Handbook for Sound Engineers

Microphones 553

16.7.7.3 Holophone H4 SuperMINI Surround Sound
System

The H4 SuperMINI head, Fig. 16-134 contains six
microphone elements, that translate to the standard
surround sound loudspeaker configuration; L, R, C,
LFE, LS, RS. The LFE collects low-frequency signals
for the subwoofer. The six discrete channels are fed into
a Dolby® Pro-Logic II encoder which outputs the audio
as a stereo signal from a stereo mini-plug to dual XLRs,
dual RCAs, or dual mini-plugs. The left and right stereo
signals can then be connected to the stereo audio inputs
of a video camera or stereo recorder. The encoded
signal is recorded onto the media in the camera or
recorder and the captured audio can be played back in
full 5.1-channel surround over any Dolby® Pro Logic
II–equipped home theatre system.The material can be
edited and the audio can be decoded via a Dolby® Pro
Logic II Decoder and then brought into an NLE
including Final Cut or iMovie, etc. The stereo recording
can also be broadcast directly through the standard
infrastructure. Once it is received by a home theatre
system, containing a Dolby® Pro-Logic II or any
compatible decoder, the six channels are completely
unfolded to their original state. Where no home theatre
receiver is detected, the signal will simply be heard in
stereo. The SuperMINI has additional capabilities that
include an input for an external, center-channel-placed
shotgun or lavalier microphone to enhance sonic oppor-
tunity options and features an audio zoom button that
increases the forward bias of the pickup pattern. It also
includes virtual surround monitoring via headphones for
real-time on-camera 3D audio monitoring of the
surround field.

16.8 Microphones for Binaural Recording

16.8.1 Artificial Head Systems

Human hearing is capable of selecting single sounds

from a mixture of sounds while suppressing the

unwanted components (the cocktail party effect). This is

done in the listener’s brain by exploiting the ear signals

as two spatially separated sound receivers in a process

frequently referred to as binaural signal processing. A

simple test will verify this statement: when listening to

a recording of several simultaneous sound events

recorded by a single microphone, the individual sources

cannot be differentiated.

Two spaced microphones or more elegant multiele-

ment spatially sensitive microphones, such as a stereo

coincident microphone, have been used to capture the

spatial characteristics of sounds, but they have

frequently been deficient when compared to what a

person perceives in the same environment. This lack of

realism is attributed to absence of the spectrum modifi-

cation inherent in sound propagation around a person’s

head and torso and in the external ear—i.e., the transfer

function of the human and the fact that the signals are

kept separate until very late in the human analysis chain.

The acoustic transfer function of the human external

ear is uniquely related to human body geometry. It is

composed of four parts that can be modeled mathemati-

Figure 16-133. Location of the microphones on the
H2-PRO head. Courtesy Holophone®.

Center rear

Left and right surround

Overhead (top of head)

Low frequencies

(inside of head)

Left and right

Center

Front of microphone

Figure 16-134. Holophone H4 SUPERmini Surround

SSound System. Courtesy Holophone®.