PSB CS650
Overview
The PSB CS650 is the flagship in-ceiling speaker of the CustomSound 600 series. It brings over fifty years of Canadian acoustic research into a flush-mount format. Its development traces back to the journey of PSB founder Paul Barton, who began in the 1970s in St. Jacobs, Ontario assembling student kits, and later grew the brand internationally.
A woofer that draws on the DNA of prestige floorstanders
The 165 mm bass driver is the beating heart of the CS650. Its carbon-fiber-reinforced injection-molded polypropylene cone doesn’t just reproduce low frequencies—it sculpts them with authority rarely found in this category. This specific cone formulation, directly inherited from developments for the Imagine T3 floorstander, gives the material remarkable rigidity while maintaining optimal internal damping. The butyl rubber surround ensures controlled excursion even during the most demanding passages, while the high-temperature voice coil withstands the thermal stress of extended, high-level listening.
Integrating carbon particles into the polypropylene matrix fundamentally alters the cone’s behavior. The microfibers create a three-dimensional network that increases the speed of wave propagation in the material, pushing breakup modes well beyond the usable bandwidth. This technology enables bass extension down to 48 Hz, an unusually generous performance for a speaker designed to operate in an open-back installation without the assistance of an enclosed volume.
The very geometry of the chassis has been meticulously optimized. Radial ribs reinforce the structure while minimizing unwanted reflections toward the rear of the cone. The engineered basket shape maintains a consistent acoustic load across the entire circumference of the diaphragm, ensuring uniform response regardless of listening position in the room.
The titanium tweeter: cutting-edge technology tailored for in-ceiling mounting
The 25 mm titanium dome is far more than a premium material choice. Shared with the prestigious Imagine T3, this technology benefits from a sophisticated waveguide that radically reshapes its acoustic behavior. The Wave Guide doesn’t just control directivity: it allows the tweeter to extend lower in frequency, creating an optimal handoff to the woofer in the critical crossover region set at 1800 Hz.
The ferrofluid surrounding the voice coil serves several essential functions. This magnetic fluid—composed of ferromagnetic nanoparticles suspended in a specially formulated synthetic oil—first ensures efficient heat dissipation. Heat generated by the coil is transferred to the magnetic structure, which acts as a heatsink, enabling the tweeter to handle high power without dynamic compression. The ferrofluid also provides calibrated mechanical damping that linearizes response and eliminates parasitic resonances. Contrary to popular belief, this substance does not “dry out” over time under normal operating conditions—only extreme overheating can alter its properties.
The indexed tweeter adjustment is a remarkable technical feature. A ball-joint mechanism allows precise orientation of the dome’s acoustic axis toward the listening area, compensating for placement constraints imposed by architecture. Typically reserved for professional models, this function turns every installation into a bespoke solution.
Architectural integration engineered down to the last detail
The rotating dogleg mounting system reflects a pragmatic approach to installation. These high-strength steel mechanisms deploy behind the wall with a simple twist of a screwdriver, creating progressive, even clamping around the entire perimeter. This design eliminates localized pressure points that could deform drywall or cause unwanted vibrations.
Frameless magnetic grilles underscore the attention to aesthetics. Available in round and square versions, they suit diverse design philosophies. The perforated steel accepts spray paint for perfect color matching, while the acoustically transparent fabric preserves the sonic signature. Powerful neodymium magnets ensure a secure hold while allowing instant removal for adjustments.
The supplied cutout template removes guesswork during drilling. With its precisely calibrated 212 mm diameter, it guarantees a perfect fit that optimizes acoustic coupling with the ceiling. Optional PRE-600 pre-construction brackets allow you to reserve the exact location even before drywall installation, greatly simplifying new-build projects.
Adjustments that turn any room into an auditorium
Independent level switches for the tweeter and woofer provide uncommon tuning flexibility. Settable to 0 dB or +3 dB, they let you compensate for the specific acoustic characteristics of each environment. A heavily damped room will benefit from a slight treble boost, while a more reverberant space will prefer the neutral position. This flexibility turns the CS650 into an acoustic chameleon capable of adapting to the most varied layouts.
The 4th-order Linkwitz–Riley crossover at 1800 Hz deserves special attention. This complex topology, requiring more components than a conventional network, ensures steep 24 dB/octave slopes and perfect acoustic summation between the two drivers. Acoustic phase remains coherent across the entire bandwidth, preserving transient integrity and soundstage precision.
