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Revel Concerta2 C25 Review (Center Speaker)

Rate this speaker:

  • 1. Poor (headless panther)

    Votes: 19 10.5%
  • 2. Not terrible (postman panther)

    Votes: 52 28.7%
  • 3. Fine (happy panther)

    Votes: 90 49.7%
  • 4. Great (golfing panther)

    Votes: 20 11.0%

  • Total voters
    181

beagleman

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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.
I do not think all audio manufacturers feel that a coaxial design has enough positives to outweigh the negatives.

It is not an instant cure to everything to simply coaxially mount a tweeter into a mid-woofer. There are many issues.

You know how they say "If it was that easy, everyone would do it"?....
 

carlob

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You are not going to use a center channel without a subwoofer or at least full range fronts, don't you?

In a multichannel setup you'll likely be crossing it over in the 80Hz-120Hz range
 
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abdo123

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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!

Low frequency extension is by far the most important factor for speaker preference, this is why the C10 recommendation shocked me so much (which rolled off at 400Hz).
 

AndreaT

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After experimenting 10 or so years ago with one center channel from ProAc and one from Paradigm, the two speakers are now lying in the corner of one of my rooms, hopefully acting as passive resonators and diffusers...A well oriented 2.1 system is all I need to enjoy watching movies, because the center channel IMO adds way more problems than it solves. The only limitation is from those sources that do not offer a 2.1 sound options, only a 5.1, just a few among the movies I choose to watch. The stereo sound experience can be created pretty well with a R and L source: when the mastering is well done and the speakers are well positioned I get (or I believe I do) what I wish for. RIP center channel.
 

Dj7675

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Low frequency extension is by far the most important factor for speaker preference, this is why the C10 recommendation shocked me so much (which rolled off at 400Hz).
While the anechoic measurements of the C10 do in fact show that, that is not what the in room installed measurements would be. Revel spec is -3dB at 110hz which I have shown it does in fact hit when installed.
Similarly, I would expect a large portion of center channels to be installed very near walls and would expect a significant bass boost as a result. For example I have a Revel C208 installed under my screen flush against the wall and as a result of the shallower roll off of the sealed design and against a wall, it starts to roll off around 40hz even though the anechoic measurements show more like 80hz.
Not saying that lower extension isn’t better, because I think it is, but when installed they often have much better extension than the measurements show.
 

abdo123

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While the anechoic measurements of the C10 do in fact show that, that is not what the in room installed measurements would be. Revel spec is -3dB at 110hz which I have shown it does in fact hit when installed.
Can you share the measurements?
 

beagleman

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After experimenting 10 or so years ago with one center channel from ProAc and one from Paradigm, the two speakers are now lying in the corner of one of my rooms, hopefully acting as passive resonators and diffusers...A well oriented 2.1 system is all I need to enjoy watching movies, because the center channel IMO adds way more problems than it solves. The only limitation is from those sources that do not offer a 2.1 sound options, only a 5.1, just a few among the movies I choose to watch. The stereo sound experience can be created pretty well with a R and L source: when the mastering is well done and the speakers are well positioned I get (or I believe I do) what I wish for. RIP center channel.

Yikes, me thinks you simply do not like the home theatre experience.

Unless ONLY YOU sit dead center and watch movies, a Center speaker is EXTREMELY important for the overall experience.
You are basically just watching stereo TV, not surround sound with a 2.1 mix.
 

Dj7675

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Can you share the measurements?
Sure, here is the measurement of the C10 taken at the installed location (9 point Dirac averaged measurement). Boundary has a huge impact when installed on wall in the case of the C10. If near a wall it would have a similar affect depending on how close to the wall.

B703B025-9B92-4F18-9326-EE56688D6C90.png
 

beagleman

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You are not going to use a center channel without a subwoofer or at least full range fronts, don't you?

In a multichannel setup you'll likely be crossing it over in the 80Hz-120Hz range


I hate to say this, but many of the smaller centers roll off way too much, to make it EASY to integrate to a sub, without being able to locate voices.

A center such as this one, would be closer to 150-160 hz to cross ideally.

The issue encountered, by running the sub too high, is usually a boomy male vocal, or a mid bass dip if trying to cross it too low.
 

beagleman

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While the anechoic measurements of the C10 do in fact show that, that is not what the in room installed measurements would be. Revel spec is -3dB at 110hz which I have shown it does in fact hit when installed.
Similarly, I would expect a large portion of center channels to be installed very near walls and would expect a significant bass boost as a result. For example I have a Revel C208 installed under my screen flush against the wall and as a result of the shallower roll off of the sealed design and against a wall, it starts to roll off around 40hz even though the anechoic measurements show more like 80hz.
Not saying that lower extension isn’t better, because I think it is, but when installed they often have much better extension than the measurements show.
But when putting a center against a wall or on wall, you are effectively boosting the 125-250 Hz region by about 10 db.

