Well, I can say how test pressings were used at Mercury Living Presence, cannot speak for others 
because I never heard the details first-hand but I bet most other classical shops operated the same 

Test pressings were a tool to make sure the master was correctly plated and production parts were 
not carrying defects. Plus, since RCA pressed the MLP records (superior plant, superior vinyl 
compounds, Mercury plants never got up to snuff until Philips took them over), this was a way to 
make sure the plant was doing exactly what they said they would do.

Test pressings were distributed to the producer, the engineer and the mastering guys. Everyone was 
encouraged to at least spot-check and the producer listened to every test pressing all the way 
through, comparing with notes made during the mastering session.

Now, the fact is that production LPs don't sound as good as the test pressings, which is why I asked 
my original question -- what makes the production LPs generally noisier and less punchy? I'm 
assuming that the plants pulled out the "maker's mark compound" biscuits for the test pressing and 
that production itself wore down the stampers and mothers, and perhaps the simple act of being 
quickly sleeved effects production vinyl.

Back in ye olde days, a test LP would arrive as a white-label affair, identifiable only by the 
cutting marks, in a rice-paper-like sleeve in a paper envelope. There was a separate test press for 
each side of a production LP. The general way things worked at Mercury, a clerical person would 
pencil in the catalog number on the white label and distribute copies, including one for the files. 
When the QC listening was done, it was done with a stop-watch so that times could be known for 
problem, which were noted. Visual inspection was also done and vinyl "zits" or clearly-visible 
groove problems were measured from edge and noted. The rejection rate was somewhere south of 10% 
most of the time.

The same care was taken with mono, because mono out-sold stereo even with classical music until the 
mid-60's when retailers stopped carrying both formats (see John Eargle's JAES article).
Stereo/Mono Disc Compatibility: A Survey of the Problems
Volume 17 Number 3 pp. 276-281; June 1969

The record industry is now phasing out the mono disc, and the subject of compatibility has once 
again been raise as it was with the introduction of the stereo disc ten years ago. Then, the problem 
centered largely around stylus-groove relationships and considerations of trackability; this time 
the problem is mainly concerned with the way a pair of stereo channels combine to yield a suitable 
mono channel.
Author:   Eargle, J. M.
E-lib Location: (CD aes3)   /jrnl6877/1969/6797.pdf
available at

-- Tom Fine

----- Original Message ----- 
From: "phillip holmes" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, July 03, 2007 1:24 AM
Subject: Re: [ARSCLIST] LP pressing question

> I've been told by collectors and people that were in the business, that test pressings were 
> pressed in very low numbers, IE, 100-200 copies for the musicians, A&R people, producer, big wigs, 
> and the like.  Every test pressing I've seen had a plain white label with just the bare basics 
> typed or handwritten, and I only have 2 major label test pressings and 3-4 "audiophile" test 
> pressings.  The jacket had a pasted on (typed or handwritten) note with just the basics--tracks 
> and artist stuff.  If anyone wants a picture, I'll send one.  But it's impossible to confuse a 
> white label promo with a test pressing.  Obviously, the idea of the test pressing is to give fair 
> warning about what's going to be on the record.  It supposedly gave the musicians the opportunity 
> to sign off on the final product, but this really was a micromanagement tool for the front office 
> types.  I can imagine some imbecile in management spitting his coffee all over the board room 
> table while listening to Black Sabbath for the first time.  "Fairies wear boots?  What the hell is 
> this crap?  Who signed these bozos?  I need to fire the A&R department".
> Phillip
>>                             Roger
>> Tom Fine <[log in to unmask]> wrote: Why do most test pressings that I've heard sound 
>> better than a bought-in-store version of the LP? Did the plants do something special for the test 
>> pressing or use a "brewer's choice" biscuit compound or is it more a random chance of having a 
>> further-down-the-production-run copy in a store and thus worn stampers? Where I've been able to 
>> compare a master laquer to a test pressing to a bought-in-store version of the same 
>> cut/matrix/whatever, the test pressing usually sounds pretty darn close to the first cut but the 
>> production disk sounds inferior, usually lower s/n ratio and noisier surface. This was less true 
>> in the one case I've been able to compare all 3 for a modern LP reissue and I assume it's because 
>> a modern reissue that appears at retail will be pressed with more care on better vinyl and fewer 
>> copies will be made per stamper, but I might be wrong on that.
>> In some older examples, late 50's and early 60's, the retail version vinyl seems to definitely be 
>> a different compound from the test pressing, which more resembles modern, "softer" 
>> quieter-playing compounds.
>> -- Tom Fine
>>        ---------------------------------
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