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RSL CG5 and CG25 Speakers Measurements and Conclusion

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CG5 outdoor testing2.jpg  CG25 outdoor testing2.jpg

The RSL CG5 and CG25 speakers were measured in free-air at a height of 7.5 feet at a 1-meter distance from the microphone, and the measurements were gated at an 11-millisecond delay. In this time window, some resolution is lost below 250 Hz and accuracy is completely lost below 110 Hz. Measurements have been smoothed at a 1/12 octave resolution. The CG5’s ‘Tweeter Adjust’ knob is set to ‘Ref’ for all following tests unless stated otherwise. The CG25 measurements reference an upright, vertical orientation unless stated otherwise. 

cg5 Spin-O-Rama.jpg   cg25 Spin-O-Rama.jpg

The above graph shows the direct-axis frequency response and other curves that describe the speakers’ amplitude response in a number of ways. For more information about the meaning of these curves, please refer to our article Understanding Loudspeaker Measurements Part 1. The CG25 measurements are referenced to it standing upright in a vertical orientation; if these graphs were referencing it in a horizontal orientation, there would be differences although not major ones. The curves presented here are not textbook flat responses, but for those who know how to correlate measured responses to sound quality, there is a lot to like here despite some visible flaws. The most prominent feature here is the elevated bass and lower midrange which seems to drop abruptly just after 1 kHz. That does color the sound, indeed in my listening I did hear what I thought to be a bit extra mid-bass, but the overall effect is more like lending the speakers a warmer sound character, especially since the midrange and treble is relatively neutral, or, in the case of the CG25s, slightly depressed upper treble above 10 kHz. If I had to guess, I would say that the high Q bump centered around 800 Hz is a pipe resonance from the unusual ported design that RSL has utilized. One thing to note is the outstanding listening window curve on the CG5s above 1 kHz; that is about as neutral as a speaker can measure. The CG25 also has a good listening window curve in that region although not quite as picture-perfect. The crossover circuit seems to be very well conceived since there is very little evidence of it in these graphs; crossovers circuits are the kind of component that is invisible and imperceptible when they are working correctly. The bottom line in these graphs, we see that the CG5 and CG25 speakers are a bit weighted towards bass but otherwise fairly evenly voiced.  

 cg5 horizontal waterfall response 3D.jpg   cg25 horizontal waterfall response 3D.jpg

cg5 horizontal waterfall response 2D.jpg    cg25 horizontal waterfall response 2D.jpg

The above graphs depict the speaker’s lateral responses out to 100 degrees in five-degree increments. More information about how to interpret these graphs can be read in this article: Understanding Loudspeaker Review Measurements Part II. In these graphs, we get a more detailed look at the story told by the ‘spin-o-rama’ graphs: smooth mids and treble, elevated bass, and a bump centered around 800 Hz or so. The elevated bass and lower midrange bump are features that many room correction programs such as Audyssey would likely smooth out to an extent for those who want those features reduced. I would say that reducing those features with automated room correction may not be worth the risk of all the other damage these systems tend to cause when doing fullrange correction. One thing we can see from these graphs is that directivity is fairly uniform across angles, so these speakers can be manually EQ’d with predictable results, unlike speakers that have non-matching responses at different angles. These graphs also tell us that the most balanced sound occurs on-axis, so I would say that the optimal toe-in angle for these speakers will have them facing the listener directly, since the sound doesn’t change much at all as far off-axis as 30 degrees.

 cg5 polar map.jpg   cg25 polar map vertical orientation.jpg

The above polar map graphs show the same information that the preceding graphs do but depict it in a way that can offer new insight regarding these speakers’ behavior. Instead of using individual raised lines to illustrate amplitude, these polar maps use color to portray amplitude, and this allows the use of a purely angle/frequency axis perspective. The advantage of these graphs is they can let us see broader trends of the speaker’s behavior more easily. For more information about the meaning of these graphs, we again refer the reader to Understanding Loudspeaker Review Measurements Part II.