That creates a very boomy sounding bass. Far better to find a center that is flat TO 80 hz or so, rather than rely on booming bass from being close to a wall or on wall.
 

restorer-john

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@amirm the impulse response appears to be unfortunately yet another Klippel disaster.

We have a bunch of pre-impulse ringing and a bunch of post impulse ringing which clouds the actual response. How is the plot remotely useful? What is real and what isn't? Please explain.

We know everything before the actual impulse doesn't exist acoustically, so what use is the SinC interpolation of what comes afterwards?

1640960788931.png
 

abdo123

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Sure, here is the measurement of the C10 taken at the installed location (9 point Dirac averaged measurement). Boundary has a huge impact when installed on wall in the case of the C10. If near a wall it would have a similar affect depending on how close to the wall.

View attachment 175766
Thank you for sharing, I found best results by crossing speakers at their -3 dB (anechoic) points. Your subwoofer's output also look incredibly lower in amplitude (anechoicly) than the speakers, you might be seriously over driving the C10 this way.
 

Dj7675

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I hate to say this, but many of the smaller centers roll off way too much, to make it EASY to integrate to a sub, without being able to locate voices.

A center such as this one, would be closer to 150-160 hz to cross ideally.

The issue encountered, by running the sub too high, is usually a boomy male vocal, or a mid bass dip if trying to cross it too low.
Revel specs show -3dB at 80hz/-6dB at 68hz. These specs obviously are not anechoic, so much be the typical installed spec which would be near a wall in most installs. Should be able to do 80hz-100hz just fine I would expect. I would agree that male vocals that creep into subs can be an annoying issue though!
 

Mosquito

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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.
View attachment 175707

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:
View attachment 175708

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:

View attachment 175709

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:

View attachment 175710

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

View attachment 175711

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:

View attachment 175712

View attachment 175713

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:
View attachment 175714

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

View attachment 175715

View attachment 175716

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

View attachment 175717
And also visible in CSD/waterfall display:

View attachment 175718

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

View attachment 175719

View attachment 175720

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:

View attachment 175721

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 a person with zero interest in HT I'm thinking that two of these, with a sub, can make a superb stereo setup for a fraction the cost of a true Revel full ranges.
 

carlob

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I hate to say this, but many of the smaller centers roll off way too much, to make it EASY to integrate to a sub, without being able to locate voices.

A center such as this one, would be closer to 150-160 hz to cross ideally.

The issue encountered, by running the sub too high, is usually a boomy male vocal, or a mid bass dip if trying to cross it too low.

You need to measure it in your room and with the other 4.1 speakers before making crossover decisions. In any case seems to me that bass response extension is not that important for a center. In addition this C25 is probably tuned to go with the Revel Concerta2 speaker series.
 

Dj7675

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But when putting a center against a wall or on wall, you are effectively boosting the 125-250 Hz region by about 10 db.

That creates a very boomy sounding bass. Far better to find a center that is flat TO 80 hz or so, rather than rely on booming bass from being close to a wall or on wall.
EQ (Dirac/Audyssey) cuts that excess energy, so that isn’t an issue. The point is there isn’t a hole under 400hz. There is plenty of energy there and can be reduced to the proper levels with EQ.
 

Dj7675

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Thank you for sharing, I found best results by crossing speakers at their -3 dB (anechoic) points. Your subwoofer's output also look incredibly lower in amplitude (anechoicly) than the speakers, you might be seriously over driving the C10 this way.
Not the case.. even with a room curve with HARMAN type of boost, EQ is providing cuts. There is a room null in there but I have DLBC that actually fixes that quite nicely providing smooth response with a 5.5dB boost at 20hz with the boost starting around 150hz.
 

abdo123

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Not the case.. even with a room curve with HARMAN type of boost, EQ is providing cuts. There is a room null in there but I have DLBC that actually fixes that quite nicely providing smooth response with a 5.5dB boost at 20hz with the boost starting around 150hz.
Sorry i'm not buying it :)

In my room this:

kh750_kh80_freq_resp_510.gif


Becomes this (my subwoofer is flat to 50Hz anechoically):

1640962296176.png
 

Dj7675

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But when putting a center against a wall or on wall, you are effectively boosting the 125-250 Hz region by about 10 db.

That creates a very boomy sounding bass. Far better to find a center that is flat TO 80 hz or so, rather than rely on booming bass from being close to a wall or on wall.
It will boost more than just that region. Here is a simulation from JBL comparing on wall and anechoic response of a JBL control 25AV. This is a small ported speaker, so the sealed nature of the C25 will actually respond with better on wall extension and has 2 woofers which should provide more clean output.
670B3E66-7786-42CA-BABF-CABF69A33E5D.jpeg
 

Dj7675

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And here is the difference of a larger speaker anechoic vs on wall install of a JBL control 29av.. and again this is a ported speaker with a sharper roll off than a sealed design. I guess my point is that installed location can make a big difference and one shouldn’t automatically assume the worst case anechoic response will be what you get when installed in room.

29CBD30B-3D9B-4AA9-8D24-B9709B2DB871.jpeg
 
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