While dated, the information is pertinent to many of the older pressings and likely applicable to more modern pressing plants that use similar designs. The AHRC Research Centre for the History and Analysis of Recorded Music (CHARM) has a website that includes a section on record defects that originally appeared in The Gramophone (December 1931 and January 1932) by William D. nload.aspx) seems to indicate that the tolerance for thickness is +/- 0.13mm (0.005 in.) so I'm not sure what the actual standard might be. However, the IEC specifications included in the manufacturing standards posted at the GZ Media website (. (0.25mm) so it seems that all of the records I sampled were within that specification. I think the tolerance for thickness is specified as +/- 0.01 in. I found a RIAA publication from Aardvark Mastering ( ) that includes tolerances for record manufacturing but the specifications for LP records is not clear. The most uniform pressings were within +/-0.05mm. The majority of my LPs were within +/-0.10mm at the outer null point. One record had a difference of 0.25mm! Other LPs, regardless of weight, had a nearly uniform thickness. The quality of the pressings also varied, which isn't surprising, but I found many LPs with a difference of over 0.15mm thickness along the groove. The other oddity is that the discs in a couple of heavyweight (180 gram) double-LP sets were obviously from very different pressings there was a 20 gram difference between the two LPs! I noticed certain records were noticeably heavier or lighter for the measured thickness. The most variability in thickness for a given weight seems to occur in the range of 130 to 150 grams. Quality Record Pressings has a web page describing some of the reasons for the phenomenon. I found record thickness could differ by more than 0.25 mm for a stated weight and weight could differ by as much as 20 grams for a given thickness. There was a fairly wide range of thicknesses for a given weight, and vice versa. The other surprise was that the thickness-to-weight relationship, while linear, isn't as clean a relationship as I expected. That is, if there's a release I really want and a heavyweight pressing is the only one available, I'll purchase it, otherwise I usually buy standard-weight pressings. I don't usually seek out 'audiophile' releases so it appears that the number of heavyweight-only releases is becoming more common. There's a rise in the percentage of records weighing 180 to 200 grams and that also surprised me. But the majority of my LPs (>50%) weigh 110 to 120 grams, with few weighing 160 to 170 grams. I had assumed that most LPs weighed between 120 and 150 grams, which I'd seen posted on several websites.

For example, I was especially surprised at the distribution of records based on weight/thickness. The graphs and tables below (also posted in my gallery at the AudioAsylum website) speak for themselves but I did find some interesting, even eye-opening results. Thus far I have measured 200 LPs out of the 1400 LPs I own so it's just under a 15% sample. The weights were rounded to the nearest 0.1gm. The thickness measurements were taken at a minimum of three and up to six locations along a 118-120mm radius (close to outer null point), averaged and rounded to the nearest 0.05mm. On average, I sampled two to three LPs a couple of times a week.įor the measurements, I used a Fowler digital thickness gauge (+/-0.01mm) and a Durascale D2 digital scale (+/-0.01gm). The sampling wasn't a true random sample but my tastes are fairly eclectic and the sampling occurred over a one year period playing a variety of music.

A caveat is that classical and jazz recordings are not well represented, so if pressings of those genres are not typical of other music, my sample may not be applicable. I consider my vinyl collection to be fairly representative of someone who has collected vinyl for over 40 years. So I started weighing and measuring LPs and have accumulated a representative sample with a few simple statistics. The limited information that is available is simply being repeated with no specific references. Over the years I've tried to find information on the relationship between LP record weight and thickness to help in setting VTA/SRA for a range of record weights, but so far my Google and Bing web searches have turned up nothing of any real value.

LP record weight and thickness measurements and observations (updated January 2017) I recently posted the results of my sample of 200 LP records at the VinylAsylum forum but thought the forum members here at VinylEngine might also be interested, so here are my findings:

Weight of vinyl record