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In Reply to: I agree completely and this is what a should have been done with both DualDiscs and CD Mats posted by Teresa on August 19, 2005 at 10:50:57:
>> There should have been long term testing done and CLEARLY this was not done. <<You are totally wrong there. The DualDisc consortium undertook a whole matrix of test scenarios. Many different players. A full reliability study using many independent samples. They know *exactly* what to expect in terms of reliability.
Follow Ups:
But had they done "long term" testing they would have foreseen all the problems and issues way before they happened.One does not design a product to work at the maximum tolerance (1.5mm) and slightly beyond and not expect something to break! That is just not logical.
There is a simple fix coming though DualDisc compatible CD and DVD players that will move the maximum tolerance to about 1.8mm to cover slight manufacturing defects and variances.
The DualDisc consortium was totally blowing smoke and you are willing to risk your equipment, as you actually believe them and not the designers who made your equipment, why? The fact is the DualDisc consortium rushed DualDisc to market without adequate testing to try to combat illegal downloads by offering extra content they cannot get on the web.
Until you can get a DualDisc compatible DVD player you are playing DualDiscs totally at your own risk.
Teresa: I suggest you get the facts directly from the DualDisc consortium (re. their extensive pre-production QC testing matrix). If you won't do that, then please put your pipe down.b.t.w. Not one manufacturer says how a machine can "break" by playing a DualDisc: Not regarding 'rotational inertia' issues. Not regarding 'laser focussing'. Not regarding 'error correction'. Not regarding disc 'thickness'. Not any of these.
Granted, some disclaimers do allude to the possibility of one of the sides getting scratched by a slot loader's pull-mechanism. But I'm not worried about that. And FWIW, the SUV'S slot-loader I did try the Keane title plyed it fine; it did not get stuck; and it did not scratch the top side of the disc. (I can't speak for other people's experiences with slot-loaders of course).
The DualDisc consortium or the people who make our DVD, SACD and CD players?I choose caution and heed the warnings of the equipment manufacturers and reframe from putting a DualDisc in my DVD-Audio player.
You on the other hand throw caution to the wind and believe the DualDisc consortium and actually play DualDiscs in your DVD-Audio player.
It's a choice and I choose to be safe and that's all it boils down to.
Martin, you've laid claim to having an engineering background. Change out of your DuaDisc cheerleader uniform for a few minutes and try to think like an engineer.Earlier you brought up to Christine > > mechanical reliability analyses and statistical correlation; MTBFs, FMEAs etc.. < < Let's talk about that.
MTBF is an average, typically determined through prior experience and estimates based on typical usage.
FMEA is a predictive analysis based on the system's intended use.
Once you take a device outside of its design envelope, MBTF and FMEA are pretty much useless!
As an example - the motor in my Yamaha racebike contains many parts, most of which have MTBF ratings based on typical usage. I expect that FMEA (or something similar) was performed in order to determine spares allocation and the like, but again, this would be based on typical usage! Yamaha warrants the motorcycle to be reliable in a typical-usage situation.
The way I use the motorcycle is far from typical. Since it is a race machine, I run the motor near redline (for maximum power output) almost constantly. I am not exceeding the tolerances, in that I do not exceed maximum rpms allowed, but since I am running it near maximum tolerance at all times, it is not typical usage so MTBF means NOTHING! Since I am pushing the motor as hard as it can be pushed without exceeding tolerance, I expect things to wear out more quickly, go out of tune, lose efficiency. This means I am frequently doing maintenance and replacing parts that would not have worn as quickly if I were using the product at less than maximum tolerance. To that end, Yamaha does not warrant the motorcycle when it is used under race conditions.
So - the disc players we have today were designed for a typical usage scenario of CDs and DVDs which are at, or very near, the specified 1.2mm thickness. MTBF is based on this. Any FMEA would be based on those design parameters. There is a maximum tolerance of 1.5mm for disc thickness, but since it is maximum, there would not have been an expectation that many discs would reach maximum. In the opposite, in fact - a close-to-1.5mm disc would tend to be a rarity prior to DualDisc.
Now comes DualDisc, with a MINIMUM specification of 1.42mm, up to 1.5mm maximum. I'll be generous and assume for discussion purposes that there are no longer any discs that exceed the 1.5mm maximum.
1.42-1.5mm is within the tolerance range, but it's MAXIMUM. Feeding a player designed for 1.2mm discs a steady diet of discs at maximum tolerance is outside the typical usage scenario, which means, just like the situation with my racebike, that MTBF becomes meaningless, and any predictions based on a FMEA would be useless.
Again, just like my racebike situation, it's reasonable to assume that regularly running the player at or near its maximum tolerance may cause parts to wear out more quickly, cause alignments to drift, and create maintenance or replacement situations that might not have occurred if the player hadn't been regularly run at maximum. Given this quite reasonable assumption, player manufacturers are well within their rights to say that they will not warrant the players if the players are used in this manner.
So, until the player manufacturers have had the opportunity to do long-term testing, and FMEA with new parameters, Teresa is absolutely correct - you are incurring risk by playing DualDiscs.
BTW, if you think that the DualDisc consortium did long-term player reliability testing (as opposed to simply testing for a minimum playback compatibility level on various players), then YOU are the one smoking something, and you should put the pipe down.
/ . . . /"Meridian does not guarantee that the CD-compatible side will play without audible errors in all players. However, attempting to do so will cause no harm or damage whatsoever to our players."
/ . . . /
[And now re. the THICKER & HEAVIER DVDPlus: ]
"DVD-Plus. Meridian is also aware of another 2-sided DVD-based disc format called DVD-Plus or OneDisc, which is thicker than DualDisc (typically 1.55mm). In the few cases we have tested, both CD-compatible and DVD-compatible layers appear to function in all our players, and no harm can come to our players by trying them."
Meridian's information about DVDPlus is incorrect:
Maybe Meridian did their own measurements.b.t.w. I have a DVDPlus album (Kasabian) and it feels thicker than my DualDiscs. (It plays fine in all my players.)
You don't own a Meridian, do you?
You are being silly.
.
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