General Product Description
The EVX-180B low-frequency transducer is designed for professional sound reinforcement or studio monitoring applications that require maximum output with low distortion.
The EVX-180B woofer provides unprecedented power capacity, linearity and excursion, made possible by the HeatWick® total-thermal-engineering design. The proprietary HeatWick design actually “wicks” heat away from the voice coil, significantly increasing power handling and long-term reliability. A special frame extension and elongated pole piece provide a metal surface with close proximity to the entire length of the voice coil, providing a major heat-transfer path. Also, the 100-mm (4-in.) diameter voice coil is longer than conventional medium efficiency woofers to give additional power handling and virtually eliminate dynamic-range power compression.
Additionally, a Flux Demodulation Device (FDD™) reduces distortion in the critical mid-band by providing a “short circuit” effect to prevent amplifier-signal modulation of the static magnetic field.
A ribbed, Kevlar® fiber composite cone with an extremely high stiffness-to-weight ratio and exceptional strength gives the EVX-180B increased resistance to cone collapse and deformation, without sacrificing efficiency.
Architects’ and Engineers’ Specifications
The low-frequency transducer shall have a nominal diameter of 460
mm(18 in.), overall depth not greater than 198 mm (7.92 in.), and weigh no more than 11 kg (25 lb).The frame shall be made of die-cast aluminum to resist deformation. The magnetic assembly shall have an extended pole piece to reduce inductive variances with excursion, and provide a symmetrical magnetic field at the voice-coil gap. Two aluminum rings shall encircle the pole piece above and below the magnetic gap, and shall have internal diameters concentric with the internal diameter of the steel top plate. The upper ring shall be part of the loudspeaker frame. Both rings act to reduce flux modulation and provide a heat transfer path from the outer diameter of the voice coil.
The voice coil shall be 100 mm (4 in.) in diameter and 20 mm (0.8 in.) in winding length, and shall be made of edge-wound aluminum ribbon. When centered in the magnetic gap, the voice coil shall produce a force of not less than 21.9 newtons (tesla-ampere-meters) with a dc current of 1 ampere. Performance specifications of a typical production unit shall be as follows: measured sensitivity (SPL at 1 m (3.3 ft) with 1-watt input, 100 to 800 Hz pink noise) shall be at least 96 dB. The half-space reference efficiency shall be at least 3.0%. The usable frequency response shall be 20 Hz to 2,000 Hz, and the nominal impedance shall be 8 ohms. The rated power for the loudspeaker shall be 1,000 watts continuous power.
The low-frequency transducer shall be the Electro- Voice® EVX-180B.
Directional Characteristics
The directional characteristics of the EVX-180B in the TL3512 256-liter (9-ft³) vented enclosure were measured by running a set of polar responses in EV’s large anechoic chamber. The test signal was octave-band-limited pseudo-random pink noise centered at the ISO standard frequencies.
EVX-180B
18 Inch Low-Frequency
Reproducer
The curves show horizontal (side-to-side) dispersion when the enclosure’s long axis is vertical. The vertical (up-and-down) polar responses deviate only slightly from the horizontal responses due to box geometry.Typical data is provided in Figures 1 and 2, which indicate 6-dB-down beamwidth versus frequency and directivity factor, respectively, for an EVX-180B in the TL3512 enclosure.
Electrical Connections
The EVX-180B is fitted with a pair of chrome-plated, frame-mounted connectors with color-coded ends. Electrical connection is made by pushing down, inserting wire completely through the rectangular slot and releasing pressure. One conductor of #9 AWG stranded, #8 AWG solid, a pair of twisted #15 AWG stranded or a pair of #14 AWG solid conductors will fit. A positive electrical signal applied to the red (+) terminal will displace the cone away from the magnet, thus producing a positive acoustic pressure.
Recommended Enclosures
The most extended bass, lowest distortion and best control is usually realized in properly designed vented enclosures. In such designs, the vent, or port, actually provides the lowest octave of output. The vent is driven to full acoustic output by a relatively small motion of the speaker cone itself, acting through the air contained within the enclosure. The excursion of the EVX-180B at these frequencies is much reduced compared to sealed or open-back enclosures, directly reducing harmonic distortion and the possibility of speaker “bottoming.”The maximum output is limited by either: (1) the long-term thermal power-handling capacity or (2) the speaker’s maximum cone-excursion capability, whichever occurs first.-excursion capability, whichever occurs first.
Figure 1. Beamwidth vs. Frequency
