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Definitive Technology® Reference Line Source III 5.25" White In-Wall Speaker

Model #: UIW RLS III
Definitive Technology
At a Glance
The Reference Line Source III (RLS III) is an enclosed full range loudspeaker engineered for flush mount in-wall installation. It features a non-resonant sealed medite (a dense wood product) enclosure to deliver the tight, detailed bass and uncolored midrange of audiophile free-standing speakers in every installation.
Available in Store Only
$699.00Save $NaN

Get to know this product.

The performance of open back built-in speakers will vary depending on the nature of the wall/ceiling cavity behind the speaker. But Definitive Reference speakers with integrated enclosures sound superb every time. Rotating dogleg clamps make the RLS III easy to install in either new or existing construction and provide secure, non-resonant mounting for ultimate audiophile performance free of vibrations and buzzes.

  • Two 5-1/4 inch cast basket drivers and 5-1/4 inch pressure-coupled Low Bass radiators for impressive deep bass with high impact punch
  • Integrated wood enclosure ensures consistent high performance every time
  • One 1 inch Pure aluminum dome tweeter
  • Installs in either new or existing construction applications
  • Available individually
  • White Finish
Useful Documents


Speaker TypeIn-Ceiling Speaker
Sold AsEach
Weight14.5 lbs (6.58 kg)
Shipping Cartons30" (76.2 cm) h x 9.5" (24.13 cm) w x 9" (22.86 cm) d
Shipping Weight16 lbs (7.26 kg)
Recommended Amplification10 – 325 watts

Driver Complement

Tweeter(1) 1" (2.54 cm) d (Round) - Tweeter
Mid/Woofer(2) 5.25" (13.34 cm) d (Round) - Mid/Woofer
Bass Radiator(2) 5.25" (13.34 cm) d (Round) - Bass Radiator

In-Wall Mount

Dimensions23.75" (60.33 cm) h x 5.88" (14.94 cm) w
Clearnace Required for Mounting Dogs (add to each side of cutout)0.88" (2.24 cm)


Speaker Inputs(1) Pair of Heavy Duty, Spring Loaded - Gold-Plated

Audio Quality

Total Frequency Response24 Hz to 30 Hz
Nominal Impedance8 ohms
Max Sensitivity (1 watt @ 1 meter)92 dB


A/V Receiver Crossover SettingsSmall (40 Hz)


Cabinet Warranty5 Years
Drivers Warranty5 Years
Original Purchaser OnlyYes

Included Accessories

Wall Mounting Template1
Paint Mask1
Paintable Grille1
Self Adhering Foam Gasket1

Misc. Specs

Product Weight (lbs.)14.5
Color Finish NameWhite
RMS Power Handling (Watts)325
Impedance8 ohms
Number of Speakers1
Speaker TypeIn-Wall Speakers
Depth (in.)3.81
Height (in.)23.75
Width (in.)5.88
WarningProposition 65 Warning for California Residents