Due to it's inertia. The cause of the movement after the motor is disconnected is inertia. The inertia of the disc.

Right. But technically it's not causing the movement... it's just preventing the object from stopping. Inertia isn't going to cause anything to begin wobbling, spinning, etc, and that's really what I meant.

 

[Mher6]

Quote:

Originally Posted by nautikal /img/forum/go_quote.gif Right. But technically it's not causing the movement... it's just preventing the object from stopping. Inertia isn't going to cause anything to begin wobbling, spinning, etc, and that's really what I meant.

The disc will naturally wobble; it's impossible for the disc to spin perfectly horizontally unless you have a force "pulling" down on the disc. Centripetal force does NOT cause the disc to wobble. I only read a few posts, so if I'm talking about something that isn't related to what you guys are arguing about, just ignore this comment.