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Revel C763L In-ceiling Speaker Review

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amirm

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This is a review, listening tests and detailed measurements of the Revel C763L "LCR" in-ceiling speaker. It is on kind loan from a member and costs US $825.
C763L In-Ceiling LCR Speaker Review.jpg

You see it mounted in the baffle I had to make to measure it. It is an unusual design with that rectangular woofer, dual midrange and tweeter. The latter cluster is pointed "up" in my vertical configuration for testing. In a typical LCR application you would mount them in the ceiling above your flat panel with the angle pointing out to the listening position. While many in-wall speakers are open in the back, the C763L is not:
C763L In-Ceiling LCR Speaker Back Panel Review.jpg


C763L In-Ceiling LCR Speaker back side view Review.jpg


This makes the speaker response much more predictable in low frequencies. But the very small enclosure highly limits the air space in there and hence, low frequency response. As you see in the measurements in the next section, a high-pass filter is built-in, mandating a sub-woofer for full range response.

Measuring these ceiling speakers with angled drivers has proven very challenging. None of our research data applies to them due to the way they are mounted and angled. Still, we can get some useful information out of them so let's get into that.

Note: our company, Madrona Digital, is a dealer for Revel speakers. So feel free to read any level of bias in subjective comments from me.

Revel C763L Measurements

As noted, the C763L was mounted to a baffle (about 4X its size) and special mode in Klippel NFS is used to not only generate anechoic response, but also ignore any back radiation or diffraction from the edges of the baffle ("2 pi measurements"). Due to restriction in how this mode works, the default response is always on an axis that is 90 degrees to the baffle. Think of a line coming out the center of the speaker and going out. In the way it would get used in a ceiling, this is the response you would get if you stood right under it. Here is our "spin" frequency response measurement then:
C763L In-Ceiling LCR Speaker Frequency Response Measurement.png


We see the effect of high-pass filter in low frequency. Then see a more or less flat response until we get to 700 Hz where we start to see a shelf and then a sharp trough. Response then picks back up and is more or less flat again. Company publishes its own spin which roughly matches what I measured:
C763L In-Ceiling LCR Speaker Harman Measurement.png


The trough is less sharp which I think is due to lower resolution measurements from them.

When I reviewed the JBL SCL-5 speaker, designer cried foul that the on-axis response was not useful and suggested showing the 30 degree angle as the "on-axis" and a few above and below to indicate "listening window." Here is that attempt using my measurements:
C763L In-Ceiling LCR Speaker Vertical listening window Frequency Response Measurement.png


I have highlighted the 30 degrees with bold black line. It does indeed reduce the impact of the null between 2 and 3 kHz. But then shows some comb filtering (?) in higher frequencies. And naturally increased energy in high frequencies since we are more aligned with the axis of the tweeter. If you are interested in other angles, here is the full set of them:
C763L In-Ceiling LCR Speaker Vertical full Frequency Response Measurement.png


Negative angles, i.e. going the opposite of the angle of the midrange/tweeter baffle really screws up the response so don't go there.

The use of dual mid-ranges, horizontally placed means that we now get response changes as we go left and right:
C763L In-Ceiling LCR Speaker Horizontal Frequency Response Measurement.png


This would make equalization for multiple seats more difficult.

I am not going to show the early window and predicted in-room response since they don't apply to ceiling mounted speakers, much less one with angled drivers like this. Instead, I optimized the directivity responses more:
C763L In-Ceiling LCR Speaker Horizontal Beamwidth Measurement.png


Good suggestion was made to NOT normalize the directivity plots for this use in the JBL thread so I followed that with some more fine tuning:
C763L In-Ceiling LCR Speaker Vertical Directivity Measurement.png


We now clearly see the desired response in the 20 to 60 degree range which avoids that yellow streak.

Same optimization shows the narrow angle of usage in the other axis:

C763L In-Ceiling LCR Speaker Horizontal Directivity Measurement.png


Translating, if mounted in ceiling, the useful dispersion is 20 degrees to the left and right of the speaker. Sit farther back if you want to optimize how wide of a region this covers.

