Measurements Here are the measurements for the Concerta2 F36 speaker (click on each chart to view it in a larger window).
Frequency response On-axis: ±2.2 dB from 43 Hz to 10 kHz, ±2.9 dB to 20 kHz Average ±30° horiz: ±1.9 dB from 43 Hz to 10 kHz, ±2.8 dB to 20 kHz Average ±15° vert/horiz: ±1.7 dB from 43 Hz to 10 kHz, ±2.7 dB to 20 kHz
Impedance min. 3.7 ohms/158 Hz/-4.2°, nominal 6 ohms
Sensitivity (2.83 volts/1 meter, anechoic) 88.9 dB
The first chart shows the frequency response of the F36. The second chart shows the impedance. The computer that runs my LMS analyzer broke down as I was putting these measurements together, so I am temporarily unable to present charts with average responses. In the meantime, I've presented a chart showing the response at 0° on-axis and 10°, 20°, 30°, 45° and 60° off-axis. Ideally, the 0° curve should be more or less flat, and the others should look the same but should tilt down increasingly as the frequency increases.
The response plot of the F36 could be used to illustrate the ideal dispersion for a loudspeaker. Except for a roughly half-octave-wide dip in the treble, the on-axis plot is almost perfectly flat. As the microphone moves further off-axis, there's no crossover dip or anything like that, just an increasingly gradual treble roll off. Adding the grille produces dips of about -3 dB at 2.8, 5.8, and 11.7 kHz, which is pretty typical of fabric grille effects.
Sensitivity of the F36 is excellent at 88.9 dB (measured at one meter with a 2.83-volt signal, averaged from 300 Hz to 3 kHz), which means the F36 needs only about seven watts to hit 100 dB. And that's the anechoic sensitivity; you'll get perhaps an extra three dB in your listening room. Impedance averages about six ohms. Considering the excellent sensitivity, you can feel safe driving this speaker with practically any amp.
Here's how I did the measurements. I measured frequency response using an Audiomatica Clio FW 10 audio analyzer with the MIC-01 measurement microphone, and the speaker driven with an Outlaw Model 2200 amplifier. I used quasi-anechoic technique to remove the acoustical effects of surrounding objects. The speaker was placed atop a turntable that elevated it three inches off the ground. The mic was centered on the tweeter axis and placed at a distance of two meters from the front baffle and a pile of denim insulation was placed on the ground between the speaker and the mic to help absorb ground reflections and improve accuracy of the measurement at low frequencies. Bass response was measured by close-miking the woofers and ports, then scaling the port responses appropriately and adding that sum to the woofer responses. I spliced this result to the quasi-anechoic results at 220 Hz. Results were smoothed to 1/12th octave. I made measurements with the grille off except as noted. Post-processing was done using TrueRTA software.
The Downside The F36's treble sounds neutral--not boosted or rolled off--but it's exceptionally clear. This means if a recording is bad, the F36 will let you know it. I can't say the speakers highlighted the grating surface-noise effects added to parts of Freddie Joachim's "Shoulder Kiss," but they did nothing to cover up what to me is a regrettable aesthetic decision. I had to turn the system down about 10 decibels to tolerate this recording. A speaker with a soft-dome tweeter (and a soft-sounding soft dome at that) would probably sound more pleasing on recordings like this, or on Toto's somewhat bright-sounding Toto IV, but there's no way it would deliver the detail and sense of space that the F36 presents.
Comparison and Competition Using my Van Alstine AVA ABX switcher, I compared the F36 with the F206 and the $11,495/pair Monitor Audio PL200 II. (These are the speakers I happened to have around the house at the time.) Most of this test focused on A/B comparisons between the two Revels.
The F206 has a rep for being one of the most open-sounding (i.e., non-boxy) box speakers on the market, and here the F36 couldn't match it. The F206's mids and treble were about a notch or two clearer and more detailed. Even though I occasionally felt that the F36's bass could use a bit more oomph, its low end was far more satisfying that what the F206 could muster. "The F36 is less of an 'audio magnifying glass' than the F206, but it's often more fun to listen to," I wrote in my notes.
It seems that every big-name audiophile speaker company has a tower speaker around $2,000/pair, including the $1,999/pair GoldenEar Technology Triton Five, the $1,999/pair MartinLogan Motion 40, the $1,999/pair Monitor Audio Silver 8, and the $2,199 PSB Imagine T. I can't comment on the Motion 40 because I haven't heard it, but I have heard the rest, and they're all very good-sounding, very well-engineered speakers. I'm confident the F36 is at least a match for any of them, though. The Revel can also go toe to toe with the growing number of fantastic Internet-based speakers at the $2,000 range, such as the Tekton Pendragon, SVS Ultra Tower, and so on.
Conclusion Simply put, I think the F36 is today's best value I've heard in a midpriced tower speaker. There's no one to whom I wouldn't recommend it.