Gold-plated spring terminals accept bare wire up to 12 AWG, single banana plugs, or pin connectors. This technical choice prioritizes reliability and ease of installation in the confined spaces of ceilings, while ensuring a rock-solid electrical connection over the long term.
Technical Specifications
Key Features
- Deep, accurate bass: 165 mm fiber-filled polypropylene woofer
- Clear treble: 25 mm titanium tweeter with ferrofluid and adjustable waveguide
- 1800 Hz LR4 crossover: smooth transition between bass and treble
- Voicing aligned with other PSB speakers for multi-room or home theater
- Easy installation: secure mounting, templates and brackets included
- Discreet design: magnetic round and square grilles, paintable
Acoustic Response
- On-axis frequency response @ 0° ±3 dB: 48 – 20,000 Hz
- Sensitivity
- Anechoic: 86 dB
- Listening room: 88 dB
Electrical Characteristics
- Impedance
- Nominal: 6 Ω
- Minimum: 4 Ω
- Recommended input power: 10 – 100 W
Acoustic Design
- High-frequency driver: 25 mm titanium dome with ferrofluid
- Low-frequency driver: 165 mm injection-molded fiber-filled polypropylene with rubber surround
- Crossover: 1800 Hz, LR4
- Type: open back
Dimensions and Installation
- Cutout diameter: 212 mm
- Mounting depth: 114 mm
- Round grille diameter: 240 mm
- Square grille: 241 x 241 mm
- Weight: 2.1 kg per speaker
Finish
- White with round and square grilles included, paintable
Frequently Asked Questions
What is the main difference between the CS650 and the CS610/CS630 models in the same series?
The CS650 stands out with its 1-inch titanium tweeter with waveguide and indexed adjustment, whereas the CS610 uses a 3/4-inch aluminum dome. The CS650’s woofer also incorporates optimizations derived from the Imagine T3 for increased sensitivity and reduced distortion at high volume. The CS630, meanwhile, offers a stereo/surround configuration with a dual voice coil and two tweeters, ideal for small spaces requiring stereo sound from a single point.
Are backcans necessary to optimize performance?
BCN-600 backcans are not mandatory but can improve acoustic isolation between rooms and offer better bass control in certain setups. The CS650 is designed to operate in an open-back configuration and delivers its nominal performance without a backcan. Adding a backcan may be appropriate in buildings requiring enhanced soundproofing or to limit sound transmission to adjacent floors.
How should the CS650s be positioned in an Atmos home theater configuration?
For Atmos height channels, place the CS650s slightly ahead of the main listening position, at an angle of 30 to 55 degrees relative to the listener. The tweeter’s directional adjustment should be aimed toward the listening area. The distance between front and rear height speakers should roughly match the width of the listening area. Thanks to their wide dispersion and adjustable orientation, the CS650s are forgiving of placement variances.
Does the tweeter’s ferrofluid require maintenance or periodic replacement?
No. The ferrofluid used in the CS650 tweeter is a permanent emulsion that does not degrade under normal use. Contrary to persistent rumors, it does not “dry out” over time. Only extreme overheating due to operation outside specifications could alter its properties. In normal domestic use, even intensive, the ferrofluid retains its characteristics for the speaker’s lifetime.
Can the CS650 be used as a main speaker in a music system?
Absolutely. With its extended 48 Hz to 20 kHz response and its ability to handle 100 watts, the CS650 is perfectly suitable as a main speaker for music. The tweeter derived from the Imagine T3 ensures detailed high-frequency reproduction, while the premium woofer provides bass authority that’s surprising for a flush-mount speaker. The level adjustment lets you tailor tonal balance to personal preferences.
What cable gauge do you recommend for powering the CS650?
14 AWG cable is suitable for runs up to 15 meters, ensuring negligible losses. For longer distances or a high-end permanent installation, opt for 12 AWG. The terminals accept conductors up to 12 AWG. Use CL2 or CL3 certified cable for in-wall installations, in accordance with electrical codes.
Is the 114 mm mounting depth compatible with all types of ceilings?
This depth suits most modern residential constructions with standard joists. However, verify available space, particularly in suspended ceilings or older buildings. The CS650’s open-back design does not require additional space beyond the mounting depth, unlike models with an integrated backcan.
- Eco-contribution included in the sale price.
