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Why are records still warped?

This is more of a grouse than anything because I know the molding process won't ever be perfect. Still, here we are in the 21st century in the midst of a vinyl revival. Artists get it and are trying to satisfy us geeks with tasty pressings.

Cases in point are Bennett & Gaga's "Cheek to Cheek" and Lennox' "Nostalgia." Ordered both of them in (live in the sticks so no local source) and one dished, the other warped. Neither are unplayable, but both conditions are audible. Disappointing to say the least on such outstanding efforts.

The same week they arrived, I got copies of Hampton's "Silver Vibes" (mono) and Mendes' "Look Around" used at a swap meet. Perfectly flat with outstanding fidelity, especially considering their age.

Many of my "not" Golden-era pressings from the mid-70s through late-80s also lived up to expectations when I got them home. Many more did not, and that's why I ended up jumping on the CD bandwagon with a Sony CDP-101 in 1983.

In 2015, my digital playback deck is about 1000% better, CDs are better, SACDs are even better still, HD downloads can be superb, but still none of them best vinyl at its best. Unless it's warped.

We have the technology, know better and can better control the process. So, what is up with the warp thing? Is it laziness, budget or what?!?
effischer
wattsperchannel
142 posts
 
Not necessarily. There are many variables involved. The wider wall stock will reduce the pressures required to make the puck which can result in lower internal stresses so it helps in that regard but the more plastic the more shrink which as you state could make things worse. I have no direct experience with how these to countervailing influences effect records.

Complex finite analysis models are used to predict these things but they are only so accurate. There is no substitute for prototyping the mold and making actual parts to get the best result.
slaw's avatar
slaw
21,292 posts
 
Lowrider57: Your post was my impression. I felt that quite a lot of the warps were due to taking the lp off the press too soon. Your post is a similar finding.
melm
1,074 posts
 
A 180g record, while offering no advantages (except marketing, perhaps) requires more time to cool down. Failure to allow sufficient time for cooling down seems to be a major cause of warping.

Actually, if most of your records are 120g or so, 180g records are a disadvantage for some who are scrupulous about their SRA. More adjustment.
ttweights
50 posts
 
Does any one recognize the fact that the SRA is always changing as you play a warped record?

On a true high end turntable one can hear warps very easily, there is a change in sound (SRA) as it rides up then down and compresses the stylus, it is acting as a suspension system.

Take the warp away and the cartridge WILL track to groove very much more effectively is simple physics.

Let the stylus read the groove and any cartridge can perform a lot better.

This is more and more prevalent with heavier cartridge down forces...
ketchup
698 posts
 
TTW, it's not just the movement of the suspension system that causes a change in SRA when playing a warped record. Even if the suspension didn't move at all, SRA would change as a cart tracked a warped record since the record surface is not horizontal as with a flat record, but angled one way as the cartridge goes up the hill and angled the other way as the cartridge goes down the hill. The tonearm angle also changes when going up the hill and down the hill which adds more changes in SRA. So, all three things add up and change SRA when tracking warps: The angle of the record surface, the angle of the tonearm, and the angle of the stylus as the suspension deals with the warps (there is more force on the styles/suspension when going up the hill and less force on the stylus/suspension when going down the hill).
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