SoundTube SM31-EZ Surface Mount Speaker in White

The SM31-EZ is a premium full range 3 inch surface mount speaker, with overall dimensions smaller than a 4 inch sphere. The speaker incorporates a theft and corrosion resistant mounting mechanism with indexed swivel joint for complete hemispherical aiming. 


SM31-EZ speaker components have been weatherized for indoor and outdoor applications. The SM31-EZ is an 8 ohm speaker with an ultra-low profile ZeroReflection ABS enclosure (4 inch diameter by 3.5 inch deep, including mounting plate).

  • ColorWhite
    Manufacturer’s Suggested Retail Price 
    Manufacturer’s CategorySM-EZ Economical Surface Mount
    Height4.35 in / 110.5 mm
    Width/Diameter4.35 in / 110.5 mm
    Shipping Weight1.85 lbs / 0.84 kg
    Carton Height6.25 in / 158.75 mm
    Carton Length6.5 in / 165.1 mm
    Carton Width6.25 in / 158.75 mm
    CertificationsCE, RoHS, UL1480A
    Enclosure PropertiesABS Glass Fiber Reinforced, Injection Molded, Sealed
    Enclosure Volume60 cu in / 983.22 cu cm
    Optional AccessoriesJunction Box (AC-SM31-JBOX)|White Transformer (AC-SM31-XFMR-WH)|White Wall Plate (AC-SM31-MP-WH)|White Grille (GRL-RS31-WH)
    Source InputsTerminal Strip
    Coverage Angle (-6dB @ 2kHz)43°
    Directivity Factor (Q) (Averaged 100Hz – 10kHz, @ 2kHz)4.9 and 7.1
    Directivity Index (DI) dB (Averaged 100Hz – 10kHz, @ 2kHz)5.1dB and 8.5dB
    Frequency Response (± 10 dB)120 Hz – 22 kHz
    Frequency Response (± 3 dB)170 Hz – 14 kHz
    Grille PropertiesAluminum, Powder-Coated
    Low Frequency Voice Coil0.75 in / 19 mm
    Magnetically BoostedNo
    Max. Continuous Power RMS20W
    Max. Program Power40 W
    Minimum Impedance (Ω Ohms)8 Ω
    Mounting Depth3.81 in / 96.8 mm
    Nominal Impedance (Ω Ohms)8 Ω
    Fullrange Driver3″ Polypropylene driver with butyl rubber surround
    Sensitivity dB @ 1W/1M85 dB
    Sensitivity dB @ 2.83V/1M85 dB
    Transformer Options25 / 70.7 / 100 V