Klipsch CDT-3650-C II In-Ceiling Speaker (Each) at Vinyl Sound Toronto Canada

The CDT-3650-C II is a 6.5-inch two-way in-ceiling speaker from Klipsch (Indianapolis, Indiana, USA), available at Vinyl Sound in Toronto, Canada. Built for whole-house audio, multi-room distributed systems, and home theater installations, the CDT-3650-C II pairs a 1-inch Aluminum compression driver mated to a swiveling 100-degree Tractrix® horn with a fully pivoting 6.5-inch IMG woofer, delivering 93 dB sensitivity and a frequency range of 63 Hz to 23 kHz. The SlimTrim magnetic grille reduces visible frame size by 90 percent over the original CDT-3650-C, creating a discreet, near-invisible ceiling installation.

Horn-Loaded Performance with Tractrix® Technology

The CDT-3650-C II carries forward the core Klipsch design principle that has defined the brand since 1946: a rigid aluminum compression driver mated directly to a horn. In this case, the horn is Klipsch's proprietary Tractrix® geometry, a mathematically optimized flare that allows sound to exit with minimal turbulence and distortion. The 100-degree symmetrical dispersion pattern of the Tractrix® horn delivers high-frequency energy more precisely and with greater efficiency than conventional dome tweeters, which scatter sound broadly and introduce reflected energy that blurs fine sonic detail. The aluminum diaphragm of the compression driver is stiff yet lightweight, working in conjunction with a precision phasing plug at the horn throat to produce coherent, low-distortion output across the full treble range.

Controlled Dispersion Technology: Full Woofer and Tweeter Aiming

The "CDT" designation identifies what sets this speaker apart from nearly every competing in-ceiling model in its class. Klipsch's Controlled Dispersion Technology uses a patent-pending gimbal mechanism that allows both the tweeter and the woofer to be independently aimed toward the primary listening area. The swiveling Tractrix® horn tweeter can be directed toward any seating position, while the 6.5-inch IMG woofer can rotate a full 360 degrees and pivot up to 15 degrees in any direction. This dual aiming capability means midbass and high-frequency energy both arrive on-axis at the listener, producing better vocal clarity, more lifelike imaging, and a more cohesive overall sound compared to fixed-position in-ceiling designs from competitors such as the Polk Audio RC80i or the Sonance C6R.

6.5-Inch IMG Woofer

The low-frequency driver in the CDT-3650-C II is a 6.5-inch injection-molded graphite (IMG) cone woofer. IMG cone technology produces a diaphragm that is simultaneously rigid and lightweight, minimizing cone breakup and coloration in the critical midrange frequencies where voice and instrument presence reside. The woofer operates within an ABS infinite baffle enclosure, flush with the ceiling surface, and its pivoting mount allows it to be independently angled for optimal midbass coverage wherever the speaker must be positioned in the room.

SlimTrim Magnetic Grille and Treble Attenuation Switch

The redesigned SlimTrim aluminum grille reduces the visible frame size by 90 percent and grille depth by 80 percent compared to the original CDT-3650-C model. The magnetic attachment system requires no tools and eliminates mechanical resonance that can color the speaker's output at high volumes. The grille is paintable to match any ceiling color. A rear-mounted treble attenuation switch allows the installer to reduce high-frequency output in acoustically challenging environments, such as rooms with hard floors, large glass surfaces, or parallel reflective walls, where a natural tonal balance requires a gentler top end.

Key Features

• 1-Inch Aluminum Compression Driver with Tractrix® Horn: A stiff, lightweight aluminum diaphragm paired with Klipsch's 100-degree symmetrical Tractrix® horn delivers precise, low-distortion high-frequency reproduction with greater efficiency than standard dome tweeters.
• 6.5-Inch Pivoting IMG Woofer: The injection-molded graphite cone provides rigid, low-coloration bass and midrange response. The woofer rotates 360 degrees and pivots 15 degrees for independent aiming toward the listening area.
• Controlled Dispersion Technology (CDT): A patent-pending gimbal mechanism allows both the tweeter and woofer to be independently aimed, directing both high and midbass frequencies precisely at the listener from any ceiling mounting position.
• 93 dB Sensitivity: High efficiency makes the CDT-3650-C II ideal for whole-house multi-zone audio systems where long wire runs reduce available amplifier power at the speaker terminals.
• Treble Attenuation Switch: A rear-panel switch allows the installer to reduce high-frequency output in reflective or acoustically bright rooms, providing better tonal balance without equalizer adjustment.
• SlimTrim Magnetic Grille: The new aluminum, paintable grille reduces visible frame size by 90 percent and grille depth by 80 percent over the previous model, attaching magnetically with no tools for a seamless ceiling appearance.
• 2,800 Hz Crossover Frequency: A precisely engineered crossover hands off frequencies cleanly between the woofer and compression driver, avoiding overlap and phase issues in the vocal midrange.
• 12-Gauge Wire Compatibility: Spring-clip terminals accept wire up to 12 gauge, accommodating long cable runs without excessive resistance.