I could not make near-field measurements because the drivers are so close to each other. But did test for distortion:
C763L In-Ceiling LCR Speaker THD Distortion Measurement.png


I expected the small woofer to blow its brains out but the high pass filter and good engineering saved it from that. The response at 86 dBSPL is excellent. At 96 dBSPL, all the drivers are somewhat unhappy but better than one would expect from such a compact speaker.
C763L In-Ceiling LCR Speaker Relative THD Distortion Measurement.png


Impedance graph shows the high pass filter in the way that line shoots up to infinity as frequencies get down to 0 Hz:
C763L In-Ceiling LCR Speaker Impedance and Phase Measurement.png


Minimum impedance is 4.1 which is typical of speakers these days.

Here is the waterfall display:
C763L In-Ceiling LCR Speaker CSD Waterfall Measurement.png


And step response:

C763L In-Ceiling LCR Speaker Step Response Measurement.png


Revel C763L Listening Tests
Since these speakers have a back box, I decided to clamp the baffle to my speaker stand take a listen. The tweeters were now pointing up toward my head so I could only listen at about 4 to 5 feet or so. I played my reference female clips and when listening at the angle of the tweeters, the sound was surprisingly clean and good. Switching to anything with bass quickly showed the fact there there is little of it there. I then tested the listening angle by gradually going down until I got to the 0 degree and even lower. Boy, the sound becomes horrible if you go below 0 degrees. Even at 0 it was not that usable. Fortunately if you go up 20 or so degrees, you hear a large transformation. So you do want to ignore the on-axis response as shown in the spinorama. And avoid using the same if you plan to use these as Atmos ceiling speakers.

Conclusions
The C763L came out back in 2012 to help the custom install industry with a good solution for ceiling mounted home theater applications. It is a universal rule that in most living room applications, decision is made to only mount speakers on the ceiling. TV is usually (unfortunately) mounted above a fireplace and such, which eliminates the option of in-wall speakers. The C763Ls attempt to solve that impossible problem with angled drivers. A cluster of drivers in that small enclosure though creates major, major challenges as we see in the measurements. Subjectively I thought they sounded good on the design axis but of course no match for any standard speaker.

Many are thinking about using these speakers for Atmos height speakers. I don't see them being optimal in this configuration given the narrow usable angle. I hope to review more in-ceiling speakers to see if we can find the ideal ones for this use.

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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/
 

sweetchaos

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Thanks for the review.

I’m really want to see someone send in Kef’s Meta in-wall/in-ceiling architectural speaker.

Ci250RRM-THX​

 

martijn86

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TV is usually (unfortunately) mounted above a fireplace

We don't all live in Nort America. It certainly makes me uncomfortable when I see a US home renovation TV-Show and they finish a beautiful interior with a 65" TV hanging slightly below the ceiling.
 

AndreaT

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The Art and Science of ceiling speakers seems to have miles and miles to go before achieving good results. It is probably bad to have speech frequencies so much in a valley of the speaker’s frequency response. How does the spoken word sound like? Are the words intelligible and are the actors’ voices reproduced with the personal signature of each?

Thank you for a great review, Amir. Not a great speaker to solve the problem of ceiling mounted sound systems.
 

PeteL

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I concur. My home from a decade ago:

View attachment 264726

Super uncomfortable viewing angle (size reference 55” OLED).

Ouch, that's pushing it to a point where even someone who couldn't care less about audio can tell you that your backwall is quite "reflective".
On another note, I tend to forget about fireplace considerations. My city has banned wood burning for almost a decade. Is it still something common in the rest of the world?
 

tktran303

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It doesn’t use wood. It used natural gas and fake embers. It’s all ornamental, like that
fireplace step, made of marble, and timber parquetry flooring, style before substance. Like the TV with “twoofers” firing backwards into the brickwork. Even the TV is mounted with a single puck-like device ala “picture frame”

The only good thing about that house was I moved out of it.
 
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Ajax

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Ouch, that's pushing it to a point where even someone who couldn't care less about audio can tell you that your backwall is quite "reflective".
On another note, I tend to forget about fireplace considerations. My city has banned wood burning for almost a decade. Is it still something common in the rest of the world?
Where's your city?
 

Cars-N-Cans

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Thanks for the review.

I’m really want to see someone send in Kef’s Meta in-wall/in-ceiling architectural speaker.

Ci250RRM-THX​

Genelec is releasing new in-ceiling and pendant speakers as well.