From these graphs, we can see that the CG5 and CG25 speakers have a very wide horizontal dispersion with a wide and consistent spread response out to 70-degrees off-axis. These speakers will have a wide angle of coverage for those who have a broad listening area. It’s all the better that they have a uniform off-axis response since listeners will hear much reflected, off-axis sound from such a wide dispersion pattern. A few features we see is that there is some slight waist-banding around 1 kHz, but it is not severe. As we see for so many 1-inch dome tweeters, the CG5 and especially the CG25 start to beam above 10 kHz. This is not a big deal, but those who want to be in an area of high treble coverage should listen within a 30-degrees of the on-axis angle. That is still a pretty wide angle so most listeners should get hit with a full range of sound. If the user wants a warmer sound, they can simply angle the speakers so that the listening position is at a 30+ degree angle from the direct front-facing direction of the speaker. This will shear off the output above 10 kHz and make the sound warmer; while I wouldn’t characterize these speakers as ‘bright,’ this trick might be useful for those who are more sensitive to high frequencies.  

cg25 polar map horizontal orientation.jpg 

The above map shows the CG25’s lateral behavior when it is lying flat in a horizontal orientation like how center speakers are usually positioned. While this may seem like odd behavior, it is actually quite typical for MTM speakers when they are used horizontally. Most center speakers produce a similar lateral response, and it happens because the woofers are reproducing the same signal but at different distances from the microphone as it moves further off-axis. The sound waves from the woofers lose phase alignment at off-axis angles and start to cancel out each other’s respective output. The sound stays consistent out to a 20-degree angle, but past that, cancellation begins to take a toll on the response. When the CG25 is laid flat as with most center speakers, it should be listened to within 20-degrees of the on-axis angle. While the irregularities of these cancellation patterns can average out by the various acoustic reflections that ultimately combine at the listening position, there will still be lessened amplitude overall for that frequency band. In other words, the audibility of the in-room effects of lobing will not likely be as stark as what is seen on this graph, although it still may be perceived as a reduction in midrange energy when compared to its upright orientation. 

Of course, the lateral behavior of a speaker that is placed horizontally will become its vertical behavior when that speaker is positioned upright, so this graph also shows the CG25’s vertical dispersion when it is standing on end. That doesn’t change the fact that the best response occurs within 20-degrees of the on-axis angle, but that is very likely going to be within the listening position if the speaker is placed anywhere around an ear-level height. 

cg5 vertical waterfall response 3D 2.jpg 

The above graph shows the CG5’s speaker’s response behavior along its vertical axis where zero degrees is directly in front of the tweeter, negative degree values are below the tweeter, and positive degree values are above the tweeter. Since RSL’s literature shows the speaker oriented with the woofer above the tweeter so much, I should specify that negative value angles on this graph mean that the woofer is situated below the tweeter, and positive value angles are, of course, on the non-woofer side of the tweeter. This is an important distinction to make here because of the substantial asymmetry we see on this graph. Normally, what is seen with two-way bookshelf speakers of this type is that one side of the vertical axis is slightly better behaved than the other or that they are about the same, but there isn’t normally a wide angle on the vertical axis that holds a great response, so listening should be done with the speaker level at the same height with the ears. That is not the case with the CG5 speakers- it has a wide vertical angle where there is a good response, but it only occurs on one side of the vertical axis. Let’s take a closer look:

