Originally Posted by AcuDefTechGuy
Originally Posted by Skylinestar
I've read many websites saying that MTM arrangement for center channel is bad. How's KEF Q200c and Q600c fare in this matter?
Here is one case where the Center measured better (5-point avg) than the L/R:
KEF R300 $900 each: +1.03/-3.07dB 200Hz-10kHz
KEF R600C $1,500 each: +0.84/-2.49dB 200Hz-10kHz
Let's drill down a little bit more into their measurements. After all, ± spec of a smoothed measurement is only useful if it's really abhorrent. Consider a speaker that with a smoothed response that fits in a 5dB window but is all over the window, and one that fits within the same 5dB window, but does so because the FR smoothly falls throughout that window.
Far more important than the window into which a sound power curve fits is the shape of the curve, and its smoothness. The former captures the speaker's voicing. The latter captures problems with the crossover design, resonances in the drivers, diffraction issues, etc. Obviously, these graphs don't capture the performance of the speaker as well as, say, a design-axis FR coupled with a polar map would and some compression sweeps would. But those smoothed measurements are useful for separating the "may be good, worth a listen to find out" speakers from the "wow, those suck" speakers.
The R300 looks very clean. KEF made a voicing choice to make the speaker sound "warmer" by bumping up the midrange. That's an editorial choice, not a flaw. Clearly, it works on some listeners, given that the R300 is routinely described as "warm" or "lush" sounding in show reports. Indeed, that midrange-heavy voicing seems to be the way top-tier British-heritage loudspeaker firms seem to believe small speakers should sound. The KEF LS50 measures similarly. The Tannoy Revolution DC4 and DC6 bookshelf are also so voiced.
True, KEF's voicing choice here means that someone more interested in accuracy than euphony would be better served by the Q900 than the R300!
The R600c is voiced rather differently from the R300, with a smoothly declining response with frequency. (That is my preferred voicing for a wide-directivity speaker, unless the room is very large. Then I prefer a voicing that's flatter - along with a lot more radiating area.) While HTMag lists the R600c's response window to be very tight as is (~3.5 dB), the graph (at that level of smoothing, at least) reveals deviation from the downwards-sloping target curve
to be damn near zero: a small and narrow dip at 1kHz, and a small dip+bump from 4-7 kHz. Absolutely stupendous performance by any standard, though I bet it would have come out even cleaner had KEF used a cabinet designed to minimize diffraction rather than those nasty sharp edges. The bass extension is a bit light, but IMO still fine if one uses a good multisub system under them. I like the compromise of small size, higher-than-average efficiency, and limited bass extension for mains in a modern system.
Also, based on these measurements, anyone who thinks the R600C is a "sonic match" for the R300 is deaf. Just imagine an oboe player walking across the front of the room. Any reasonably critical listener will easily hear that variance in voicing. So these graphs further prove that there are two types of front speaker setups: identical speakers in all three positions, and flawed.
Still, a front stage based on three R600c's may be just the thing for many! (For multichannel music; basically anything that gets loud enough and has a clear enough midrange will do for adding sound to moving pictures.) And at just ~$3k for a trio, the R600c seems quite a strong value. (Yes, I would certainly use three properly identical speakers up front, rather than settling for the flawed approach of two R-Series towers and a horizontal center channel, even if the bigger R-series are voiced more like the R600c than the R300.) They're basically the next step up from the Q900, in everything but the bass at least. A trio of R600c's would be attractive for those who can't fit three Q900's in their living room, who can't/won't do the re-engineering required on the Q900 to tame its woofer breakup, or who find the build quality on the Q-series unacceptable for their living rooms. Hell, if my local KEF dealer weren't a feckless tool, I would consider going down and seeing if there's anything that would preclude me picking up a trio of them. Then again, if my local KEF dealer weren't a feckless tool, I would've also bought three Q900's from him, so I guess I wouldn't be in the market.