This particular recording project
started a couple of years ago when I suggested to Ian, organist for
the Bell'Arte Singers and resident organist at Knox Presbyterian Church
where A Childe Is Born (AI-CD-003) was
recorded, that we might undertake an organ project in his home church.
My idea was to do it in surround sound, having been playing with various
recording techniques to get true matrix front-to-rear separation (and
rear left-to-rear right, the major failing of Dolby Surround) without
needing the electronics of an encoder and the attendant distortion
and unwanted extra phase shifts.
I suggested to Ian that he think
about program material that was not the kind of showoff stuff that
makes it onto every other organ LP or CD, but unusual pieces that
show the coloristic capabilities of the Knox organ, and added the
audio instruction that at least some of these use the trumpets at
the rear of the church (see photo), and also have enough deep bass
pedal to maintain audiophile credibility.
I've been interested in acoustics
most of my life, and have been directly involved in surround sound
in its various historical forms for longer than I've been writing
about audio. In fact, my writing career began in 1972 when I was in
the final years of managing the Queen's University radio station CFRC-AM/FM.
Because I was doing some freelance writing and music broadcasting
for CBC and Toronto's CJRT-FM, I caught the attention of FM Guide
publisher Forbes Calder, who asked me to write about the quadraphonic
craze that was taking over
audio. The result was a column called QuadrAnswers, which grew into
regular product reviews, and by 1973 the Audio Ideas radio show on
CKFM. Next came the move to Toronto, since most of the work was there,
and more broadcasting with CBC, including a series called In The Middle
Of The Music, which was all quad recordings, including BBC transcriptions
in SQ, and lots of LPs in SQ and QS.
I had plenty of equipment to play
with and review, as now (I remember in particular monster receivers
from Sansui and Marantz). But I'd also been doing quite a bit of recording,
this increased by the provision by CBS Technology Center in the U.S.
of a Sony (they had close connections even then) SQ Encoder for matrixing
discrete tapes and discs (CD-4); incorporating 4 channels of mike
preamps, as well as line inputs, it ended up being used for a lot
of recording of SQ open reel tapes, including concerts by the Canadian
Electronic Ensemble, various choirs and organs, and numerous chamber
music ensembles. Some of this was for broadcast, some for fun, and
quite a few became LPs, though not usually identified as SQ because
by the mid-70s quad had become synonymous with corporate infighting
and acoustic distortion, killed in the market by the former, and rejected
by the high end because of the latter.
Sniffing Around Surround
As a comment on the reaction of high
end audiophiles, I was amazed at all the nose-sniffing at multiple
channels, because I had come to feel that spatial presentation was
the major failing of purist audio reproduction, and sought out better
sounding surround decoders, eventually getting from England the one
I still use, the Integrex Ambisonic/SQ/QS/Hafler decoder designed
by the Ambisonic developers, led by the late Michael Gerzon and Peter
Craven. With very precise matrix phase shifts for rear channels, and
no logic steering, it provided spatiality with limited separation,
but very low distortion.
This led me to think that it might
be possible to achieve the counterpart of this in the record process,
a fully acoustic matrix dependent only on the natural spatial acoustic
heard by the microphones from a central point and the adding/subtraction
process of the 4 signals following the mike preamps. This would result
in a naturally derived encoded surround signal that would decode with
any Hafler or similar system.
Experiments through the early 90s
resulted in what has been employed in this recording, utilizing a
pair of 90o-angled AKG 460ULS cardioid mikes facing frontward, and
a rear-facing AKG C522ENG stereo mike with identical capsules inside,
also at 90o angles, but very close together. This way the average
of the front and rear capsule spacing laterally is about the width
of a human head, and if you shot a bullet through the front capsule
right down the barrel of the microphone it would also pass right through
the rear-faced capsule of that side, either left or right. For those
familiar with coherent miking systems, this setup is quite similar
to crossed figure-of-eight, or Blumlein, with the difference that
the signal of each rear channel is maintained on its correct side,
and can therefore be properly added and subtracted with its front
channel to derive the front and rear spatial information. This is
my approach to a coherent matrix array, with the rear microphone channels
reversed in polarity (180o) at the microphone preamplifiers to provide
an in-phase centre and resultant correct phase shifts for derivation
of 4 matrix channels. These were derived at the output of the pair
of Bryston BMP-2 stereo mike preamps before Meridian 607 A/D conversion.
