Rogersound Labs CG4 5.1 Speaker System Reviewed

Rogersound Labs CG4 5.1 Speaker System Reviewed

Brent Butterworth reviews the Rogersound Labs CG4 speaker system. What did he think of this 5.1-channel home theater system that sells for $2,075? Read on to find out.

RSL-CG4.jpgI started reviewing home theater speaker systems in 1991, way back when there were only one or two companies making a dedicated center speaker. Since then, hundreds of systems have passed through my various listening rooms, at prices from $50 (yep) to well over $500,000 (really). They've appeared in countless configurations, from huge tower speakers to satellite speakers the size of golf balls. Of all of them, the ones I most often enjoy reviewing are the ones that employ medium-sized, two-way satellite speakers and a subwoofer in the 10- to 12-inch range. They're usually easy to set up, the speakers usually blend well with the subwoofer, and the modest size of the woofers in the satellites tends to give them broad dispersion and a big, spacious sound. One great example is the Rogersound CG4 5.1 system.

The CG4 system is based around four 10.5-inch-high CG4 satellite speakers, each one with a four-inch, polypropylene-cone midrange/woofer and a one-inch, silk-dome tweeter. The horizontal center speaker is the 16-inch-wide CG24, which has the same drivers as the CG4 with the addition of an extra mid-woofer. Both models use Rogersound's Compression Guide design, which divides up the interior of the speaker cabinet to reduce cabinet resonance and ports the woofer through a thin slot.

Rogersound's Speedwoofer 10 subwoofer provides the bottom end. It's unusual in a variety of ways; in fact, the only "ordinary" part is the 10-inch woofer. The woofer is driven by a 375-watt conventional Class AB amp, instead of a high-efficiency Class D, G, or H amp as in almost all modern subwoofers. Why? Simply because chief designer Howard Rodgers thinks Class AB sounds better. Many audiophiles do, too. Like the satellites, the Speedwoofer 10 employs the Compression Guide design.

What's most visually distinctive about the sub, though, is the controls, which reside in a little box that can sit atop the sub and attaches via a standard Ethernet cable. The box has knobs for volume and crossover frequency. There's nothing technically special about the box, but it does make it easier to adjust the sub. It also makes it possible to use the supplied wireless remote, which controls the same functions as the knobs and allows you to make your adjustments from different parts of the room. The remote and control box can communicate even when the sub itself is hidden. The back panel has line-level and speaker-level inputs and outputs, plus switches for phase and power.

The CG4 is Rogersound's least expensive home theater speaker system, at $2,075 for the whole schmear (with free shipping in the 48 states and a 30-day return policy). You can also add two more surrounds for 7.1-channel sound; substitute timbre-matched in-wall and in-ceiling speakers for the left, right, or surround channels; and add one or more extra subs. All of the components are also available separately.

The Hookup
Setup of the CG4 system is about as easy as it gets with a 5.1 system. Put the little satellites on some stands, put the center speaker below your TV (or, if you have a projector as I do, on its own stand), and put the subwoofer wherever it sounds the best. In my case, that's in my "subwoofer sweet spot," a position along the front wall about four feet to the right of center. That's not necessarily what will sound best in your room, though. (If you want to find your room's "subwoofer sweet spot," put your subwoofer in your listening seat; put on a tune with a melodic, wide-ranging bass line; then crawl along the walls in the front half of the room to find the spot where the bass line sounds the most even.)

I used my Denon AVR-2809ci AV receiver only as a preamp/processor and used an AudioControl savoy seven-channel amp to power the speakers. I used the line input on the Speedwoofer 10 and set the crossover frequency on the sub as high as it would go (170 Hz). The four-inch woofers in the satellites and center speaker aren't bass monsters, so I set the subwoofer crossover point to 100 Hz to take some load off the little guys. This proved especially important with these speakers. With the industry-standard 80-Hz crossover point, a "sonic hole" opens up between the sub and the satellites/center, which makes voices sound somewhat thin and trebly.

I tried the sats and center with the metal grilles on and off (they are held strongly in place by neo magnets), and I decided to keep them on; they look better and arguably sound just as good with the grilles.

Guessing that this particular Rogersound 5.1 system would primarily attract the interest of home theater fans rather than audiophiles, I concentrated much of my audition on movie soundtracks.

One of my favorite tests to find out fast what a home theater speaker system can do is to play chapters three and four of Star Wars-Episode II: Attack of the Clones. This selection starts with super-deep bass tones portraying several flyovers of a spaceship; it proceeds into a high-volume explosion of that spaceship that's packed with subtle Foley effects; and then it moves into a scene in an office where various characters talk and music swells in the background.

