Hi Folks,
Many thanks Geoffery for your detailed reply. I probably now have even more
questiones than I started with.
I have been able to regain contact with Bob Harrison (no longer in
Broadcast), and his memories tie in with yours - I hope diaries can be
found.
You are quite right about his enthusiam (continuing) with the SFM. He has
been able to contact Steve Jagger at Calrec, who consulted the factory
records. They still have Microphone 501 in their meuseum. 502 was used by
Michael Gerzon and Peter Felgate, I hope some dates can be filled in.
Bob also sent a photo of Michael Gerzon and Peter Craven - looking very
pleased and amazed by the tetrehederal array of early SFM, photo is on
Stephen Thorntons site.
I was facinated to learn that Peter Craven empirically 'discovered' the
tetrehederal layout of the 4 capsules, (and so nearly 'discovered the much
larger Stereo Sphere mic) and Michael worked out why it sounded
so good and predictably.
Best Regards
Steve Higgs
Message: 1
Date: Wed, 09 Feb 2011 10:58:21 +0000
From: Geoffrey Barton <[email protected]>
Subject: Re: [Sursound] Calrec CM4050 Surround Microphone SN: 502 -
update
To: [email protected]
Message-ID: <[email protected]>
Content-Type: text/plain; CHARSET=US-ASCII
Message: 1
Date: Thu, 3 Feb 2011 11:59:36 -0000
From: "Steve Higgs" <[email protected]>
Subject: Re: [Sursound] Calrec CM4050 Surround Microphone SN: 502 -
update
To: <[email protected]>
Message-ID: <005b01cbc399$d92b3050$0200a8c0@OFFICE>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=original
Dear Iluminati
An rathey practical posting and update as to my investigations into this
mic, - it does work, with only a slight modification as to a safe chassis
earth to the mains PSU.
Some more clarification as to its construction. The mic head appears to
be
just as it left the factory,
The head cable is remade - now 10meters .
The mains PSU is tested and working, it does contain 4 FET/transistor
amplifiers - or is that filters. A set of tweaks inside (with
amps/filters
on a Vero board construction and another 4 multi-turn tweaks accessible
from
external. So provision for fine tuning - set-up. The polarising voltage
measures 52V off load.
The pair of joined diecast boxes are untested. A mains cable is provided
to
the bottom box marked 'amplifiers', which also has mono jack inputs for
the
signals from the above filter?/PSU.
The top box with I believe PBF's notes written on masking tape contain 2
Vero boards mounted on edge connectors, the bottom board has 4 daughter
boards with 2 x 8 pin OP amps, the top board has no components - just
some
wire links (a simple programmer?).
No passive processing.
My investigations lead me to Richard Elen's article 'Ambisonics - a BBC
Soundfield Experiance', from Studio Sound/Sound International from Oct
1979,
just 3 years after I joined the BBC. Paragraph 14 is when I started to
see
daylight. Antony Askew is I'm afraid no longer with us, an I am at the
moment out of contact with Bob Harrison. I strongly suspect that this mic
and collection of boxes is the prototype MK2 evaluated at the RAH at the
Proms in 1979. Jeff Barton might you remember?
Steve,
I think that in 1979 it was a MKIII. As I recall it was John Rushby Smith
in command, so you might try asking him if he is still around.
I was there at several of the broadcasts, mainly providing moral as well
as technical support to Bob Harrison, who on a number of these occasions
put his job on the line in his advocacy for the SFM and Ambisonics.
1978 was probably a MKII, but I will have to dig out my old diaries to
check.
As other readers of this list
I am very interested as to what was the (if any) processing provided for
the
MK1, why did Reading University at some time and trouble construct this
control/processing kit, and what was the post microphone processing kit
supplied (factory) with a MK2.
No factory processing was supplied for a MKII, the first control box was
for the MKIII.
That is why we built our own.
The MKI and MKII were part of a research project at the university; we
were making it up as we went along, so there was no 'factory' processing
available.
It is amazing how things 'come around. I have been closely connected with
the surround mic set-up at the proms for HD TV for the last 6-7 years to
provide the required 5.1 output - Just the TV output, while all mics are
available to both Radio and TV the surround TV (BBC2) output is mixed
entirely separately to the Radio output. Unfortunately a Soundfield is
not
used. A MK5 was again evaluated during the 2009 season and was not found
to
be satisfactory. Any microphone has got to be 'in the right place' and
remote control of it's parameters cannot totally make up for positioning
for
the highest quality recordings, (I'm sure this can be argued, especially
with the very recent advent of digitally processed microphones such as
the
Schoeps Super CMIT). The RAH is a very - well unique if not difficult
place
to record, and perform as a soloist, essentially a lack of early
reflections - and then the echo.
Absolutely. If you stand centre stage at the RAH and just make a single
handclap you can hear all the problems.
I think the particular problem with recording with the SFM there is that,
if you put it in the normal 'stereo' position, behind and above the
conductor, the recording sounds like you are floating in space, especially
played back periphonically, this is partly because of the lack of early
(floor!) reflections. Musically it balances ok, apart from perhaps too
much brass. But then, that often happens....
rgds,
Geoffrey
End of Sursound Digest, Vol 31, Issue 5
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