Recording - April 2017 - 8

TalkBack
Wider than wide?
Hello Eric Ferguson: Thank you very much for your multipart Phase Primer series (December 2016-February 2017). I
now understand the concept, probably for the first time! I have a
question that relates to phase, although it has other implications.
I am often asked to record conservatory classical music
students for festival and grad school auditions. They need audio
and video, and I have to travel light, so I use small-size audio gear
that I can mount on the camcorder tripod stand: a pair of Schoeps
CMC6 MK4 mics feed into a Sound Devices USBPre 2 preamp/
converter unit, and its S/PDIF digital out goes into the digital input
of a TASCAM DR-100 MkII for the digital audio capture.
The mics are in ORTF, 17 cm apart and at the standard
110-degree angle. I currently just use the resulting stereo WAV
file. But I am wondering whether I should get two mono tracks
and pan them to get more separation than the natural
separation that arises with the ORTF pattern.
I am normally about 10' away from the musicians as this
allows the mixture of sounds to blend with the room acoustics,
giving a natural "live concert" result. Would there be an
advantage to outputting two separate mic tracks for post-record
panning in order to avoid possible phase issues? Or if phase is
not an issue with ORTF, would it still be advantageous to pan
the tracks to widen the stereo image?
Steve Harrow
Honeoye Falls, NY
Eric Ferguson replies:
Hi Steve: Thanks for appreciating the phase articles!
As far as I can tell from your description, your Schoeps mics are
in ORTF and are recorded discretely to a stereo WAV file. They
are therefore already panned as wide as possible, at least in the
original recording. If you split the tracks in a DAW or console, you
would not be able to pan them wider. Put on a pair of headphones
and listen to the two mics panned hard L/R and you will hear what
each mic hears in the corresponding ear, no more, no less.
If you want a wider stereo image, you would have to start at the mics
themselves, by moving the mics farther apart, and therefore no longer be
in ORTF. This would provide greater imaging and depth, but would result
in more phase issues when the recording was played back in mono.
Is this a problem? Not necessarily. While I have used ORTF to
record many a classical recital, I have no fear in spreading mics
outward to achieve greater depth at the expense of mono
compatibility. This is exactly what spaced overheads and piano
mics achieve. Wide, pop music stereo imaging is partially created
by mic pairs receiving significantly out-of-phase information.
Personally I think ORTF presents a nice compromise between
spaced mics and coincident mic techniques such as X/Y. The

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attractiveness of ORTF is that the mics are slightly more separated
compared to X/Y, Mid/Side, and Blumlein. This grants a greater
phase difference, which widens the image.
X/Y is theoretically more mono-compatible, with fewer phase
issues when the two channels are combined, but in my experience I
often take extra width over slightly lessened mono compatibility. ORTF
mics are still quite close, and the resultant comb filter that occurs
if the two mics are mixed in mono should only affect seriously
off-axis sources, and only in the high frequencies.
The bottom line: experiment and do what you think sounds
good! But if you choose to spread the mics out farther then
ORTF, you might want to monitor the recording in mono before
committing to make sure the resultant combing doesn't sound
bad to your ears. A small mixer or monitor controller could give
you this ability. Good luck!-EF

Choosing a high-end dynamic mic
Hi Paul Stamler: Would you mind giving me a bit of mic advice?
I teach sax, flute, and clarinet in an inadequately treated room. I
have many high-end condenser mics in my recording studio, but
I'm moving away from using them in my teaching studio because
the room isn't helping the recordings I make for my students. Since
I'm installing a new high-end interface, I felt a mic adjustment
was in order, and moving to a dynamic cardioid or supercardioid
seems like a good way to knock down the room's influence.
My interest lies in the Electro-Voice RE20 and the Sennheiser
MD441 because of their uniquely flat response in the dynamic
world. But because their designs are so different, I figured there must
be significant differences in their sounds. Can you help me choose
between the two for alto/tenor sax, clarinet, and flute? Thank you!
Keith Felch
keithfelch.com

Paul Stamler replies:
Keith, that's a complex question-probably the best answer is
to find a dealer that will sell you one of each to try out in your
room, then let you return the one you like less. There'll probably be a
re-stocking fee, which is fair. That said, my (limited) experience with
the MD441 tells me that it's less colored than the RE20, which has
a hefty presence boost.
However, you described your teaching room as "inadequately
treated". Additional acoustic treatment would probably improve
your recordings more than a new mic!
It's also worth knowing that the majority of a wind instrument's
sound comes from the highest open hole, not from the bell.
Miking the fingerboard up near the top is a better strategy than
miking the bell. Peace-PJS

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RECORDING April 2017

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