 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
Had a shock last night when we viewed a 15 year old DGG PAL laserdisc. It had horizontal white streaks appearing randomly in the picture, worse in some places than others, but consistent throughout both sides. Is this noise laser rot? If so, how prevalent is this?My first impression was it was the player or the set up but another LD revealed no such flaws.
Note that this was a PAL LD played on a Pioneer D-925. Most LDs in this collection are NTSC and the Pioneer HLD-X9 is used for them and so far this phenomenon has not been seen elswehere.
John
Peace at AA
Follow Ups:
Generally, my rotted discs will be worse on one side than the other, but this has not been universally true. Rot usually first manifests itself as multi-colored speckles, and if the oxidation becomes bad enough, the picture can become scrambled and the disc unplayable. I believe I only have one side of one disc that has suffered that particular fate, though.Laserdiscs are far more vulnerable to rot and aluminum layer oxidation problems than CDs or DVDs because they have analog picture information. They lack the interweaved data and robust error correction of the digital formats. In fact, the laserdisc format has no real means of replacing lost picture information; hence, the occurence of dropouts and other problems that DVDs are largely immune to. There were also a number of problems related to laserdisc manufacture over the years. Some were due to the pioneering nature of laserdisc, the first consumer optical disc format, but others were simply due to shoddy manufacturing. Rotted discs were still being produced at the Sony pressing facility in Terre Haute, Indiana, well into the 90's.
I do have one disc that a friend sent me that has a weird manifestation of laser rot in that there are little horizontal streaks appearing randomly throughout the picture. On this disc, you can actually see that the aluminum has a mottled appearance from the oxidation.
Rotted discs will also very often have audio problems. Commonly, this will manifest itself as sort of a helicopter like sound, usually more noticeable on the analog FM tracks than on the digital tracks. I do have a few discs where the situation is reversed, though, and I don't know what's going on there.
On NTSC discs, particularly bad ones are DiscoVision titles, Technidisc releases, discs with the LDVS mintmark, and Pioneer Artists 8" discs. I have over 50 eight inch music video discs and would estimate that fully 20% of them have some sort of rot, in most cases, minor to moderate.
Todd
Just about 90% of the LDs in this collection were imported from Big Emma (bigemma.com) and the discussion below caused me to look again at the site. I had not bothered for ages because of the bad exchange rate we have had with the USD lately (improving now) + the high costs of freight across the Pacific Ocean.But I am surprised at the relatively high prices some are prepared to pay for used LDs - as much or more than a few years back. Most of us now have DVD players and, at its best, DVD can be slightly crisper than LD on the big screen. However the general run of DVDs appears no better in video quality than LD.
John
Peace at AA
As for video quality . . . DVD's have slightly greater resolution and when they are played on a good progressive scan player they can be quite impressive. The X9 fed to a scaler-de-interlacer is also quit impressive. Both look great on a digital projector.However, a CLD-97 or an LD-S2 fed to an excellent de-interlacer to a CRT projector makes for a very "film-like" image. Slightly less resolution than a DVD but very, very smooth with no digital artifacts.
The cost of such a set-up is astronomical, however. Besides, LaserDisc is dead and CRT projection is dying.Another cause for the prices is the fact that LaserDisc DTS soundtracks are generally better (they don't have to be, it's a choice made by the DVD guys on a disc by disc basis. . . sigh! Not to mention some DTS Lasers do not exist as DTS DVDs) things like Independence day on Laser still command a fortune.
I have both Laser and DVD since I have far too many Laser movies to replace, if they even existed as DVDs. It took a while, but after I finally got over getting a headache when I watched DVDs and could mentally block out the artifacts I found them as good as or better than LaserDiscs. When I then changed to a digital front projector (92X52 image) from a CRT rear projector I found I generally preferred DVDs.
I have "Independence Day" but it is only widescreen with AC3 audio. Not a great movie IMHO so I'd gladly sell it but I gather from what you say that it is a special edition with DTS soundtrack that is valuable?Not trying to start an argument but I disagree with your comments about CRT. Maybe it depends upon the breed of CRT but I can get genuine film quality with the Barco projector (after a Barco VSE40 has quadrupled), not so consistently out of the HLD-X9 on LD or Meridian 800 on DVD but from s-video tapings or direct view off digital satellite. We get 600 line resolution (PAL) on good material. It is only the odd DVD that levels with the best broadcast. Most irritating because I fail to see any excuse for poor video these days. Rant over.
John
Peace at AA
and of NTSC. I am very fond of PAL for broadcast (I assume given your other comments and your locale that your broadcasts are PAL). Given a quadrupler and good reception the picture should be excellent indeed.I used an S-VHS and a doubler to record in South Africa (also PAL). The results were also quite good. And I was able to rent a CRT projector for a bit. The resultant tapes were as good as anything I saw on Laser (NTSC) after I returned to the states (I kept the PAL player, the projector here was multi-system.) Perhaps better, it's been a while.
as pointed out previously, the most common manifestation is snow (by a very wide margin). Certain labels were prone to the problem but, to my knowledge, DGG was not one of them. Most experts blame quality control in the manufacturing process. You might be able to find another one on eBay, perhaps on NTSC . . worth a shot, though the chances were far better about 2 years ago.
Laser rot is caused by oxidation of the aluminum reflective surface due to air seeping into what is a sandwich of two polycarbonate discs that are glued together. The result can be a whole range of visible defects, typically "snow" (big multi-colored particles), weird streaks, etc. I suppose DVDs, CDs, SACDs, etc could "rot", but I have never encountered this phenomenon in these products; I've see a lot of rot in laser discs, and I'm not just talking about the state of Hollywood film-making.
Not sure about laser disc but one of my cd rot are tinny hairline cracks all over the printed surface. Placing it over a lamp I can see light coming through the cracks.Sam
what was the recording, John?Sam
... Leon Bernstein conducts "West Side Story" with Kiri Te Kanawa, Jose Carreras - "The Making of the Recording".Fascinating stuff watching Bernstein getting perplexed at the artists, Carreras upset because the union stopped work on the recording (going overtime was forbidden), ..... Some great moments. Of all the LDs I wished to preserve this one was high on the list :-( I think it is out on DVD but I paid full price for this LD so am unhappy about having to pay again. But then if the disc means so much, ......
John
Peace at AA
nt
This post is made possible by the generous support of people like you and our sponsors:
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2025, Audio Asylum, all rights reserved ]
