The Helmholtz
resonator is a device to control
resonance is very well known
It consists of a volume of air
enclosed in a cavity, coupled with
the outside through an opening to
form a mechanical system of the type
mass-spring with its own resonance
frequency, at which the system is in
able to absorb a considerable part
of energy.
The absorption of a resonator of
this type is very selective about
the frequency of resonance and
particularly effective in the case
of low-frequency tones.
However, a resonator is not only
to absorb.
The principle of the resonator
was used already in antiquity to
increase the volume of the voice
actors in the theatre air and
amplify the vibration of the strings
of instruments like guitar, violin
and other strings.
The resonator has so far found
little application in domestic
environments suitable to reproduce
music.
The reason is very simple.
To develop a resonant device
effective to combat the specific
acoustic problems of a very specific
environment should be a precise
instrument, such that the device is
really effective in dealing with the
critical frequency of that
'environment without affecting the
others. Resonator works in a narrow
band and broadband, such as the
DAADs work.
A resonator is therefore a system
stiff, fixed and built to a very
specific environment. It has to be
well calculated, by having to
interface between the environment
and the speakers. This is important
if you do not want to cause a
acoustic disaster.
Despite the potential of the device,
it has been up to now very difficult
to use in the home environment and
thus has been little used.
Polyphemus is the modern application
of the principle of Helmholtz making
it possible use this feature free of
usual problems and have effective
use of the resonator in the home
environment and many more positive
side effects.
Polyphemus can be adapted to any
acoustic environment issues or
problems.
Through some substantial technical
change its resonance frequency
accorded to that required in a
certain environment.
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Its possibilities are almost
limitless
Starting at 26 Hz, Polifemo gives
the opportunity to work on any
frequencies in a clean and
well-defined way.
Changing the environment or
replacing the speakers may not be
nessesary. Polifemo may be employed
to fully exploit the potential and
the lost potential of an existing
system.
Polyphemus has a cylindrical
shape
At the base, which is appropriately
elevated from the ground, two holes
of different diameters that can be
opened or closed, individually, to
achieve different combinations of
intervention.
A half cylinder there is the "eye"
of Polyphemus, a sophisticated iris
diaphragm, whose aperture can be
changed seamlessly.
The arrangement of the openings
of the device is not random
Since it can be considered as a
speaker, the orientation of the 'eye',
which is obtained by rotating the
entire device, influences the
distribution of the sound
environment, address as more
convenient in terms of
representation of space , tone,
dynamics of the reproduced sound.
Inside the cylinder there is a
further possibility of adjustment: a
swinging sound-absorbing membrane
changes timing and the velocity of
the air flow inside. Also this
changes the response of the system
to adapt to the needs of listening.
All these possibilities of
Polyphemus can be managed by
instrumental and / or by the senses.
The results are striking to the ear
and during the instrumental analysis
phases.
In addition to the precise control
and articulation of bass frequencies,
the result is that Polifemo creates
a clear enlargement of the space as
a result of better resolution at the
low frequencies, and an improvement
of how the medium and high
frequencies "float" on the low.
When the system is properly tuned,
Polifemo is at it's most striking in
terms of dynamics, which is enhanced
by realism, gaining in terms of
micro-information.
In one household room of a
traditional size one or two may be
needed. These can be tuned in a
different ways to correct asymmetry
of the soundstage and to solve
various problems. In some cases, to
obtain the best results 3 or 4 can
be used.
Generally these must be arranged in
the corners or the middle of the
walls and
can be used with other acoustic
treatment systems such as DAAD or
Eco DAAD.
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