CG5 woofer side vertical responses.jpg  CG5 tweeter side vertical responses.jpg

The left graph shows the vertical responses of the CG5 as we move off axis at a 10, 20, and 30-degree angle towards the woofer end of the speaker. The yellow curve is the 10-degree angle, and it isn’t all that bad, but a very substantial null develops very quickly past 10 degrees which takes a large bite out of the sound. This null is very audible. On the other side of the speaker (shown in the graph to the right), the tweeter half, the response stays very even out to 30-degrees with not much change. So one half of the vertical axis is abnormally good, but the other half is abnormally bad. What this tells us is that the CG5 should be listened to either on-axis where the listener’s ear is level with the tweeter or in the hemisphere of coverage of the tweeter’s half of the speaker. This is an unusual feature but it can be very advantageous in getting a great sound at the listening position in circumstances where the speaker cannot be placed at ear level. This can be useful in situations where the bookshelf speaker stand is either too tall or too short or where the speaker has to be placed on shelving that is higher or lower than the ear level of the listening position. These are very common scenarios. Many other bookshelf speakers would need to be tilted on some kind of angled riser to face the listener in order to achieve a good sound, but with the CG5 speakers, it only needs to be placed on the end where the listener is within the tweeter’s half of the hemisphere of the CG5. This gives the CG5 placement flexibility that most other bookshelf speakers do not possess.

CG5 and CG25 low frequency responses.jpg 

The above graph shows the CG5 and CG25’s low-frequency responses that I captured using groundplane measurements (where the speaker and microphone are on the ground in a wide-open area). RSL claims a +/-3 dB window of 54 Hz for the CG5 and 51 Hz for the CG25. That seems about right, although the measured CG25 response would seem to stretch that window a bit. The port tuning frequency for both speakers looks to be around 50 Hz. The bass response itself is smooth and nicely linear, although, as we saw from previous graphs, it is a bit elevated with respect to the rest of the frequency range. The CG25s look to have a slightly higher ratio of mid-bass to deep bass which is what was heard in my own listening of the speakers.

cg5 tweeter adjust effects2.jpg

For those who are curious, the above graph is the measured differences made by the ‘Tweeter Adjust’ knob on the CG5, with the green curve representing the ‘Ref’ setting, the red curve representing the ‘Low’ setting, and the blue curve representing the ‘High’ setting. The differences are there, but they aren’t enormous. In my listening, I found the differences to be subtle.

cg5 impedance.jpg  cg25 impedance.jpg

The above graphs show the electrical behavior of the CG5 and CG25 speakers. RSL does not list a spec for the impedance, and they only have a ‘recommended impedance setting’ spec for “6 or 8 ohms (whichever is higher),” referring to AVR’s that have an impedance selector. I would characterize these responses as 6 ohms at the worst, but the load is relatively benign overall. These speakers are not a hard load for most amplifiers. The impedance minima occur at about 200 Hz on both speakers where it dips just below 6 ohms. There is nothing surprising or unusual about the responses shown here, and these are very typical for speakers of this type. The only thing to note is how much alike the CG5 and CG25 are, even though the CG25 has an additional woofer. If the CG25 woofers were wired in parallel, one would expect to see a halving of impedance compared to the CG5, but if they were wired in series, the impedance value would double. RSL manages to have both speakers have nearly the same impedance by using bass drivers in the CG25 that has double the impedance of the bass driver in the CG5 and then wiring the two CG25 drivers in parallel. RSL Speakers did this because they wanted both speakers to have the same electrical characteristics. I measured the sensitivity of the CG5 at 85.7 dB and the CG25 at 88.5 dB for 2.83v at one meter. Those values are very close to the specs given by RSL and are pretty normal for speakers of this type.

Conclusion

Before bringing this rCG25 pair close.jpgeview to a close, I will briefly go over the strengths and weaknesses of the products under review as I always do, and, as usual, I will start with the weaknesses. A discussion of the CG5 and CG25’s weaknesses is bound to be short because they don’t have many. Pretty much the only shortcoming that I would say they have is that the mid-bass region is somewhat elevated in comparison to the rest of the frequency range, and this does steer the sound away from being a completely neutral speaker. This quality does lend the speaker a warmer sound overall, and, to be honest, this type of voicing doesn’t bother me. If I had to choose, I would much prefer the sound to be weighted toward the low end than the high end. This makes the RSL CG5 and CG25 speakers easy to listen to, if not totally accurate. As I said before, this flaw is so benign that I don’t even think it’s worth running room correction equalizers like Audyssey to correct it. The speakers sound good in spite of this overall tilt in their response, so why risk messing that up?