What caught my ear first was the way the Speedwoofer 10 handled the spaceship flyovers. It really seemed to grab hold of my listening room the way a big super-subwoofer like the Hsu Research VTF-15H Mk2 does; I felt an awesome, slightly frightening shake in my chair. For a 10-inch subwoofer, this is excellent performance. It handled the explosion easily, giving me that same scary, edge-of-the-seat experience. When the drama moved to the Chancellor's office, I noticed that the conversation sounded extremely clear, no matter who was speaking. And the ominous low-frequency tones that run underneath the dialogue were easy to hear; with some small systems, they're mostly lost.

I didn't adjust the volume when I switched to the "Thanator Chase" chapter from Avatar. Unfortunately, the Panasonic Blu-ray player remembered the place I'd left off last time I watched this scene, and it started from there with the system volume cranked. The system jumped right into the chase instantly without even a hint of distortion--and, in the process, made me jump out of my chair. After I got the volume down a few dB and started the chapter over again, I noticed that the system had terrific imaging between the front and side speakers and that the relatively small surrounds had no problem handling the unusually loud and dynamic surround-channel content in this scene.

Longer-term movie watching, including VUDU streams of Moneyball and Dawn of the Planet of the Apes, showed that the CG4 system can deliver awesome dynamics for its size while also creating a compelling sense of ambience and delivering dialogue with outstanding clarity and natural timbre. It was hard for me to accept that this system cost just $2,000; it sounded to me like a much larger system, yet it had the smooth midwoofer/tweeter blend you usually get by using a small four-inch driver.

When I switched over to stereo music, I got very good (although perhaps not as shockingly outstanding) results. Steely Dan's "Aja," an audiophile classic, sounded about 90 percent as good as it gets. The tune's bass line sounded extremely melodic and tight, and the tune had the big, spacious sound it should have. Imaging of all the instruments sounded precisely placed and natural. My notes for the live version of James Taylor's "Shower the People" said almost exactly the same thing, with the addition of the phrase "really digging this subwoofer!"

Click over to Page Two for Measurements, The Downside, Comparison & Competition, and Conclusion...

Here are the measurements for the Rogersound CG4 speaker system. Click on each photo to view the graph in a larger image.


Frequency response
Satellite: ±2.4 dB from 37 Hz to 20 kHz on-axis, ±2.7 average 0° to ±30°
Center: ±3.3 dB from 37 Hz to 20 kHz, ±4.8 average 0° to ±30°
Subwoofer: ±3.0 dB from 29 to 126 Hz

Satellite: minimum 6.6 ohms/100 Hz/+28°, nominal eight ohms
Center: minimum 4.4 ohms/100 Hz/+11°, nominal five ohms

Sensitivity (2.83 volts/one meter, anechoic)
Satellite: 84.1 dB
Center: 86.7 dB

Subwoofer crossover low-pass roll-off
-18 dB/octave

Subwoofer CEA-2010 maximum output
The first number is CEA-2010A (1M peak); the second is traditional (2M RMS):
40-63 Hz avg: 119.2 dB, 110.2 dB
63 Hz: 120.1 dB L, 111.1 dB L
50 Hz: 120.1 dB L, 111.1 dB L
40 Hz: 117.0 dB L, 108.0 dB L
20-31.5 Hz avg: 108.6 dB, 99.6 dB
31.5 Hz: 113.7 dB L, 104.7 dB L
25 Hz: 107.1 dB, 98.1 dB
20 Hz: 99.7 dB, 90.7 dB

The first chart shows the frequency response of the various speakers in the system; the second shows the impedance of the satellite and center speaker. (Impedance of the subwoofer driver is irrelevant; because it's internally powered, there's no reason to be concerned about impedance.) For frequency response, two measurements each for sat and center are shown: at 0° on-axis (blue trace for sat, purple trace for center) and an average of responses at 0°, ±10°, ±20° and ±30° (green trace for sat, orange trace for center), all measured on the horizontal axis. The center speaker's curves are scaled down -10 dB for display purposes. The subwoofer's ground plane response is shown in red.

The CG4 satellite measures beautifully, with a slight emphasis at 1 kHz and a very mild treble roll-off. Its off-axis response is very smooth, close to the on-axis response. The center speaker is smooth on-axis, where its measurement is quite similar to the satellite's, but the averaged response shows a fairly deep but broad dip centered at 2.5 kHz. This is the result of the two-way horizontal design; the two woofers are interfering with each other at this frequency, and the shallow first-order (-6 dB/octave) crossover in the center speaker makes the effect worse.

These measurements were done without grilles, but I also ran an on-axis measurement with the grilles. The metal grilles had a surprisingly small effect on the measured response, causing response variations of just ±1.1 dB between 3 and 10 kHz.

