In Reply to: Re: dualdisc and unidisk posted by Martin419 on October 11, 2005 at 07:56:07:
Martin incorrectly says "With regards to thickness, all that the manufacturers need to do is make sure their machines are designed with Redbook CD in mind, since DualDiscs don't exceed 1.5mm. And 1.5mm is within CD spec."All CDs are 1.2mm, all DVD-Videos even 2 sided 2 layers (see chart in link) are 1.2mm, all DVD-Audios are 1.2mm, all SACDs are 1.2mm, but DualDisc is 1.5 - 1.6mm.
All DVD-Video, DVD-Audio, SACD and CD equipment is designed to play 1.2mm discs and 1.2mm discs only, they have a tolerance of -.1mm +.3mm due to irregularities and slightly defective discs. Because of this tolearance it is physically possible to play DualDiscs but the equipment was not designed to be misused this way.
At 1.5mm a DualDisc is at the maximum allowable tolerance and if the disc goes over even a fraction of 1.5mm the spindle will break, as there is no more room. No product in the history of mankind has ever been designed to work at the maximum allowable tolerance and some DualDiscs and DVD Plus are actually thicker than 1.5mm.
That is why I will only buy DVD-Audio's until I can replace my DVD-Audio player with a DVD-Audio player that is DualDisc compatible. We should have some around Christmas.
Once I have a DualDisc compatible DVD-Audio player I will check out DualDisc releases until them I am not taking the risk!
Here are some charts from Disctronics that show why we are afraid, very afraid to put DualDiscs in our prized DVD-Audio players!!!!!
Combination disc formats
http://www.disctronics.co.uk/technology/dvdintro/dvd_hybrid.htmDVD Disc Layout & Formats
http://www.disctronics.co.uk/technology/dvdintro/dvd_formats.htmCombination disc formats
The SACD/CD Hybrid are read from the same side: CD layer on bottom (from non-label read side) and SACD layer on top. Thus the laser shines through the translucent SACD layer at a different and angle and thickness to read the CD layer at the 1.2mm CDs require. Total disc thickness is 1.2mm.The DualDisc / DVD Plus is 2 sided so the DVD Side is .6mm and the CD side is .9mm thus the laser hits are wrong angle as CD specs require 1.2mm and very excessive error correction is needed to play the CD side. Total thickness is 1.5mm.
DVD Disc Layout & Formats
All DVDs whither 1 or 2 layers or 1 or 2 sided are DVDs 1.2mm. All DVDs contain two .6mm substrates on a single layer DVD only one contains data, the other being a blank disc.Happy listening,
Teresa
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Follow Ups
- Wrong! CDs are 1.2mm all DVDs including 2 sided 2 layer DVDs, PROOF INSIDE!!!! - Teresa 17:53:37 10/11/05 (7)
- Re: Wrong! CDs are 1.2mm all DVDs including 2 sided 2 layer DVDs, PROOF INSIDE!!!! - jimby 22:45:14 10/11/05 (6)
- Some corrections to your observations --- - Teresa 18:07:54 10/12/05 (0)
- Re: Wrong! CDs are 1.2mm all DVDs including 2 sided 2 layer DVDs, PROOF INSIDE!!!! - levine_jonathan@hotmail.com 06:44:07 10/12/05 (3)
- Re: Wrong! CDs are 1.2mm all DVDs including 2 sided 2 layer DVDs, PROOF INSIDE!!!! - Martin419 08:42:20 10/12/05 (2)
- Re: Wrong! CDs are 1.2mm all DVDs including 2 sided 2 layer DVDs, PROOF INSIDE!!!! - levine_jonathan@hotmail.com 10:01:57 10/12/05 (1)
- Perspective . . . - Martin419 12:59:36 10/12/05 (0)
- Hi jimby - can I ask a question? - Christine Tham 01:54:11 10/12/05 (0)