The RSL speakers could project a wide yet precise soundstage, and I found their imaging abilities to be superb.

That brings us to the first point in our discussion of the CG5 and CG25’s positive attributes, and that is their sound quality. Even with that extra bass, I thought these speakers sounded very nice. The measurements support my experience as well, with excellent performance above 1 kHz. Sometimes when speakers have extra bass, they can sound a bit ‘thick,’ but I didn’t find this to be the case with the CG5 and CG25 speakers. I never had any trouble with dialogue intelligibility, and musical instruments didn’t sound tonally unbalanced. I enjoyed everything that I listened to on the CG5 and CG25 speakers. They could project a wide yet precise soundstage, and I found their imaging abilities to be superb. They had a very good dynamic range for their class type as well, especially the CG25s. They could stay unexpectedly clean at loud levels. Furthermore, their wide and even dispersion given allows for even coverage over a broad listening area. And, as discussed before, their vertical response on the tweeter half of the speaker makes them a great choice for situations that do not allow for typical speaker placement heights. On top of their aural performance is their electrical behavior which makes them suitable for nearly any amplifier.  

Outside of their sound performance, the CGCG5 pair5.jpg5 and CG25 look more stylish than normal bookshelf speakers and MTM monitors. Not many speakers in this price class have gloss finishes, but these do. The white finish gives these CG5 and CG25 more flare than you normally see in this class of speaker, but those who prefer a more restrained aesthetic can always choose the black finish. On top of their looks is their build quality; the CG5 and CG25 are not the cheapest bookshelf speakers out there, but it’s clear the money went into good components and design rather than an upcharge for a brand name.

Something else in their favor is RSL’s excellent customer service. If a customer ever has a problem or a question, RSL will address the issue promptly, so anyone looking to order from them can have confidence that they will be taken care of. RSL has a loyal customer base due to their good customer service and also high-value products, and those RSL fans who are contemplating an upgrade to the ‘5’ series would be doing themselves a favor by giving these higher-end speakers a chance. I did have some listening experience with RSL’s CG23 speakers and feel that the CG5 and CG25 are substantially better performers. That isn’t surprising since they are more expensive, but I thought that the lower frequency range on the CG5 and CG25 was much smoother and that the overall sound was more laid back.

CG25 outdoors.jpgAt this point, I am sure it is clear to readers that I liked the CG5 and CG25 speakers and find them to be an easy recommend for bookshelf speaker shoppers in this price range. There are lots of good bookshelf speakers in this price range, but there is always room for more well-engineered, great-sounding speakers. The CG5 and CG25 are a welcome competitor to the market for consumers. Those who are curious can demo these speakers in their home risk-free since RSL allows a 30-day in-home trial that is risk-free since RSL covers shipping both ways. If the buyer does not wish to keep the speakers for any reason, they can return them free of charge. While that might be a risky policy for many speaker manufacturers, I think it is a safe choice for RSL since I doubt they will see many returns of the CG5s or CG25s. 

The Score Card

The scoring below is based on each piece of equipment doing the duty it is designed for. The numbers are weighed heavily with respect to the individual cost of each unit, thus giving a rating roughly equal to:

Performance × Price Factor/Value = Rating

Audioholics.com note: The ratings indicated below are based on subjective listening and objective testing of the product in question. The rating scale is based on performance/value ratio. If you notice better performing products in future reviews that have lower numbers in certain areas, be aware that the value factor is most likely the culprit. Other Audioholics reviewers may rate products solely based on performance, and each reviewer has his/her own system for ratings.

