Extron SM 3 (part number 42-133-03) — a compact one-way surface mount speaker pair finished in white for space-constrained wall audio.

The SM 3 uses a single 3-inch paper cone driver with a tuned bass reflex port inside a shallow trapezoidal enclosure that protrudes less than 4 inches from the wall when mounted with the included 0° plate, meeting ADA Section 307 protrusion limits. The same concealed SpeedMount hardware used across Extron's surface speaker line lets a low-voltage contractor terminate cable to the mounting plate during rough-in, with the speaker added later by a separate crew.

Key Capabilities

• 15 W continuous pink noise, 30 W continuous program power handling per pair
• Frequency range of 100 Hz to 20 kHz (-10 dB, full space)
• Wide 120° horizontal and 130° vertical coverage angles
• Includes both 0° and 10° mounting plates for flexible aiming
• ADA-compliant 4-inch maximum protrusion with 0° mounting plate

Where It Is Used

The SM 3 fits small to medium classrooms and conference rooms where wall space is limited and a low-profile, ADA-compliant speaker is required alongside a division-of-labor installation workflow.

Specifications at a Glance

• 3-inch paper cone driver, 8 ohm nominal impedance
• 8.75" H x 5.75" W x 4.0" D with 0° mounting plate attached
• 2.0 lbs single speaker weight
• 83 dB nominal sensitivity at 1 W, 1 m
• 5-year parts and labor warranty

Also referenced as Extron SM3, SM-3, part number 42133-03.