Technical Specifications

Connections at a Glance

• Speaker Terminals: Spring-clip terminals accepting wire up to 12 AWG or pin connectors
• Treble Attenuation Switch: Rear-panel switch for high-frequency level adjustment
• Grille Attachment: Magnetic, tool-free SlimTrim aluminum grille

Frequently Asked Questions

What is the Klipsch CDT-3650-C II?

The Klipsch CDT-3650-C II is a 6.5-inch two-way in-ceiling speaker from Klipsch's Reference custom installation lineup, featuring a 1-inch aluminum compression driver mated to a swiveling 100-degree Tractrix® horn, a pivoting IMG woofer, and Controlled Dispersion Technology that allows both drivers to be independently aimed toward the listening area. It delivers 93 dB sensitivity, handles 50W RMS, and covers 63 Hz to 23 kHz, making it suited for whole-house audio, stereo two-channel listening, and home theater surround use.

How does the Klipsch CDT-3650-C II compare to the Polk Audio RC80i or Sonance C6R?

The CDT-3650-C II outperforms the Polk Audio RC80i and Sonance C6R in two key areas: driver aiming and tweeter technology. Both the Polk and Sonance models use conventional fixed-position dome tweeters without a horn, which scatter high frequencies broadly and rely heavily on reflected sound to fill a room. The CDT-3650-C II's Tractrix® horn controls dispersion to a defined 100-degree pattern, and its CDT gimbal mechanism allows both the tweeter and woofer to pivot independently toward the seated listener. The result is significantly better on-axis response, higher sensitivity at 93 dB, and cleaner vocal and instrumental detail in typical residential installations.

Can the Klipsch CDT-3650-C II be used for whole-house distributed audio?

Yes, the CDT-3650-C II was specifically engineered for whole-house distributed audio applications. Its 93 dB sensitivity means it produces high output even when amplifier power is reduced by long wire runs between zones, which is one of the most common challenges in multi-room audio system design. The spring-clip terminals accommodate wire up to 12 AWG, which is the recommended gauge for minimizing resistance loss over extended cable lengths to remote rooms.

What is IMG and why does it matter for an in-ceiling woofer?

IMG stands for Injection-Molded Graphite, a cone material that combines the light weight of polymer with the rigidity of a graphite-reinforced matrix. In an in-ceiling speaker, a rigid cone resists flexing at higher output levels, which means the woofer produces less coloration and distortion in the critical midrange frequencies where vocals, acoustic instruments, and dialogue sit. The CDT-3650-C II's 6.5-inch IMG cone delivers controlled, accurate bass and midrange from the same driver, contributing to the speaker's cohesive two-way performance.

What does the treble attenuation switch do on the CDT-3650-C II?

The treble attenuation switch on the rear of the CDT-3650-C II reduces the high-frequency output level, allowing the installer to compensate for acoustically bright rooms without using an external equalizer. Rooms with hardwood floors, large windows, or low ceilings tend to reflect treble energy aggressively, which can make speakers sound harsh or fatiguing. Engaging the treble attenuation switch softens the top end at the source, producing a more neutral tonal balance that suits the room's acoustic character.

Where can I buy the Klipsch CDT-3650-C II in Toronto or Canada?

The Klipsch CDT-3650-C II is available at Vinyl Sound, an authorised Klipsch dealer in Toronto, Canada. Vinyl Sound carries Klipsch's full custom installation speaker range and can assist customers across the Greater Toronto Area with product selection, system design recommendations, and guidance on compatible amplification, installation accessories, and fire-rated enclosures.

Is the Klipsch CDT-3650-C II sold individually or as a pair?

The CDT-3650-C II is priced and sold as a single speaker unit. For stereo listening in a room, two units are needed. For a distributed whole-house audio system or home theater surround setup, the quantity required depends on the number of zones or speaker positions in the installation plan.

Does the CDT-3650-C II require a fire-rated enclosure?

The CDT-3650-C II operates as an infinite baffle design and does not require an enclosure for standard drywall ceiling installations. However, Klipsch offers the optional ME-650-C fire-rated speaker enclosure for installations where local building codes require acoustic separation between floors or fire-rated assemblies between rooms. The optional IK-650-C installation kit with mud ring, wire tie, and color-coded brackets is also available separately for code-compliant and professional custom integration builds.