Audioholics Rating Scale

  • StarStarStarStarStar — Excellent
  • StarStarStarStar — Very Good
  • StarStarStar — Good
  • StarStar — Fair
  • Star — Poor
MetricRating
Build QualityStarStarStarStar
AppearanceStarStarStarStar
Treble ExtensionStarStarStarStarStar
Treble SmoothnessStarStarStarStarStar
Midrange AccuracyStarStarStar
Bass ExtensionStarStarStarStar
Bass AccuracyStarStarStar
ImagingStarStarStarStarStar
Dynamic RangeStarStarStarStarStar
Fit and FinishStarStarStarStar
PerformanceStarStarStarStarhalf-star
ValueStarStarStarStarhalf-star
About the author:

James Larson is Audioholics' primary loudspeaker and subwoofer reviewer on account of his deep knowledge of loudspeaker functioning and performance and also his overall enthusiasm toward moving the state of audio science forward.

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Recent Forum Posts:

shadyJ posts on July 18, 2020 23:50
zxlankyxz, post: 1405050, member: 92310
I am really like what I am hearing about these RSLs and they look great. I am leaning toward 3x CG25s for the fronts and I am debating about CG3s or CG5s for the surrounds in a 5.1.4. I will be using the C34Es for the 4 ceiling speakers. I would be using this system for watching movies, gaming and also listening to music. I would imagine that for movies there wouldn't be as big of a difference what I pick for surrounds. I am guessing that there would be a larger difference for music though? It's a decent price jump from the CG3 to the CG5, but I would do it if it's worth the performance jump. Attached is a proposed (this is for a basement that we will be finishing) layout for the area. I would likely have to mount them directly on the wall, about 3 feet above ear level and at 90 degrees to the couch with primary listeners on it. It's a large space that is open on all sides, so my primary concern is making sure that the system will fill out the space and sound as good as possible.

38067
I would go for the CG5s as surrounds, and I would mound them such that the tweeter is below the woofer, and the listener is below the tweeter but not at an angle more than 30° below the tweeter, as is outlined in the review.
zxlankyxz posts on July 18, 2020 22:57
I am really like what I am hearing about these RSLs and they look great. I am leaning toward 3x CG25s for the fronts and I am debating about CG3s or CG5s for the surrounds in a 5.1.4. I will be using the C34Es for the 4 ceiling speakers. I would be using this system for watching movies, gaming and also listening to music. I would imagine that for movies there wouldn't be as big of a difference what I pick for surrounds. I am guessing that there would be a larger difference for music though? It's a decent price jump from the CG3 to the CG5, but I would do it if it's worth the performance jump. Attached is a proposed (this is for a basement that we will be finishing) layout for the area. I would likely have to mount them directly on the wall, about 3 feet above ear level and at 90 degrees to the couch with primary listeners on it. It's a large space that is open on all sides, so my primary concern is making sure that the system will fill out the space and sound as good as possible.

38067
Danzilla31 posts on November 16, 2019 12:24
Pogre, post: 1350342, member: 79914
Oh! In the pic it's hard to see the second port/slot on the black one! I assumed they were different designs, lol.

32289
Those speakers look gorgeous bro I love the look there on sale now too which really makes them a very intriguing option
Pogre posts on November 16, 2019 08:53
shadyJ, post: 1350316, member: 20472
There is only one CG25.
Oh! In the pic it's hard to see the second port/slot on the black one! I assumed they were different designs, lol.

32289
shadyJ posts on November 15, 2019 23:52
Danzilla31, post: 1350321, member: 85700
So how bad was the midbass overhang you noticed obviously it was enough for you to mention it but is it a slight change in presentation tonally or something really big enough to notice?
I wouldn't call it overhang. It just has a elevated mid-bass response. I think its noticeable if you are listening to tracks you are very familiar with, but you might not know its there if you aren't familiar with the content. Audible, yes, if you are listening for it, but not intrusive or bothersome. Like I said in the review, I think the speakers sound fine, and I don't think its worth even running room correction programs like Audyssey to finesse the response.
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