Tom et al
Very interesting posting, revealing some of the procedures and reasonings behind Mercury's mike set-ups. I think some companies used two spaced omni pick-ups, (if I recall correctly, Capitol Records had an inner sleeve with their stereo LPs describing a stereo procedure using 2 mikes), but the 3 mike system makes infinitely more sense. As I think I've posted before, I used a modification of the Mercury set up for my orchestral recordings - there were 3 omni mikes across the front of the stage but the centre one was actually the mid portion of a C24 mid-side configuration. The side mikes were C12s whenever they were available - the C 12 being a mono version of the C24.
I wouldn't say that Blumlein "invented" the 45/45 cutting method, I think he just put it forth as a possible way of cutting a single groove stereo record. I don't know what, if anything, Blumlein actually issued a patent for. Actually, since he was working for EMI, it's quite possible that all of his developments were the property of that company and not his personally. Since it would be fairly difficult to build a 45/45 cutter, I imagine that his experimental stereo discs were likely cut using two separate recording heads - one starting at the edge of a disc and the other starting about 3 inches closer to the centre.
On Saturday, August 30, 2014 2:08:40 PM, Tom Fine <[log in to unmask]> wrote:
>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
>-- 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.