Recording - November 2014 - 17

And that's why DPA has such excellent
omni behaviour from its subminiature
diaphragms that it uses in its smaller
microphones?
Correct. That is actually perfectly omni
all the way up to 20 kHz.
Now, when we were at the clinic in
Copenhagen, we did two tests.
Yes. In the first test, we had a voiceover
announcer in our isolated studio, and we
equipped her with a lot of different vocal
microphones. She wore several versions of
the DPA miniature capsule-an omni headset, a cardioid headset, a clip-on lavalier
mic on her blouse, and the new d:screet
necklace-mounted mic. And then, as a control, she also had a table-mounted microphone using the standard DPA mediumdiaphragm 4018 supercardioid capsule.
We had her read a news story and we
compared the sounds of the different mics,
first in a quiet studio and then with a speaker playing back pink noise behind her.
Let's talk about the different types of
mics that we had, omni versus directional and the larger-diaphragm table
microphone at a longer distance versus
the smaller microphones. This is not
dissimilar to someone singing on a
stage or in the studio with a band,
where the instruments may or may not

be isolated behind gobos. What sort of
behaviour should we expect with an
omni vs. a directional mic in this case?
I'd say if you're able to control the
acoustics, as we of course were in our studio, then you can use more open directionalities like omni or wide cardioid, way more

Figure 1. This chart, provided by DPA
Microphones, shows the polar pattern of the
4099V instrument microphone as a function
of frequency. Note how all but the very lowest (black) and highest (yellow) curves match
closely from 0º (the front of the mic) to 90º
on either side. This is similar to the behavior
of the 4011 mic discussed in the interview.

often than you probably expect. It's always
been a puzzle to me why so many engineers
prefer a cardioid microphone. I personally
prefer the omni if it's possible to use it; I
always recommend starting with an omni
and only going for a cardioid if you need
more isolation. Whenever you go for a cardioid, you should also be aware of proximity effect issues, handling noise issues, more
pop noise, and you have to suspend the
microphone or put up foam to protect it... all
of these matters are due to design. The
diaphragm on any pressure gradient microphone needs to be softer, because it needs to
react to small pressure differences between
the front and the rear side of the diaphragm.
So it's actually in the details of the
design of the mic itself that makes it so
much more sensitive to an environmental effect. A reader who's learning to do
this needs to balance the possibly
pleasing tonality of a directional mic
against the fact that they are more
temperamental to use under certain circumstances.
At least that's something you need to be
aware of.
This is something which I don't think
anyone ever thinks about, but which
DPA has done a lot of research on,
based on our chat at the time...

http://www.primacoustic.com http://www.primacoustic.com/hearthedifference

Recording - November 2014

Table of Contents for the Digital Edition of Recording - November 2014