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SoundTube - SM31-EZ - 3" Surface Mount Speaker (Single)

SoundTube - SM31-EZ - 3" Surface Mount Speaker (Single)

The SM31-EZ features one 3 inch (76.1 mm) polypropylene driver with butyl rubber surround. It also includes weatherized components for indoor/outdoor applications. Additional, it has a theft- and corrosion-resistant mounting mechanism with an indexed swivel-joint for precision aiming in any direction. The ultra-low profile ZeroReflection™ ABS enclosure (4 inch diameter by 3.5 inch deep, including mounting plate) is corrosion-resistant with a powder-coated aluminum grille and is UL 1480 (UEAY) approved.

The SM31-EZ(-T) is a premium full-range 3 inch surface-mount speaker, with overall dimensions smaller than a 4 inch sphere. The SM31-EZ(-T) incorporates a proprietary attachment with indexed swivel-joint for complete hemispherical aiming. Components have been weatherized for indoor/outdoor applications. The SM31-EZ is an 8 ohm speaker without transformer. The SM31-EZ-T is shipped with the AC-SM31-XFMR transformer module to add a 20W transformer and 5 position tap switch that mounts into a single-gang deep junction box.

Engineered for rapid installation and low profile mounting for smaller venues, the SM31-EZ(-T) is ideal for retail, restaurants, conference rooms, patio areas, educational facilities or any setting where full-range intelligibility, unobtrusive design and installation ease are paramount. For additional bass response down to 41 Hz (- 10 dB), the SM1001p powered 10-inch subwoofer may be incorporated.

SoundTube Entertainment and the MSE Audio Group constantly develop new technologies which enhance audio product performance. SoundTube Entertainment innovations are protected by multiple U.S. and international patents, which explicitly cover SoundTube dome, enclosure and dispersion technologies. The MSE Audio Group actively defends its patents in order to protect SoundTube resellers and end-users.

SoundTube Entertainment strives to provide complete and effective technical information and data to dealers, engineers and designers. All data are available from SoundTube Entertainment or at Technical data and downloads include: EASE™ data – 3-D polar plots. EASE™ Address – 2-D modeling for distributed systems Autodesk® Revit® software Tech Sheets – Technical information and architectural specs for system engineers SoundTubeSPEC™ – Proprietary speaker placement software.

All data for SoundTube speakers are independently collected from and verified by NWAA Labs (www.nwaalabs. com) using their proprietary MACH testing system. All data are collected and analyzed according to ASTM, ISO and AES standards using EASERA, TEF and MLSSA. Full balloon data including both phase and magnitude is compiled into a variety of formats including EASE 4.x, GLL and CLF.

The loudspeaker transducer shall consist of one full-range 76.2 mm (3.0 in.) polypropylene cone with butyl rubber surround. The low-frequency voice coil diameter shall be 19.0 mm (0.75 in.). Performance specifications for a typical production unit shall be as follows: Useable frequency response shall extend from 120 Hz – 22 kHz (- 10 dB). Measured sensitivity (2.83 volt input, 1 meter) shall be at least 85.0 dB. The speaker shall have a nominal impedance of 8 ohms, with an optional 10-watt transformer (AC-SM31- XFMR) for distributed systems.

The optional transformer shall have a five-position tap switch for 25-, 70.7- and 100-volt applications. Rated power capacity shall be at least 20 watts continuous (RMS) and conform to EIA-426-B. Maximum continuous power output at 1 meter shall be 98.0 dB. Surface-mount installation for the unit is designed to mount to wall, ceiling or other rigid structure. When the optional 20-watt transformer is incorporated, mounting shall be to a single-gang deep junction box.

Vertical and horizontal pivoting shall be employed to offer unlimited aiming capability for indoor and outdoor applications. Installation for the speaker shall be by proprietary and corrosion-resistant ball mount with an indexed swiveljoint for precision aiming. External wiring shall be by low-profile screw terminal and shall accept from 10 – 22-gauge wire. The system shall be for indoor/outdoor applications. The enclosure shall be constructed of injection-molded, ABS.

The grille shall be constructed of powder-coated aluminum for lasting performance and affix to the speaker baffle via pressure fit. Overall cabinet dimensions shall be no more than 110.4 mm (4.35 in.) in height by 110.4 mm (4.35 in.) in width by 96.9 mm (3.81 in.) in depth including the mounting bracket. The system shall be the SM31-EZ for low-impedance applications or the SM31- EZ-T for high-impedance applications.


  • Two models are available, the SM31-EZ and the SM31-EZ-T.
  • The latter includes a 10-watt transformer.
  • One 3 inch (76.1 mm) polypropylene driver with butyl rubber surround
  • Weatherized components for indoor/outdoor applications
  • Theft- and corrosion-resistant mounting mechanism with an indexed swivel-joint for precision aiming in any direction.
  • Ultra-low profile ZeroReflection™ ABS enclosure (4 inch diameter by 3.5 inch deep, including mounting plate).
  • Five position selectable tap switch (SM31- EZ-T only)
  • Corrosion-resistant, powder-coated aluminum grille
  • UL 1480 (UEAY) approved
  • High quality black or white paint finish
  • Optional accessories: the SM31-EZ-T includes a 10-watt transformer (AC31-XFMR) that incorporates a 5 position tap switch and a wall plate for installation in a single-gang deep junction box. This transformer kit is also available as an optional accessory.


Product SM52-EZ - 5.25" Surface Mount Speaker (Single)
System Type 3 inch full-range, surface-mount, 8 ohm with optional 10-watt transformer for 25/70.7/100-volt applications
Impedance (Nominal) 1 8 ohm
Sensitivity dB @ 2.83V / 1 M 85.0 dB
Sensitivity dB @ 1 W/1 M 2 85.0 dB
Frequency Response (-3 dB)3 170 Hz - 14 kHz
Frequency Response (-10 dB) 3 120 Hz - 22 kHz
Max. Program Power 4 40 W
Max. Continuous Power RMS5 20 W
Max. SPL dB @ 1 M RMS 6 98.0 dB
Coverage Angle (-6 dB @ 2 kHz) 70°
Coverage Angle (-6 dB @ 10 kHz) 45°
Coverage Angle (Avg. 2 to 10 kHz) 80°
Aiming Angle 0 to 90° vertical 0 to 359° axial (full hemisphere)
Directivity Factor (Q) 4.9 (averaged 100Hz - 10kHz), 7.1 (2kHz)
Directivity Index (DI) 5.1 (averaged 100Hz - 10kHz), 8.5 (2kHz)
Tap Selector Five--position tap switch (transformer accessory only)
Low-Frequency Driver 19.0 mm (0.75 in.)
Enclosure Material ABS
Grille Corrosion-resistant, powder-coated aluminum
Inputs Screw terminal
Colors Black or white
Height x Width x Depth 110.4 mm (4.35 in.) x 110.4 mm (4.35 in.) x 96.9 mm (3.81 in.)
Weight 0.6 kg (1.4 lbs.)
Shipping Weight 0.9 kg (2.0 lbs.)
Included Accessories N/A
Optional Accessories 10-watt transformer (AC-SM31-XFMR), Single gang junction box mounting plate (AC-SM31-MP)
Packaging One per box
Regulatory - UL 1480 (UEAY) planned
EN54-24 Planned
Regulatory - CE, RoHS, IP65 Approved
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