Definitive Technology Di 3.5R In-ceiling Speaker


Disappearing In-Wall Design: 

  • The DI 3.5R features Definitive Technology's Disappearing In-Wall Design.
  • The mounting flange thickness of the in-wall/in-ceiling loudspeaker is no more than 2.5mm (0.099") and is completely covered by the grille that stands a mere 3.5mm (approx 0.125") from the wall surface.
  • The grille is "micro-perf", that while presenting an opaque appearance, actually has more open area than typical perforated metal grilles allowing the sound to pass through with less interference and better fidelity.
  • Behind the metal grille is an acoustically transparent proprietary cloth scrim that effectively blacks the dark "shadow" of the black speaker parts from showing through the grille.

Pivoting Aluminum Dome Tweeter with Waveguide: 

  • The DI Series in-wall/in-ceiling loudspeaker uses Definitive Technology's proprietary ceramic-coated annealed aluminum 3/4" dome tweeter.
  • The DI 3.5R tweeter is post mounted, and the tweeter housing is specially smoothed and shaped to use it as an extremely effective low-diffraction waveguide.
  • The aluminum dome tweeter features a pivoting design which allows you to focus the sound toward or away from your listening area depending on the application.

BDSS Drivers: 

  • The DI 3.5R uses a 3.5" BDSS driver for wide-bandwidth accurate frequency response, broad dispersion, low distortion, and maximum detail retrieval.
  • The 3.5" BDSS driver cone is supported by specially tuned soft rubber surrounds at both the outer and inner edges.
  • The double surrounds allow the cone to have longer excursion without distortion.
  • As bass output is a function of both a cone's diameter and excursion, the higher excursion BDSS system brings the benefit of higher bass output from smaller drivers.
  • The tiny DI 3.5R has the bass output and dynamic range of a typical 4-1/2" driver.

Linkwitz-Riley Crossover Network: 

  • The Definitive Technology DI 3.5R's second order (12dB/octave) Linkwitz-Riley crossover offers a smooth frequency and phase transition from driver to tweeter for natural midrange response and excellent off-axis performance.
  • A Zobel network flattens the impedance curve of the speaker making it easier for today's digital amplifiers to drive the speakers.
  • Custom tight-tolerance (+/- 5%) components are used throughout the crossover for superb unit-to-unit performance consistency.
  • Superior metal film capacitors are used in the high-pass section and the Zobel network for extended high frequency response.
  • Oversize inductors (coils) avoid saturation thereby maintaining the wide dynamic range capabilities of the driver.


  • The dimpled AeroRing is soft Sanoprene rubber and serves several important functions.
  • First, it damps the basket/flange assembly nearest its thinnest part (the flange) to prevent resonance.
  • Second it prevents the grille from rattling in the unlikely event that it makes contact with the speaker frame.
  • It also provides a smooth transition for the waveform coming off the cone.
  • Similar to the dimples on a golf ball that reduce turbulence to aid in longer flight, the dimples on the AeroRing promote smooth "laminar" air flow over the surface thereby reducing diffraction effects.
  • The DI Series in-wall/in-ceiling loudspeakers sound clear, natural, and disperse their sound over a wide area.

PolyStone Basket: 

  • The driver basket, mounting flange, and mounting system of the DI 3.5R is one piece of cast PolyStone;
  • Definitive's exclusive formulation of polymers and minerals that combine the rigidity and strength of metal with the resonance damping properties of plastics.
  • As a result of the one-piece mounting system, the DI 3.5R offers increased strength, a compact size, and maximized cone area.
  • Besides being more space efficient than multi-piece construction, it also contributes to the superior sound quality of the DI Series speakers.


  • The DI 3.5R features a pair of heavy-duty, gold-plated, spring-loaded wire terminals that have oversized holes to accept up to 10 gauge wire.

Definitive's GaussGrip System:

  • Definitive's GaussGrip system securely holds the grille of the in-wall/in-ceiling loudspeaker in place with powerful magnets.
  • Simply lay the grille over the speaker and its secure.
  • Taking off the grille is just as easy and fast; no special tools that can chip the grille paint are required.
  • All you need to remove the grille is your fingers.

Paintable Grille: 

  • The DI Series in-wall/in-ceiling loudspeaker's white "micro-perf" cloth grille can be spray painted to match the color of your wall or ceiling 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; or with indoor latex paint using an airbrush or spray gun (available at home improvement stores).
  • The paint must be diluted to a 6:1 ratio of latex paint to water.
  • Do not remove the backing cloth (scrim). Apply the paint in a series of thin coats sprayed at 45-60 degrees from the grille surface, allowing each coat to fully cure before applying additional coats.
  • To ensure that the paint distribution is evenly applied, each coat should be applied from 4 different directions (N,S,E, & W) to ensure an even coverage on the grille.
  •  The grille must be spray painted detached from the speaker. Do not paint the grille with a brush or roller.

Mounting Options


  • The DI 3.5R is especially suited for use in multiple pairs to provide more uniform sound coverage in large rooms.


  • The DI 3.5R can be mounted in-ceiling using the integrated rotating clamps and four mounting screws, or using an optional pre-construction bracket (73535RRIK, sold separately).
  • A cutout template is supplied to help you cut a 3-3/4" diameter hole.
  • You will need to allow at least 7/16" of space around the cutout and have at least 2-1/2" of clearance for mounting depth (using 1/2" thick mounting surface).
  • An additional 1-1/8" clearance from the edge of one side of the cutout inside the mounting surface is needed to provide clearance for the speaker's crossover.

Optional Pre-Construction (Rough-In) Brackets: 

  • The optional DI Series pre-construction rough-in brackets provide a simple way to mount these in-wall/in-ceiling loudspeaker during pre-construction or remodeling of your home.
  • The center rings are fabricated from heavy duty painted stamped steel.
  • There are no sharp metal edges to cut an installer's hands and they are ultra rigid, so that when drywall is laid over and cut the brackets will not bend or break.
  • The two 12" wings are painted perforated metal that snap onto the center ring in a variety of positions to cover almost any installation.
  • The wings can be attached with nails, staples or screws;
  • and can be bent and easily trimmed with tin snips.
  • They are also thin enough to make stud notching simple.
  • The wire tie loop easily breaks away when the speaker is installed. DI Rough-in Brackets are packaged two to a carton.
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