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Revel Concerta2 C25 Review (Center Speaker)

Rate this speaker:

  • 1. Poor (headless panther)

    Votes: 18 10.1%
  • 2. Not terrible (postman panther)

    Votes: 51 28.7%
  • 3. Fine (happy panther)

    Votes: 89 50.0%
  • 4. Great (golfing panther)

    Votes: 20 11.2%

  • Total voters
    178

amirm

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This is a review and detailed measurements of the Revel C25 center home theater speaker. It is on kind loan from a member and costs US $825.
Revel Concerta2 C25 Review Center Home Theater Speaker.jpg


The C25 is gorgeously finished and cabinet feels very solid. There are a set of four screws on the bottom that you can use with a mounting system to hang the speaker if desired.

Back panel shows lack of port which is typical of center speakers:
Revel Concerta2 C25 Review Back Panel Center Home Theater Speaker.jpg


You can see the nice gloss finish of the speaker.

NOTE: our company Madrona Digital is a dealer for Harman products (although we don't do any retail business). As such, you can feel free to read any level of bias in my subjective remarks.

Measurements that you are about to see were performed using the Klippel Near-field Scanner (NFS). This is a robotic measurement system that analyzes the speaker all around and is able (using advanced mathematics and dual scan) to subtract room reflections (so where I measure it doesn't matter). It also measures the speaker at close distance ("near-field") which sharply reduces the impact of room noise. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber. In a nutshell, the measurements show the actual sound coming out of the speaker independent of the room.

Measurements are compliant with latest speaker research into what can predict the speaker preference and is standardized in CEA/CTA-2034 ANSI specifications. Likewise listening tests are performed per research that shows mono listening is much more revealing of differences between speakers than stereo or multichannel.

Reference axis was the center of the tweeter (aligned by eye). The grill was not used although it is a very transparent one so it should not impact the sound much. Measurement room was at 10 degrees C which may lower bass output a bit. Accuracy is better than 1% for most of the audio spectrum degrading to 2% above 4 kHz.

Revel Concerta2 C25 Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker is and how it can be used in a room. This so called spinorama shows us just about everything we need to know about the speaker with respect to tonality and some flaws:

Revel Concerta2 C25 Measurement Frequency Response Center Home Theater Speaker.png


I was very impressed with the frequency response of the C25. Other than a gentle rise in mid region, it is almost flat on axis with excellent directivity. Many Revel speakers have low sensitivity but not the C25. It is better than 90 dB! Lack of port means the classic drop off in bass response which starts at 200 Hz.

You can see the nice early window directivity when we look at the most important reflections in a room:

Revel Concerta2 C25 Measurement Early Window Frequency Response Center Home Theater Speaker.png


Putting both graphs together we get our in-room predicted in-room frequency response which predictably is excellent:

Revel Concerta2 C25 Measurement Predicted in-room Frequency Response Center Home Theater Speaker.png


Story is not perfect though. We know this type of 2-way design causes cancellation and narrowing of the response in the woofer region and that is what C25 does:

Revel Concerta2 C25 Measurement Horizontal Beamwidth Center Home Theater Speaker.png


Revel Concerta2 C25 Measurement Horizontal directivity Center Home Theater Speaker.png


You need to sit quite far from the speaker to have decent coverage for seating. I will report on this in my listening section.

Quite the opposite is the case in vertical dimension providing near perfection:
Revel Concerta2 C25 Measurement Vertical directivity Center Home Theater Speaker.png


Another impressive area of performance is incredibly low distortion especially given the small drivers here:

Revel Concerta2 C25 Measurement THD Distortion Response Center Home Theater Speaker.png


Revel Concerta2 C25 Measurement Distortion Response Center Home Theater Speaker.png


Narrow spikes in these graphs indicate resonances by the way which we can confirm in the impedance and phase graph:

Revel Concerta2 C25 Measurement Impedance and phase Response Center Home Theater Speaker.png

And also visible in CSD/waterfall display:

Revel Concerta2 C25 Measurement CSD Waterfall Response Center Home Theater Speaker.png


Finally, for those looking for more timing measurements, impulse and step responses:

Impulse response h(t).png


Step Response.png


Revel C25 Listening Tests and Equalization
The first impression was delightful mid and high frequencies but lack of bass. First correction I applied was for the slight rise in on-axis response between 1 and 2 kHz:

Revel Concerta2 C25 Equalization EQ Center Home Theater Speaker.png


That still did not create an enjoyable experience. Problem was that there was enough bass there to think that there was not enough of it! In other words, if the speaker didn't play any bass you could just dismiss that aspect. Here, the bass response is quite anemic, constantly reminding you that there is not enough of it. Given the exceptionally low distortion I took a shot at boosting the upper bass frequencies with Band 1 filter and I was shocked what a great improvement it provided. Speaker tonality became much warmer and now there was good bit of tactile bass with no audible sign of distortion!