The result is what we call NaturalMatrix, an acoustically encoded
surround recording that will provide separate left and rear channels
on any non-DSP matrix decoding system, from Hafler to Hall mode.
Getting Into (The) Gear
Our microphone cables were generously
supplied by Kimber Kable, Ray Kimber himself an organist, and are
balanced KCAG Silver in a 50-foot 4-microphone snake. I don't think
I have to say any more than that this is the most transparent microphone
cable I've ever heard, and will be a continuing fixture with Audio
Ideas Recordings. Its resolution is extraordinary.
Having the microphones, their deployment,
preamplification, and matrixing in hand, I looked at record media
and monitoring. Having been very impressed by the PMC LB1 small professional
monitors as a Hi-Fi speaker, and especially knocked out by their deep
performance, I settled on these as monitors for playbacks, and while
Ian was performing, used my trusty Grado SR125 headphone, which also
has outstanding bass, as well as a very speaker-like tonal balance.
This left recording media to sort
out, and I considered using something like a TASCAM DA-88 to allow
later mixdown to NaturalMatrix, but rejected this on grounds of purity,
wanting the surround to be directly recorded on site. Curious about
the arguments touting even 15 IPS 2-track analog as superior to 16-bit/44.1-kHz
digital, I decided to employ my trusty old TEAC X-2000M recorder as
a backup; it had served well as an analog stage for blade-editing
A Childe Is Born, and if the sound was more than acceptable there,
then with some really good tape, it should provide a pretty good analog
recording. Given the blower noise of the organ, the noise floor was
not an issue, so its dbx noise reduction was not engaged. Tape was
Maxell 50-120B, one of the higher headroom tapes out there, and bias
was calibrated for it very precisely.
It may seem odd to use a TEAC DA-P20
DAT portable as the digital medium, but one must remember that it
was simply a recording transport, fed a high resolution digital signal
from the Meridian 607, which claims dithered resolution to below 120
dB, and is certainly the best 16-bit processor I know of. Clive Allen
and I have been experimenting with digital media for years. The Debussy
Preludes was recorded on Super VHS tape using the 607, but he had
discovered data-grade DAT tapes to be as good in resolution and freedom
from dropouts, so that's what I settled on here.
To sum up this technical part of
things, let me note that the contest between the analog and digital
tapes was brief, and not even close. The clearly audible low frequency
harmonic distortion, high frequency tizz, and midrange congestion
of the analog tape (and this was without pushing the levels) made
the choice easy, and the analog machine was left home for the subsequent
two sessions. The data grade Maxell DATs had a clarity and openness
that suggested very good data integrity and freedom from dropouts.
I had planned to add a repeat analog comparison track at the CD's
end, but Ian wasn't too keen on this for musical reasons, and I ultimately
decided that it was a question that had been already answered conclusively.
I still have an edited 15 IPS tape from the first session that sounds
very good, a little warmer and fuzzier than the digital. I also have
a CD-R master with the extra track; that disc ended up being a safety.
Editing was done in the Sonic Solutions
system (now all AES/EBU) at Clive Allen's Georgetown, Ontario studio,
and didn't take long because Ian is such a great player, and knew
the pieces very well. The majority of the tracks on the CD have no
internal edits, and most of the studio time was devoted to between-track
edits; since each work had different organ registration, the tonal
signature of the blower noise changed when going from one to the next,
and we tried, sometimes not too successfully, to blend these transitions.
You will hear these changes between tracks, especially on headphone.
The only failing of this wonderful instrument is its fairly high noise,
and our aim was to try to make it as unobtrusive as possible.
Ian's program, The Sadler Selection,
ranges widely from the more familiar, an organ transcription of Elgar's
Nimrod from the Enigma Variations, to the utter pedal power of the
Karg-Elert Pax Vobiscum and the Variations de Concert by Joseph Bonnet,
to charming theatre organ pieces by de Severac and Bourgeois. It's
about as varied as you could imagine, almost 64 minutes.
I've listened to the CD-R safety
on a wide variety of matrix systems, on CD, LD and DVD players, with
various surround processors. They don't all sound the same, but they
do sound very musical and enveloping, which is what you'd hear anywhere
in the large space of Knox. I think it's a fun disc for audiophiles,
music lovers, and, especially, for organ aficionados.