Ecler EPC200 Manual De Instrucciones página 5

THREE-WAY SYSTEMS: THE PERFECT SOLUTION
This is the optimal system to achieve faithful voice and music reproduction. It's a fact
that the human ear is more sensible in the central portion of the audible spectrum, which
enables us to easily recognize any kind of irregularity in this frequency range. This justifies the
need for a dedicated driver for the reproduction of the human voice, which ranges from 200 to
1500 Hz).
The overall structure of the EPC systems is based on two cabinets: The first one only
reproduces the lowest frequencies below 150 Hz, while the second one reproduces both the
midrange (from 150 Hz to 1500 Hz) and the high frequencies (from 1500 Hz to 22 kHz).
HYBRID BASS-REFLEX-TYPE CABINETS
This groundbreaking enclosure is the result of combining conventional bass-reflex
philosophy and a diffusion system half the way between direct radiation and a folded horn
structure.
The massive excursion subbass speakers must suffer bring up important distortion. This
distortion is caused by the fact that the voice coils often move far away from their rest
position. Thus, the magnetic flux density gets reduced. The bass cabinets in the EPC 6000
system use two electrically phase-inverted parallel mounted 18'' drivers. One driver is mounted
in opposite direction. With this configuration, when the voice coil of the first driver moves
forward, the second voice coil moves backwards, resulting in a remarkable cancellation of
second-order harmonic distortion and a slight cancellation of third-order distortion. A very clean
sound and an excellent "cone control" are consequently obtained even in critical situations. It
has to be considered that conventional subwoofers at high output levels may reach up to 10 %
distortion.
Each loudspeaker is mounted into a separate acoustic enclosure, including a dedicated
port. This reminds "transmission line" systems. The angled position of the drivers and the
separation wall share similarities with folded horn-loaded systems. The implemented solution is
in fact a bass-reflex concept with a certain port Q value in the way between pure direct
radiation and horn radiation, using the advantage of both worlds.
The bass-reflex system inverts the phase of sound radiated from the rear of the speaker
in order to widen the low-range playback boundary. The accurate calculation of the bass-reflex
port dimensions is a key factor when evaluating the success of an acoustic enclosure design.
ECLERs Research Department has created SIMBOX, a software based on W. Marshall Leach's
publications. It converts the different physical loudspeaker and enclosure parameters into
discreet R-L-C elements and controlled sources. The software then communicates via macros
with an electronic simulation package, which performs all calculations and facilitates graphical
representation.
Both 18'' drivers mounted on the EPC218D feature a huge permanent ceramic magnet
and 114 mm voice coils. They are able to withstand excursions up to 20 mm and 1600 Wrms
input power.
5