I tested for horizontal coverage and answer there is not good. I could only move half a seat before tonality changed. So if you are going to cover even a medium seating area, the response would not be optimal.

I then turn the speaker 90 degrees. The sides are flat and wide so speaker was quite stable this way. What I heard was mesmerizingly good! Spatial projection (halo around the speaker) enlarged and I was listening to truly high fidelity sounding speaker.

Conclusions
This little speaker (less than 24 inches wide), is superbly designed in many areas but can't escape the physics of dual woofers causing narrowing of the response in horizontal axis. As such, it is not a great choice for a center speaker if you want coverage for more than one seat. Use it for one seat and/or rotate it vertically and you have a compact yet fantastic speaker with just two EQ filters. I am still smiling about how good the sound was in this usage. Part of the credit goes to dual woofers providing exceedingly low distortion, enabling you to play quite loud with no sign of strain or distortion.

Without EQ and for center usage, I can't recommend the Revel C25. With EQ and narrow seating are horizontally or vertically otherwise, it is a superb sounding speaker despite its tiny size and gets my limited recommendation that way.

P.S. One note on the price. From what I have seen in the last couple of years, Revel dealers significantly discount speakers so don't go by the list price I showed in the first part of the review.

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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

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respice finem

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Fine IMHO, esp. the low distortion.
If you don't "abuse" it with much bass, which is easy to avoid via AVR, maybe even "golfing panther area".
 
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Ouwebok

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Best centerspeaker design may be coaxial.. surround systems send all sub-100Hz to the sub/main speakers so closed center designs make sense to me. It is very interesting to see that Amir adds the ‘WA-TuneTot’ pseudo-bass bump at 115 Hz and it adds to the perceived quality of sound.
 

Nwickliff

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Best centerspeaker design may be coaxial.. surround systems send all sub-100Hz to the sub/main speakers so closed center designs make sense to me. It is very interesting to see that Amir adds the ‘WA-TuneTot’ pseudo-bass bump at 115 Hz and it adds to the perceived quality of sound.
Using Kef q100 as my center on its side currently with the port stuffed.
 

DSJR

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Bearing in mind the cabinet or close to wall location of centre speakers like this, plus the need primarily for dialogue, do you really NEED extra bass extension, messing with the cabinet it'd be on or in and enhanced by a rear wall mounting and the slight upper mid lift will slightly enhance perception of clarity I suspect. This box isn't really designed for free space full range reproduction is it? Mind you, a pair turned 90 degrees in a smallish room and stand or shelf mounted looks to make for a very pleasant stereo setup possibly.
 

Koeitje

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Why don't they make it vented to help the low-end output? Apart from that its excellent, not everybody has the space to put up a big center speaker.

Really like to see how the Kef R2c performs, that seems to be a smarter design but still relatively compact.
 
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Mauro

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Why don't they make it vented to help the low-end output? Apart from that its excellent, not everybody has the space to put up a big center speaker.

Really like to see how the Kef R2c performs, that seems to be a smarter design but still relatively compact.
Erin’s measurements
 

tktran303

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According to Dolby specs, a ‘full range’ speaker should go down to 120hz, whilst THX say 80hz, with everything else sent to the sub.

If you use those standards as being the lower target instead of hoping for 20hz, there’s really not much to complain about at the bottom end.

Hmm. I’m not sure I agree with that interpretation.

The Dolby spec, from my recollection, calls for a dedicated LFE channel. This is brick wall limited for <120Hz.

DTS doesn’t have a discrete LFE channel; and calls for sending frequencies below 80Hz to the subwoofer.

The main screen channels (L, C, R and CL and CR) should be full range. By definition
Frequency Response: 80 Hz to 16 kHz, ±3 dB, with -6dB point is 40Hz
 

erlangreg

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Central speaker needs no bass, so "bass drop off" isn't an issue, I see no point in testing a single unit from 2.1 or 5.1 system and blaming it for low amount of "bass", "lack of port" then playing with EQ to boost low frequencies etc because in "2.1" and "5.1" ".1" means there should be a subwoofer. And you usually don't care about directivity of low frequencies — due to the size of soundwaves you cannot precisely tell where they are coming from.
 

