Slightly off topic : I don't think sound quality has anything to do with the thickness of the LP. I have a good number of 120-140 gm records and they sound beautiful (easily as good as the 180-210 gm LPs if not better)! "180 gm audiophile vinyl" is just a marketing gimmick. The only advantage is that those LPs don't get warped that easily.
Once my chin grew up to the level of our study table, I was granted the permission to play the turn table, own self. Since then, been spinning flexi wafer thin jingles to biscuit thick vinyls, and interestingly some of those LPs were 15-20 years older than me.
So far, Im unable to distinguish the sound quality difference between that fat & slim ladies!! When it comes to distinguishing that extra fine audio quality, I think, Im still wet behind my ears!! . Yet, my vote goes to those heavy weight records, for various other reasons.
And, what I like in those thick disc is, I believe they keep-safe-long the music even after 50+ years, whereas the slim ones got easily succumbed to scratches, groove wear etc etc. I bench mark this with my, equally played 4 variants of Tchaikovsky pressed between 1955-2000. In 20 years, those extra thin fluffy Madonnas & Jacksons discs of mine , have fairly well lost their output now. A random scan over my collection list also infers the same.
Im not sure if I could attribute this reduced life, to the high elasticity/malleability and low hardness of the raw material, which is a key spec to achieve slim plates. In this era of cost reduction & plastic curb, and If the SQ were to remain the same immaterial of thickness,then, the industry would be all out to encourage flexi-discs; wonder why?
Having said, If I were to pass on my vinyls to next generation, and want them continue singing for few more generations, then I would keep my bet on those fat bottom ones!!.
