SI 28 Retired

Two-Way Surface Mount Speakers with 8" Woofer
Key Features
  • Exclusive conical horn design
  • 8 ohm nominal impedance
  • 1" (2.5 cm) ferrofluid-cooled, aluminum dome tweeter
  • 8" (20.3 cm) long-throw woofer with dual tuned bass reflex ports
  • Frequency range: 50 Hz to 20 kHz
  • 90 watts continuous pink noise, 180 watts continuous program
The Extron SI 28
Model Version Description Part #
SI 28 Surface Mount - 8" Woofer, Black, Pair 42-073-02 Retired
SI 28 Surface Mount - 8" Woofer, White, Pair 42-073-03 Retired

This product has been retired.
Suggested Replacement
SM 28

The Extron SI 28 two-way surface mount speaker features a ferrofluid-cooled, aluminum dome tweeter coupled to an Extron exclusive conical horn design for minimum phase shift and a flat response over the mid- and high-frequency ranges. Harsh tonal qualities due to cancellation in portions of the frequency range caused by phase shifting are all but eliminated with this exclusive conical horn design. A long-throw woofer with large magnets provides solid low-frequency response. This approach to crossover design assures a smooth transition from bass through midrange to the high frequencies, delivering optimum voice and music reproduction. An input power-limiting protection circuit is included for preventing woofer and tweeter damage due to overdriving.

This System INTEGRATOR® Series speaker is ideally suited for classrooms, conference rooms, and boardrooms.

The SI 28 features an 8" (20.3 cm) long-throw woofer, a 1" (2.5 cm) tweeter, 90 watts continuous pink noise and 180 watts continuous program capacity, and a frequency range from 50 Hz to 20 kHz. This speaker has a nominal impedance of 8 ohms with a durable, high-impact housing.

Included with the SI 28 is Extron's exclusive, patented V-Lock® mounting hardware, which facilitates easy, secure installations and allows for wide 60° horizontal and 55° vertical travel as well as 360° rotation. This flexible design allows the speakers to be placed vertically or horizontally to meet a variety of placement needs.

The SI 28 is sold in pairs and is available in a black or white finish, and includes a 5 year parts and labor warranty.


  V-Lock Replacement V-Lock® Wall Assembly for Extron Surface Mount Speakers
  SPK 14 14 AWG Speaker Cable
  SPK 16 16 AWG Speaker Cable
  SPK 18 18 AWG Speaker Cable
  CS 123T Full-Range 70/100 V SpeedMount Ceiling Speaker System
  CS 3T Full-Range Open Back Ceiling Speakers with 70/100 V Transformer
  FF 120T Full-Range Flat Field Speakers with 1' x 2' Low Profile Enclosure and 70/100 V Transformer
  FF 220T Full-Range Flat Field Speakers with Low Profile Enclosure and 70/100 V Transformer
  SF 228T Two-Way SoundField Ceiling Tile Speakers with 8" Woofer and 70/100 V Transformer
  SF 26X Two-Way SoundField Open Back 8 Ohm Ceiling Speakers


SI 28 Surface Mount Speaker
Audio/acoustic and electrical
   Speaker type 2-way surface mount speaker
   Frequency range 50 Hz to 20 kHz, -10 dB, full space
   Power capacity 90 W continuous pink noise
180 W continuous program
   Nominal sensitivity 90 dB SPL, 1 W, 1 m, full space
   Nominal impedance 8 ohms
   Crossover frequency 2.1 kHz
   Woofer (1) 8.0" (203 mm) polypropylene cone with moisture resistant coating
   Tweeter (1) 1.0" (25 mm) aluminum dome
   Overload protection Full range power limiter, protecting the tweeter, woofer, and crossover
   Input connector (1) 2-pin spring terminal
   Package 2 speakers (1 pair)
   Temperature/humidity Storage: -40 to +158 °F (-40 to +70 °C) / 10% to 90%, noncondensing
Operating: +32 to +122 °F (0 to +50 °C) / 10% to 90%, noncondensing
   Mounting Vertically and horizontally wall mountable with included hardware: wall mountable V-lock brackets
    NOTE     V-lock brackets can be angled up to 20° upward, 35° downward, 30° to the left, 30° to the right, and rotated 360°.
   Enclosure type Plastic, trapezoidal, with metal grille and bass reflex port
   Enclosure outer dimensions 16.5" H x 11.5" W x 8.6" D
(41.9 cm H x 29.2 cm W x 21.9 cm D)
   Product weight Single: 15 lbs (6.8 kg)
   Product warranty 5 years parts and labor
    NOTE     All nominal levels are at ±10%.
    NOTE     Specifications are subject to change without notice.


Application Diagram

Panel Drawing

Panel Drawing
© 2020 Extron. Specifications are subject to change without notice.