T3652-S

Curious headline? Perhaps, though rest assured I harbour no machination. It more pertains to where these components fit into the grand scheme of all things Rockford Fosgate. Because when talking about this American-born company, one needs to appreciate its rather awe-inspiring audio ubiquity. Rockford has been producing audio components for decades, a record that naturally leads to a substantial and ever-expanding stable of goodies.

Where these comments gain momentum is when you’re the poor coot deciding which ones to purchase. We’d never advise you to simply rush out and spend the most money you can (unless Lotto has been especially kind to you). Nor should you go for the cheapest components you can find, lest you find yourself with a product that’s exactly that. Research is the key when looking for value, and value is what Rockford Fosgate’s 3-series components were designed to personify.

Rockford actually makes two ranges above the 3-series and, although they may look better on paper in ultimate performance terms, the reality is that the 3-series offers arguably the best ratio of performance to monetary value.

SAME BUT DIFFERENT
Rockford designed the T3652-S to fill the middle ground of its ranges. Although the component set isn’t completely a ‘back to the drawing board’ design in the true sense of the term, they do still possess many a new or improved technology, both electrically and in metallurgical terms. Designed to fit most later model cars, the T3652-S is a 2-way component set comprising two 6.5-inch midranges, two 1-inch tweeters and, of course, two matching crossovers.

The diametrically challenged driver of the set is the T3T tweeter; a neat design where the most clever technology lies within its material employment. This starts with its 25mm dome, constructed from a liquid crystal polymer material (LCP); a material sure to get metallurgic propeller heads such as I excited. However we’ll spare you a techno-thesis, suffice to say that LCP is used in both the tweeter and midrange construction because it’s extremely unreactive and inert, meaning it reproduces a very neutral sound with little colouration. It’s also fire resistant but here’s hoping you won’t reach such a point to test this attribute.

The diaphragm is fastidiously designed with a rounded circular shape which enhances its strength and combats distortion. The dome is suspended in situ via a treated silk surround with movement coming courtesy of the motor beneath, comprising of a 4-ohms voice coil wrapped around a thermally-efficient former. The former is carefully situated in relation to the dense neodymium magnet to ensure movement is keep strictly within the upper and lower flux densities, the ensuing result being extremely precise reciprocations. The motor is not only designed to cover a wide band of frequencies but also to disperse the sound in a wide azimuth; projecting it forward of the driver. This is not achieved solely by dome shape and material though; there’s also a fair bit happening behind the scenes.

Beneath the dome is a carefully designed labyrinth chamber complete with damping material that deals with those undesirable back waves. The entire motor is sealed within the confines of a steel chamber and although it’s thermally efficient Rockford hasn’t left anything to chance, opting for a ferrofluid cooling system to ensure the internals don’t become molten under duress. This allows for a power handling ability of 125 watts continuous while the aforementioned suspension provides a peak ability of 250 watts.

The T3652 midrange is also the home for some innovative technologies starting with a 165mm cone that’s also constructed from LCP material, albeit slightly thicker to improve its Young’s modulus and afford it far greater strength. The diaphragm has been meticulously designed employing Klippel laboratory’s three separate speaker certification programs – DA- 2, PM-8 and KQC – in order to ensure absolute accuracy during its reciprocal movement. The surface has been coated with a thin protective layer and, despite the moving surface being extremely resilient to deformation, it still retains minimal mass remaining able to move with lucidity to behold. The cone is encircled by a strong but flexible surround which boasts a rounded EROM symmetry, although Rockford prefers to call it VAST – an acronymic for vertical attached surround technique.

Rather than consume large portions of cone area with a wider surround effectively reducing the moving piston’s area, the VAST design instead elevates further before rolling and coming back to marry up with the diaphragm edge. This effectively allows for the same excursion and control but doesn’t turn your 6.5-inch booming midrange into a 5.25-inch squealing one. As it’s effectively the top portion of the suspension, the surround remains firm but flexible, keeping the motor in strict alignment during operation. Complementing the suspension below is a flat rolled Nomex spider which is connected to the upper edge of the former. The suspension is most robust, returning an efficiency of 87.5dB while possessing a loaded resonance of 50Hz. To achieve the latter statistic Rockford opted for a motor design that allowed for maximum movement between the flux-points of the neodymium magnet structure, to the tune of it boasting a rather sizeable Xmax of 12.6mm despite the overall mounting depth remaining 71mm. The motor itself features a 38 mm aluminium former wrapped with a double layer voice coil boasting a power ability of 125 continuous and maximum of double that thanks to the extended plate. Cooling-wise Rockford hasn’t cut any corners.