Sensitivity of the speakers, measured quasi-anechoically from 300 Hz to 3 kHz, is 84.1 and 86.7 dB, for the sat and center respectively. Figure about +3 dB more output in-room, which means you'll need about 40 and 20 watts, respectively, to hit 100 dB SPL. Nominal impedance is five ohms for the center and eight ohms for the satellite. (Both actually drop a little lower at 20 Hz--6.5 ohms for the sat and 3.3 ohms for the center--but that's outside their operating range.) I expect you could get loud levels with these speakers from pretty much any A/V receiver.

Here's how I did the measurements. I measured frequency responses 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 speakers sat atop a two-meter-high stand. The mic was placed at a distance of one meter, and a pile of attic 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 using ground-plane technique, with the microphone placed on the ground two meters from the speaker. I also close-miked the woofers and ports and summed that result for comparison with the ground-plane result. Bass response results were spliced to the quasi-anechoic curves at 240 Hz. Results were smoothed to 1/12th octave. Post-processing was done using LinearX LMS analyzer software.

I did CEA-2010A measurements using an Earthworks M30 measurement microphone, an M-Audio Mobile Pre USB interface, and the CEA-2010 measurement software running on the Wavemetric Igor Pro scientific software package. I took these measurements at two meters peak output, then scaled them up to one-meter equivalent per CEA-2010A reporting requirements. The two sets of measurements I have presented here--CEA-2010A and traditional method--are functionally identical, but the traditional measurement employed by most audio websites and many manufacturers reports results at two-meter RMS equivalent, which is -9 dB lower than CEA-2010A. An L next to the result indicates that the output was dictated by the subwoofer's internal circuitry (i.e., limiter) and not by exceeding the CEA-2010A distortion thresholds. Averages are calculated in pascals. Note that when I did the measurements at 25 and 20 Hz, I heard considerable port noise from the subwoofer.

RSL-CG4-Without-Grille.jpgThe Downside
Overall, I was extremely impressed with this modestly sized system. However, like all modestly sized systems, it does have some weaknesses, although they're minor.

The slot on the front of the subwoofer blows a hellacious wind on the low notes; I kept feeling its breeze on my feet. However, I only heard actual port noise in one instance, for about one second during one of the starship flyovers in Star Wars- Episode II. The sub refused to play the fundamentals of the ultra-deep tones in the recording of the Saint-Säens "Organ Symphony" from the Boston Audio Society Test CD, but the only 10-inch subs I've heard that can do so are the passive-radiator models with 1,000-watt digital amps.

Although I got a wonderfully spacious sound, the tweeter didn't deliver that charming, lush treble I get from my Revel F206 reference speakers, or many of the best audiophile speakers. But I can't recall many, if any, speakers in the CG4 satellite's price range (it's $500/pair, sold separately) that do have a treble I'd describe as lush/natural/effortless. Maybe the Music Hall Marimba.

In certain snippets of some movie soundtracks, the dialogue sounded slightly bright. With some music, the vocals sounded a little bright; with other music, they sounded a little soft. This led me to guess that there's some mild unevenness in the upper midrange/lower treble (see measurements above).

Comparison and Competition
There are just so many competitors out there that I'll cite only a few that I can talk about with some authority, and I'll break it out separately between the sub and the sats/center.

For the Speedwoofer 10's $750 price, you can actually buy a good 12-inch sub, such as the $639 Outlaw Ultra-X12 or the $619 Hsu Research VTF-3 Mk4. Both of those subs are larger and offer more output and deeper bass extension. However, I really like the tight 'n' tuneful character of the Speedwoofer 10's bass, and its compact size and attractive hand-painted gloss black finish will gain it entry into some living rooms where the comparatively less presentable Outlaw and Hsu subs might be banned.

Here are some other $500/pair options for satellites (citing only models that have matching horizontal center speakers). The SVS Prime Bookshelf is $498/pair, and it has a larger 6.5-inch woofer. I have only tested the Prime Tower (review to come); my educated guess is the Bookshelf's bigger woofer will let it play even louder than the CG4, but it probably doesn't sound quite as open and spacious at the CG4. NHT's Absolute Zero and PSB's Imagine B also run $498/pair. Both have a 5.25-inch woofer, so they sort of split the difference between the Prime Bookshelf and the CG4. However, their matching center speakers are relatively pricey, at $449 and $399 respectively, compared with $325 for the CG24 (and less, if you buy the CG4 package deal). Here it's a tough call, especially against the PSBs. I really like the CG4. I really like the PSBs. I guess it boils down to a personal/emotional decision.

I'm amazed and thrilled that someone can offer such a good home theater speaker system for just a little more than $2,000. The CG4 sounds very natural, plays very loud, and presents no weird quirks or setup difficulties. Can you do as well as the CG4 for this price? Maybe. Can you do better? Not with anything I've heard.

Additional Resources
• Visit our Bookshelf Speakers category page for similar reviews.
• Visit our Subwoofers category page for similar reviews.
• Check out the Rogersound Labs website to see the company's complete line of home theater and stereo speaker systems.

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