|Klipsch RF-5 Loudspeakers|
|Home Theater Loudspeakers Floorstanding Loudspeakers|
|Written by Tim Hart|
|Friday, 01 March 2002|
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In my early years of stereo, there were few brand speakers that were coveted as much as Klipsch. At that time in my life, I felt it was the best speaker on the planet for playing rock 'n' roll. Every time I heard them, I knew that I would have to figure out a way to own a pair. I managed to buy a new pair of the Heresys, which set me back a pretty penny, yet I was never disappointed with my purchase. When I found out that the new Klipsch RF-5’s were coming my way for review, I was excited to see how far Klipsch had come in the 20 years since I called them my reference speakers.
The RF-5 ($1,500 a pair) is second from the top of Klipsch's new Reference Series, with the RF-7 ($2,200 a pair) at the top of the heap. The RF-5 sports some of Klipsh's newer accoutrements, like their eight-inch Tractrix horn, the Cerametallic driver cone material and the cast-polymer woofer frames.
The RF-5 has an attractive two-way floor-standing design. The inch Tractrix horn is set above the two vertically arrayed eight-inch Cerametallic drivers in a rear-ported and internally braced MDF cabinet that measures 41.5 inches high, nine inches wide and 14 inches deep, weighing 60 pounds apiece. The frequency response is 34Hz-20kHz ±3dB, with a measured sensitivity of 99dB @ 1watt/1 meter. Power handling is 150 watts, 600 watts peak at eight ohms. The review pair came in black satin, but Klipsch also offers a maple or cherry finish at no additional cost.
Klipsch's design philosophy is to minimize distortion by maximizing sensitivity, and their horn design has been the hallmark of their loudspeakers since the 1940’s. The horn-driven speaker is a basically a flute-shaped rectangular tube where, in the case of the RF-5, it is coupled to a one-inch titanium dome compression tweeter. The compression tweeter increases the pressure of the sound wave to around 4:1, accelerating the sound through the smaller portion of the horn. This is where the efficiency of the Klipsch speakers originates. As the sound exits the larger portion of the horn, the rectangular shape is designed to control dispersion, 90 degrees in the vertical, and 60 degrees in the horizontal, which is said to minimize side wall interaction, one of the most offending situations that a speaker owner may confront. The eight-inch Tractrix horn uses a very large video-shielded 9.6-ounce magnet that actually fully encloses the rear portion of the motor, which provides more magnet surface area, as opposed to a hollow core magnet that surrounds the motor (the type found in my old Heresys). A hollow core magnet allows the motor to breathe, whereas in the case of the Tractrix horn, cooling is actually obtained through the spider assembly, so that surface area surrounding the motor is maximized. This is said to increase the speed and accuracy needed to produce the speakers' signature high-frequency presentation.
The two eight-inch Cerametallic bass drivers handle the lower octaves and utilize a motor assembly similar to the horn driver, with 28-ounce video-shielded magnets for horsepower. In the old days, Klipsch had enormous woofers to create the sound pressure levels that made them famous. But in today’s home environments, Klipsch recognizes that this approach is not size-practical. So Klipsch has to get more from less driver area. The cone material for these drivers is aluminum, which goes through an anodization process. Anodizing is basically is a process by which the aluminum surface is transformed into a thin layer of almost pure aluminum oxide, which is a ceramic, hence the Cerametallic. This adds stiffness to the material for less deformation during high excursion, as well as providing a protective and decorative coating, which adds to the RF-5’s classy look with the grills removed. Without question, the bass is better defined than what I remember hearing in my Heresy’s.
The cabinet’s rear port is larger than the customary size found on more traditional speakers. I was a bit concerned that a small animal might find refuge there, only to be rudely ejected when the music starts. However, there is a reason for the added scope, as the size is said to eliminate "chuffing" from the airflow, which can occur when air within the enclosure moves rapidly through too small a port.
The internal electronics consist of a crossover network that is a second order high-pass and fourth order low-pass arrangement, utilizing film capacitors and air core inductors, all wired with Z-Series Monster Cable wire from the terminal jumpers to the voice coil. The RF-5 has two sets of speaker terminals to bi-wire or bi-amp. Access to the terminals is adequate and will easily allow for spade lugs, bare wire, or banana jacks. It is pleasing to see that Klipsch uses the Monster cable as jumpers instead of gold-plated stamped sheet metal. Wire is a much better conductor.