First time I heard about 180 gram vinyl was about 1.5 years ago when I bought Metallica’s “Black Album” . I don’t remember exactly where I bought it, I just know I purchased it online and it was advertised as a Deluxe Vinyl, that sounds louder and heavier. It was more expensive than “regular” 120g – 140g vinyl, so it took a little bit longer to convince my wife to give me her permission to buy:).
Definitely, this particular record sounds better, looks much better, but does the weight make the sound different? No, it doesn’t. The heavier weight gives the vinyl an ability to withstand the deformation caused by normal play better, but sound is better because of recording higher speed, 45rpm.
So, why does 45 rpm vinyl sound better? There is a very good explanation by Kevin Gray from AcousTech Mastering, I found online. In accordance to it, the higher the recorded level and frequency, the greater the groove curvature. Curvature is not always a problem on small diameter disks, but as groove moves toward the center its relative speed slows down and curvature increases. The quote: The result is actually a loss in high frequencies, and increase in distortion as the groove moves to the center. The problems start when the curvature of the groove equals or exceeds the diameter of the playback stylus. What can be done about it? Many things have been tried, but there is no “magic bullet”. Keep the recorded volume to a reasonable level (read: On scale on the meters) is the first thing. Play the record back with an elliptical or line-contact stylus that has a smaller tip radius. And, if possible, make the record short enough to keep the music away from the very end of the disk. This isn’t always possible, of course.
So, if we spin the disk at 45rpm, we have a 35% increase in groove velocity at any point on the disk, the groove still slows down as it moves inward, but the effects are greatly reduced. The only problem here is that we also reduce the recording time by 35%. That’s why such long play albums like the one I bough, recorded at 45 rpm, come with four LP’s instead of two. I think that’s worth it, because I can hear the difference. I prefer to buy a disk that sounds much better, but off course it costs more.