About the Definitive Technology UIW RCS II
Dynamic overhead sound from Def Tech
Dynamic overhead sound from Def Tech
Definitive Technology has a great-sounding option for your custom-installed audio system. The UIW RCS (Reference Line Source) II in-ceiling speaker uses an angled-baffle design to bring sound down and toward you, making it a great choice for the front left, center, or right channel in your home theater system.
Pair the UIW RCS II with Reference Line Source in-wall speakers for seamless, voice-matched sound throughout your room.

The integrated sealed enclosure helps deliver excellent sound while keeping dust and dirt away.
Dual passive radiators help deliver extra punch
The UIW RCS II pairs two 5-1/4" polypropylene midrange/bass drivers with a 1" aluminum dome tweeter to produce the natural, revealing sound Def Tech is known for.
Dual 6-1/2" pressure-coupled passive radiators help reinforce this in-ceiling speaker's impressive bass output.
A built-in enclosure elevates performance
One of my favorite features of the UIW RCS II is the back-box that's built onto the speaker.
This carefully designed enclosure helps the speaker deliver consistently focused, well-balanced sound no matter what kind of space is behind it in your ceiling. It also keeps dust and dirt out.
DIY installation
You can paint the included grille to have your speaker blend in with your room's décor.
If this is a do-it-yourself install, check out our guide to installing in-ceiling speakers, along with our selection of in-wall speaker wire.
Product highlights:
- ideal for an in-ceiling music system, or as part of a custom-installed home theater system
- built-in back-box ensures well-balanced sound and protects against dust and dirt
- angled-baffle design for directing sound toward your listening position
- 1" aluminum dome tweeter
- dual 5-1/4" polypropylene cone midrange/bass drivers with cast baskets
- dual 6-1/2" pressure-coupled passive radiators for extended bass response
- frequency response: 22-30,000 Hz
- nominal impedance: 8 ohms
- sensitivity: 92 dB
- magnetic grille is paintable to match your décor
- cutout dimensions: 14-3/8"W x 14-3/8"H
- overall dimensions: 15-1/2"W x 15-1/2"H
- mounting depth: 5-7/8"
- warranty: 5 years
- Our 60-day money-back guarantee
- MFR # UDSA
What's in the box:
Definitive Technology UIW RCS II owner's manual
- In-ceiling loudspeaker
- Grille
- 5 Long gaskets
- 1 Short gasket
- Paint mask
- Wall template
- Owner's Manual
- Online Product Registration Card
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More details on the Definitive Technology UIW RCS II

Features & specs
Features | ||
---|---|---|
Quantity in Package | Single | |
Tweeter | Hard-dome | |
Aimable Tweeter | No | |
Woofer Composition | Polypropylene | |
Woofer Surround | Butyl Rubber | |
Moisture-resistant | Yes | |
Outdoor-rated | No | |
Connector Type | --- | |
Bi-Amp Inputs | No | |
Built-in Back-box | Yes | |
Specs | ||
Tweeter Size | 1 | |
Midrange Size | N/A | |
Speaker Shape | Square | |
Woofer Size | 5.25 | |
Cutout Width | 14.375 | |
Cutout Height | 14.375 | |
Power Range (Watts) | 10-250 | |
Sensitivity | 92 dB | |
Impedance (Ohms) | 8 | |
Frequency Response | 22-30kHz | |
Parts Warranty | 5 Years | |
Labor Warranty | 5 Years |
Product Research
Features
D'Appolito Driver Array: The Definitive Technology UIW RCS II in-ceiling speaker features a D'Appolito driver array angled down and aimed at the listening area . The D'Appolito driver array consists of two 5.25" cast-basket midbass/midrange drivers and a 1" pure aluminum tweeter, as well as two 6.5" pressure-coupled planar low bass radiators. Because of its active driver/bass radiator combination the RCS II achieves an extended low-frequency response, which is deep and dynamic with a smooth and controlled roll-off that allows it to seamlessly blend with a subwoofer such as Definitive Technology's in-wall IWSub 10/10 or the UIW Sub Reference (sold separately).
Proprietary Wave Launch Technology: Proprietary Wave Launch (patent pending) baffle geometry and acoustic treatment materials serve to create the illusion that the speakers are directly in front of the listener rather than up in the ceiling. The precisely configured dual angled baffles incorporate a uniquely effective acoustic treatment which combines a computer-optimized ribbed surface with special dampening panels in order to achieve a linear uncolored sound combined with three-dimensional imaging in which acoustic events seem to effortlessly float in space.
Non-Resonant Sealed Enclosure: The RCS II 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. The performance of open back built-in speakers will vary depending on the nature of the ceiling cavity behind the speaker. But Definitive Reference series speakers with integrated enclosures sound superb every time.
Paintable: The UIW RCS II in-ceiling loudspeaker's grille and frame can be spray painted to match the color of your wall without any loss of sound quality. Simply remove the grille from the speaker and place it on a drop cloth, newspaper, or plastic sheet and spray paint it with canned spray paint that closely matches the desired finish/color (available at home improvement stores). A paint mask is supplied to protect the drivers when painting the frame.
Spring-Loaded Speaker Terminals: The UIW RCS II in-ceiling loudspeaker features a pair of heavy-duty, gold-plated, spring-loaded posts designed to accept up to 10 gauge wire, banana plugs (single only), or pin-connectors.
Applications: The Definitive Technology UIW RCS II is intended for use as an in-ceiling front main left, center or right channel speaker, as well as a rear or side surround speaker in custom installed home theater systems of the highest quality. In addition, it can be used as a superb left or right speaker in a high quality stereo music system.
In-Ceiling Installation: Six rotating dogleg clamps and four 3.5" wood screws make the RCS II easy to install in either new or existing construction and provide secure, non-resonant mounting for ultimate audiophile performance free of vibrations and buzzes. In-ceiling installation requires a cutout of 14.375" (w) x 14.375" (h) x 5.875" (d). A 1" of clearance is required around the cutout, on the outside mounting surface, to clear the in-ceiling speaker's bezel. A 1.25" of clearance is required around the cutout, on the inside mounting surface, to clear the dogleg clamps.
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