Morpheus

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I don't fully understand the matematics involved ..Can someone explain why with such a narrow horizontal beamwidth between 500 and 2500Hz and an abrupt widening above that, with a vertical that is almost regular and textbook perfect and doesn't compensate ( overdo) that bottleneck area with a widening there, nor there is significant boost of spl in the on axis response, we get such a good spinorama, with almost no anomalies in that critical region?
Is the spinorama an adequate yardstick for special use loudspeakers such as these?
I first thought, wow, they somehow made an incredible low crossover point work with that tweeter/waveguide , maybe sacrified distortion a little distortion ( no, actually one of the lowest I've seen here, great job), when I first saw the spin, but no breakthrough there, the crossover looks to be at the usual region as we infer from the beamwidth trace problems.
Probably a nice choice upright, with two for stereo, but, I am curious you ( Amir) didn't complain, as we know you prefer a robust low end, was the subjective impression not exactly what the measurements show?
On another vein, that peak filter on 115 Hz, that's my subjectivity guilty pleasure ..
I Eq my Senn 800S on the DAC as per measurements but I put the same extra narrow 3db bump there for seasoning, it gives me back the slight lack of impact on bass and drums I experience on them, and a slightly warmer sound without muddying anything.
 
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3125b

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Why do all these manufacturers try to make this design work again and again - it just doesn't.
Why not just use a single coaxial. The center channel doesn't need much bass extension so even a small-ish one would be fine.
For example a KEF LS50 is 20cm wide, so turning that on its side would make it 20cm high, only 2cm higher than this.
 

respice finem

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Why do all these manufacturers try to make this design work again and again - it just doesn't.
Why not just use a single coaxial. The center channel doesn't need much bass extension so even a small-ish one would be fine.
For example a KEF LS50 is 20cm wide, so turning that on its side would make it 20cm high, only 2cm higher than this.
Only my guess - perhaps because not every manufacturer makes coaxial drivers, or these are more expensive to source?
 

3125b

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Granted, KEF has a 30 year head start developing coaxial drivers, but I'm pretty sure Kali Audio, a small manufacturer with something like 20 employees, developed their own rather decent coaxial drivers for their IN-line of studio monitors.
Revel Audio, the luxury brand of mighty Harman International Industries, must be capable of doing that as well.
 

beagleman

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Why do all these manufacturers try to make this design work again and again - it just doesn't.
Why not just use a single coaxial. The center channel doesn't need much bass extension so even a small-ish one would be fine.
For example a KEF LS50 is 20cm wide, so turning that on its side would make it 20cm high, only 2cm higher than this.


The center should be able to operate down to about 80Hz.

I have center speakers that DO this and lower, and they do sound better than the ones that roll off in the mid 100s-200hz

The reason they make this design is, it is a mild trade off, and not all people are bothered by the tonality change due to be somewhat off axis.
This forum puts a lot of focus on this aspect and often will downplay other aspects that are less than stellar.

I think that focus is somewhat just "Baked" into this forum.


Not saying it is not an issue, but in practice it may bother a dozen guys (or more) in here, but doubt many people, even those into audio like most of us, find it be some huge deal breaker, or something that inhibits enjoying a movie.....
 
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tktran303

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The center should be able to operate down to about 80Hz.

I have center speakers that DO this and lower, and they do sound better than the ones that roll off in the mid 100s etc.

The reason they make this design is, it is a mild trade off, and not all people are bothered by the tonality change due to be somewhat off axis.
This forum "Plays up" that aspect.

For what it is worth, I was truly never bothered by this in real life experiences with half a dozen center channels under my belt, UNTIL I started reading about it being such a big "Issue" in the forum.

Not saying it is not an issue, but in practice it may bother a dozen guys in here, but doubt many people, even those into audio like most of us, find it be some huge deal breaker, or something that inhibits enjoying a movie.....

Exactly.

It’s like turning a speaker upside down and point the mic at the woofer as the acoustic reference point. Measures very differently.

But listening on the woofer axis.
It Still sounds like the same speaker !!!

I’d like to see a laptop or TV’s built in speaker up to the Klippel, and see how it measures. Junky Funky, I bet.

But plenty (most) people can still enjoy music from their laptop or TV…
 
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