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I think it's a stretch to say that Blumlein alone "invented" 45/45 stereo cutting. Keller et al have 
US patents on it and Bell Labs successfully used it to make experimental recordings in the 1930s, 
among them with Stokowski/Philadelphia. As I understand it, those were 45/45 and not 
vertical-lateral stereo recordings.

I do agree with your point about stereo mic'ing. Blumlein and Bell Labs came up with different 
approaches, and in fact Bell Labs experiements ended up favoring 3-channel stereophony as a more 
realistic reproduction of an orchestral sound source. The M-S and other crossed-matrix techniques 
were very firmly entrenched in Europe, to the point that people couldn't believe that 3 spaced 
omni's actually worked as well as they did for Mercury. Then a Philips engineering team tried the 
same technique in the mid-60's and got a series of very good-sounding recordings (somewhat 
un-Philips-like because they were both intimate and reverberant and not either-or).

As for 45-45, as I understand it, the whole reason Westrex could charge a license fee for all stereo 
cuts, in the 60s and I think into the 70s, was because they inherited the WECO patents from Keller 
et al from the 30s. Again, if Blumlein had exclusively "invented" 45/45, Bell Labs wouldn't have 
been granted a U.S. patent.

By the way, the theory of 3 spaced omnis is very different from 2-mic approaches. In the "M3" 
technique (as Philips called it), the center mic is paramount and is also the mono feed. The side 
mics are there more to add depth, width and height to the stereo image, not as much as primary 
sound-receivers (although they do perform this function for the side-most sound sources). The center 
mic must be focused perfectly of the image is diffuse. The side mics must be additive to the 
stereophony, as they are placed it becomes obvious where they are most additive (usually in a 
straight plane with the center mic). One of the reasons Mercury preferred having the mics on ropes 
vs. stands was that it was easier to move the sides at the same time (two guys on ropes). They used 
a surveyor's measure stick to record exact heights and tape measures to record exact distances from 
set points on the floor and walls.

Few would argue that there is much less setup hassle -- but also less range of adjustment -- when 
using a single-point stereo setup like a stacked Blumlein array or a single-point MS mic like the 
AKG C24.

-- Tom Fine


----- Original Message ----- 
From: "Paul Stamler" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, August 30, 2014 1:19 PM
Subject: Re: [ARSCLIST] Accidental stereo (again)


> On 8/30/2014 5:37 AM, Michael Biel wrote:
>> Because Blumlein was killed during WW II it is obvious that he was not
>> the engineer who Keith Hardwicke was referring to.  Besides, Blumlein
>> was in research and development, not in record production or cutting.
>> By the way, Blumlein was NOT the the one who discovered the art of
>> stereo recording.  Arthur C. Keller of Bell Labs was doing stereo
>> recordings in the Capitol Theater in 1927, four years before Blumlein
>> envisioned it.  Keller did stereo recordings of Stoki and the Phila in
>> 1931.  the Brits have done a dandy promotional campaign for Blumlein
>> which is why he is "credited by most" even if the "most" are wrong.
>
> But Keller and Blumlein were using very different recording techniques, so to say that either 
> discovered *the* art of stereo recording isn't accurate. Keller used spaced omni microphones, 
> while Blumlein used a pair of figure-8 microphones stacked on top of one another and pointing at 
> 90 degree angles to one another. The former technique creates the stereo soundfield from a 
> combination of intensity and phase differences, while the latter uses intensity differences only. 
> Blumlein also developed the "45/45" techniquee of cutting a stereo signal into a single record 
> groove; it became the standard format in the 1950s when it was reinvented by American engineers at 
> Western Electric.
>
> Peace,
> Paul
>
>