It starts out with eight perimeter intake vents; four large and four small. These import air directly into the voice coil gap, and not just the outer edge either. The former has a plethora of transfer holes that allow the cool zephyr to flow down the inner walls of the former too. I note Rockford has omitted a pole vent, circumventing this by employing the laws of thermal dynamics. The magnet itself is wrapped with a large finned heat sink, ergo allowing heat to dissipate away from the source via radiation. All internals are held rigidly in place by a magnetically inert and acoustically transparent octuple spoke aluminium basket, powder coated in black and finished with a plastic screw terminal block.

CROSSING OVER
Just as the drivers may be the brawn of this operation, the T3652-X crossovers are the brains. Their 116mm square case is 35mm high and is constructed from shock-resistant black plastic with a clear window atop giving your eyeballs access to the internals. They’re bi-ampable, and able to accommodate a multitude of applications employing a combination of second and third order slopes at 3kHz; the low-pass being the 12dB while the high-pass is the 18dB. Logarithmically speaking the T3652-X employs Butterworth slopes which allow both drivers to blend together seamlessly. Further enhancing this ability is an incorporated on/off-axis switch. Adjacent is another switch, this one controlling the attenuation of the tweeter, settable on +2dB/0dB or -2dB. Peeking inside reveals quality capacitors and two air core inductors wrapped with 1mm and 0.5mm copper wire respectively, in addition to other components all securely attached to a thick circuit board with plenty of real estate afforded to cooling.

Installation proved anything but difficult, thanks largely to the midrange having flexible mounting points. More interesting however, is the mounting hardware supplied for the tweeter. Because in a day and age where companies try to skimp wherever they can, we often see as a result lame tweeter ‘cups’ that are, in actuality, just over-glorified clamps. This new system developed by Rockford and affectionately called ‘Discreet Dual Clamp’ (DDC), provides for an equally concentric clamping pressure around the perimeter of the mounting hole, meaning the tweeter can be locked in and sealed, literally. Other hardware is also included such as surface mount cups, screws, tools and two tidy looking mesh grilles.

With drivers worn in it was time to see how Rockford’s latest offering would fare against stiff competition in this price region. Initial impressions declare they’re not a bad speaker set, and upon this point many reviewers would box them again forthwith. However time was my ally; ergo I sat listening for many an hour, running through song after song I know inside out.

This is where things got interesting. When you start critically listening like this you often start finding flaws in the reproduction of many high-end speakers. I found the opposite occurred when listening to the T3652-S components. The longer I listened, the fonder I became. The tweeter produces the higher order frequencies cleanly enough, however you start to appreciate that it also reproduces all manner of little details that other component sets tend to miss. The midrange shares similar idiosyncrasies in that they’re happy to faithfully reproduce everything they’re asked to with impressive detail and minimal fuss, although in reality they’re less bass heavy than some other speakers. However that’s how Rockford designed them; they’re a component set designed to reproduce music with indubitable accuracy, not cave your head it. Linearity-wise they’re quite even and although not the absolutely epitome of smoothness it’s hard to argue with how Rockford has set the crossovers up. The Butterworth logarithm employed does wonders to mask the gap that’ll exist between the drivers in nearly all installations.

CONCLUSION
Truth be told, the T3652-S may possess certain limitations, but then they’re built to represent good value for money, not to consume it all. They’re still easily able to outperform many other speakers… many that, just between us, are significantly more expensive too.

 

Brand: ROCKFORD FOSGATE
Model: T3652-S
Reviewed at: $1099

+ Solid engineering, generous mounting hardware and great sound
– Nothing stands out

TYPE: 2-WAY COMPONENT SPEAKERS – 25mm tweeter and 165mm midrange
Power Handling: 125 watts continuous, 250 watts maximum
Frequency Response: 40Hz – 30kHz
Impedance: 4-ohms tweeter, 4-ohms midrange

Australian distributor: Directed Electronics Australia