The RF-15's vinyl-wrap, cherrywood finish is pleasant enough but not terribly convincing; the other option is black ash. The sturdily constructed medium-density-fiberboard speaker stands 36.9 inches tall and weighs 37 pounds. All in all, the design is rather attractive and modern-looking.
Only 6.75 inches wide, the tower would be considerably precarious if it weren't for the molded-plastic stabilizers extending from the speaker's base. Klipsch includes spikes for carpets and rubber bumpers for hardwood or tiled floors.
The grille stays in place with magnets rather than iffy plastic pins. We expect that level of design detail on only high-end models, so it was a nice surprise on such an affordable tower.
The RF-15's titanium 1-inch tweeter is rather unusual. It sits in the mouth of a square Tractrix horn, which increases efficiency so dramatically that the loudspeaker can produce more volume per watt than conventional direct-radiating tweeters. The horn also controls the tweeter's dispersion, minimizing floor and ceiling reflections for sharper and more-exacting stereo imaging.
The tower's twin copper-colored, magnetically shielded 5.25-inch woofers are Cerametallic: the aluminum-anodizing process converts the cones' surface to ceramic. The idea is that the rigid Cerametallic cone won't flex or resonate, thereby making the sound cleaner and more accurate than that of conventional plastic or all-metal woofers. A flared rear port provides additional bass output. All of the RF-15's internal wiring is Monster cable.
Speaker specifications don't usually tell you much about sound quality, but we do rely on the sensitivity rating. If it's greater than 90dB, the speaker is ideal for use with low-power receivers. With its 96dB rating, the RF-15 can kick butt with as little as 50 watts. Moreover, it can handle upward of 100 watts continuously and a peak power of 400 watts.
The speaker's backside has two pairs of heavy-duty binding posts: one for the tweeter and another for the woofers. The design lets you "bi-wire" your RF-15s to eke out slightly better sound. Your other option is to stick with one standard cable.
Our opinions of the RF-15 evolved as we logged more and more time with it. At first, it struck us as pretty insubstantial and midrange-centric, but after 50 hours of use, it mellowed out a bit. We always heard good detail, but blues great Muddy Waters and other artists with powerful voices never sounded quite big enough. Female voices were sometimes too thin. On the upside, as with other Klipsch speakers we've auditioned, freewheeling dynamics made for rather lively sonics.
We noted a little extra warmth in the upper bass region, but in our room, bass was over and out by the time our test tones reached 50Hz. Most floor-standing speakers in this price class can reach down to the mid-40Hz range. Then again, that's what subwoofers are for, so we relied on Klipsch's RW-8 to flesh out the low end.
As tall as the RF-15 is, we found its imaging height extraordinary. Our pair produced life-size instruments and voices--a feat never equaled by even the better satellites we've heard. When we matched the towers with Klipsch's RC-25 center speaker, the sound moved seamlessly across all three front speakers. The matching little RS-25 surrounds projected a huge, wraparound sound field but blended well with the RF-15s.
We thoroughly enjoyed the RF-15s' performance on Confidence, a no-frills heist DVD that serves up a beat-heavy soundtrack, snappy dialogue, lots of gunplay, and gritty atmosphere. We kicked the volume a few notches higher than usual, and the RF-15s took it all in stride.
The RF-15's sound has an undeniable immediacy, but its treble wasn't as clean as we would have liked. Comparing the speaker with Infinity's entry-level floor-stander, the Primus 360, put the RF-15's strengths and weaknesses in perspective. The Klipsch was more vivid, but the big Infinity tower gave us a beefier low end, a slightly richer midrange, and a much sweeter treble. The two designs will appeal to very different tastes: the Infinity's sound is laid-back, while the Klipsch's is leaner, with greater detail. Just don't match your RF-15s with a bright-sounding receiver.