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"Hz vs Church" aims to use Churches
[or other big sized public buildings] as post loudspeakers in
order to create, unfold and play live various sounds which appear
in the "aural surface" by using and manipulating in
real time, different kinds of frequencies. The frequencies and
sounds have been created by using tone generators. This project
builds on the phenomenon of resonance [Hermann von Helmholtz],
when one of the core ideas, is to use the pure sounds in a way
that Pierre Schaeffer described as objects sonores [musical objects].
This, enables the audience to re-decode, perceive and redefine
music by listening profoundly to some elements that obviously
appear in numerous audio outputs, but not individually and instantaneously
like in "Hz vs Church". Some of the sounds are amplified
ultrasound and infrasound frequencies. I also use various kinds
of noise such as white, pink, brown and blue noise.
The main part of the performance
consists of frequencies from 40-12000 Hz. Triangle, sawtooth,
square and sinewave tone generators have been used to create them.
Most of the sounds will be played in the same volume level, and
this is because I would like to enforce the room to show up its
own voice. One of my goals is to outline the diversity between
the sounds. As the layers of its frequency are getting denser,
a drone with various overtones is making reflecting sounds into
the building. There are three types of reflections that people
hear in a church or in an auditorium. Early reflections, late
reflections and reverberation. My effort is to work with the early
reflections of the sound trying to establish and build up an intense
sonic environment both in the meaning of the sound itself, and
additionally, in how the sound is being amplified when played
inside such a reverberant space like a church or a cathedral.
The sound works in an indirect way inside churches, cathedrals
or auditoriums. The loudspeakers illuminate the entire view of
the room/hall but only a tiny fraction 1/5th of 1% of the sound
actually hits the target [the human ears in performance situation],
the "direct sound".
"Direct sound" refers
to the notion of trying to create field of sounds which spread
less than most traditional loudspeakers. One method of creating
directivity utilizes very large arrays of loudspeakers, all driven
together in-phase. This creates a very large source size compared
to wavelength, and the resulting sound field is narrowed. The
rest of the sound, over 99.8% of it, the "indirect sound",
misses the ears continuing on, crashing into the walls, floor,
the people, chairs, the roof and its beams, the walls, windows
and doors. Every time some part of the indirect sound hits a surface,
it is reflected. How the surfaces of the hall reflect the indirect
sound determines how the room sounds, its voice. And this is also
depending on the material that has been used to construct the
interior building surface. It is important to mention that, in
all wave producing sources, the directivity of any beam, at maximum,
corresponds to the size of the source compared to the wavelengths
it is generating. The larger the source is compared to the wavelength
of the sound waves, the more directional beam results. Sound waves
have dimensions of inches to many feet, which is approximately
the size of most loudspeaker systems. At high frequencies, however,
the wavelengths are quite short, which can result in a narrow
distribution of sound from the tweeters in a conventional loudspeaker
system. What happens to the reflections of the indirect sound
is the challenge for me here and it is what I would like to be
focused on.
I want to use the building as a
post-loudspeaker. The amount of indirect sound that is reflected
depends on the acoustic nature of the reflecting surface. The
indirect sound remains in the hall reflecting off of one surface
after another, remaining audible to the listeners until it finally
disappears, having been absorbed and leaked out of the room. There
are two ways to make sound "louder". The ordinary way
is to make it physically louder. Not all reflections help hearing
but those that do help people understand what they are hearing
are called early reflections. Adding early reflections raises
the apparent loudness of the direct sound in a comfortable, natural
way, much more agreeable than turning up the volume. On the other
hand, a good example of a late reflection is echo because it is
a reflection that can be distinguished as being separate from
the direct signal.
In "Hz vs Church" I would
like to avoid dealing up with late reflections. The main reason
is that my effort is to create an intense sonic environment in
which the rapid cut-ups and the sudden changes in between the
sounds are "cornerstones" in what I call "intensity".
Both in mental and listening procedure. In time speaking terms
the cut-ups between the different sounds will happen at the very
exact moment when I feel that the sound is getting deeper, at
the very exact moment when layers are obviously getting denser
and the hall is acoustically "filled up" and begin presenting
its own "voice". When I feel that the audience is ready
to dive into the phenomena and spaces of sonic interest, when
the time warns me up on this, then I cut it up and rapidly put
the next sound. No fade ins, no fade outs. Just cut-ups.
Reverberation is a very common thing
in big rooms or places like churches. Reverberation is not a series
of echoes, like late reflections are. It is much more chaotic
than that. Reverberation can come from somewhere but it is an
overflow of chaotic sound being stored in a reverberant space.
It is not a reflection of a sound wave. Reverberation is the proper
term, when so many reflections arrive at a listener that he is
unable to distinguish between them. Sabine's reverberation equation
was developed in the late 1890s in an empirical fashion. He established
a relationship between the RT60 of a room, its volume, and its
total absorption [in sabins]. This is given by the equation:
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where c is a mathematical constant
measuring 0.161, V is the volume of the room in m3, S total surface
area of room in m2, a is the average absorption coefficient of
room surfaces, and Sa is the total adsorption in sabins. The total
absorption in sabins [ and hence reverberation time ] generally
changes depending on frequency [dependent on the which is defined
by the acoustic properties of the space], and that the equation
does not take into account room shape or dimensions, nor losses
from the sound travelling through the air [important in big spaces
like Cathedrals]. Generally, most rooms absorb less in the lower
frequencies, causing a longer decay time.
In "Hz vs Church" the absorption, the
decay time and the reverberation will change dramatically and
rapidly between the different sounds and frequencies.
The reverberation time RT60 and the volume V
of the room have great influence on the critical distance dc [conditional
equation]:
By using these different sounds and frequencies
I want to generate a unique loudness for the direct sound and
then compliment this with a bevy of early reflections, immediately
followed by a distinct absence of late reflections and finally
backfilled with a groundswell of distant sounding reverberation.
The whole attempt is to present an exercise for the ears, to test
the limit of the sound-gates in a room like a church and to figure
out audience's resistance, time-wise and listen-wise. We perceive
a place with the ear and the eye. The eye perceives mainly material,
when the ear perceives in a more conscious and concrete way.
"Hz vs Church" is not about mucical
pleasure. The focus is on sound as an event and the explicit translation
of sound in physical terms. It is about provoking new modes of
perceiving and experiencing one's own body and hearing by triggering
variable and autonomous psycho-physiological responses. The major
target is to create a multitude of effects in the audience, starting
from high frequencies extreme mental intensity, and lead to the
body's great sway that low frequencies produce.
"Hz vs Church" is about the total acoustic
sense of space, observing sound to control and measure the aural
capacity of architecture by using material which, precisely, can
be described as "audio assault".
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