It would be very interesting indeed to see how these all measure given how good KEF and Genelec speakers are in general.
 
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Ellebob

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The problem with speakers like the Genelec and the Kef is they will probably measure well on and off axis but if used as an LCR or Atmos at 45 degrees they still will not be great. A good off axis response still rolls off and at 45 degree is probably 5db down from 1khz higher. Definitely audible and that's a good speaker. Angled speakers should be a good solution but they need to angle at least 30 degrees with probably 45 degrees or more especially if used as an LCR. The ones that only angle 15 degrees or have a pivoting tweeter are pretty much useless for these applications. A number of companies make angled in ceiling speakers, Triad, Paradigm, Golden Ear, Def Tech, even monoprice. This design is a little more unusual with a woofer that is not aimed but in theory should be more omnidirectional at lower frequencies. As Amir noted at 0 degrees these things stink but they shouldn't be used at zero degrees and probably more in the 30-60 degree range. Probbly helps if the room is carpeted as well.

In general, I m not a fan of in ceiling LCR systems but I did live with one for several years and it was quite enjoyable. It was in a room where the screen came down in front of a fireplace and the projector was mounted in a soffit on the other side of the room. The whole system was in ceiling, including the subs. It sounded good and I enjoyed watching that system. Was it the best system I ever heard? definitely not! But, it wasn't crap either. It was perfect for that room to keep a good aesthetic. At my work I run into Kef quite a bit and the company I work for also carries Kef and Genelec. I have seen a number of installations where they are used as Atmos and frankly it is not good if put 45 degrees out. They need to be closer like 30 degrees or less. The systems I have heard with angled ceiling speakers definitely have a much better Atmos presentation, and it just makes sense. Acoustics 101 is speakers should aim towards the listeners.

Dolby's own demo rooms which has speakers mounted on the ceiling have them angled towards the listeners. So a good angled in ceiling solution is needed for Atmos as many home owners aren't willing to mount speakers on their ceiling. Much of the present company excluded:) Hopefully, more companies will come out with good sounding angled speakers. I don't know how easy or hard it would be to have some type of mounting so the Klippel can easily measure these speakers at their intended angle. That way it would be easier to get a better idea of their performance.
 
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Ouch, that's pushing it to a point where even someone who couldn't care less about audio can tell you that your backwall is quite "reflective".
On another note, I tend to forget about fireplace considerations. My city has banned wood burning for almost a decade. Is it still something common in the rest of the world?
For some of us. I run my fireplace during winter months when it's cold enough for it.
 

EJ3

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On another note, I tend to forget about fireplace considerations. My city has banned wood burning for almost a decade. Is it still something common in the rest of the world?
I have never heard of burning (indoors or out) being banned anywhere near here. Except out on the beaches, where the marshes could catch fire & burn up the multi-million $ homes & kill people. We do have very dry times when outdoor burning is highly regulated or banned.
Many of us set our lawns on fire annually to do a controlled burn off of the underbrush and heat the weed seeds up so that they don't germinate.
This avoids forest fires from the build up of too much underbrush (think California).
This also avoids putting pre-emergent weed killer (anti-fertilizer?) down, which can run off into the ground water, getting into our underground aquifers [some of the city's city water comes from there), getting into our salt water creeks & the fish, crabs, shrimp, oysters, etc that we eat, and getting into our fresh water river (the city's dominant water supply) which we drink.
The pre-emergent would also get into our fresh water rivers and their fish, and wildlife: deer (venison), feral pig, alligators, racoon, possums, squirrels, etc, that we also eat.
It looks to me like the choices are: have major forest fires (usually caused by lightning strikes and having lots of underbrush to burn) that take out whole communities, destroy people, wildlife, their habitats and poison the ground, also destroying wildlife, people and their habitats.
Or having controlled burns.
Alternatively, I guess, one could live in a big city, something I have wasted a few years doing several times in my life and have no intention of ever doing again.
 
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EJ3

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All these ceiling speaker tests just convince me to go with Plan A for my new listening room/HT build. Plan A being small good measuring high-output low compression bookshelf speakers on angled VESA mounts (eg Arendal 1961 bookshelf speaker).
I have a friend that has all of his 5.1 speakers (except the sub) mounted on locations of the ceiling that he sussed out when building the house many years ago.
They work very well.
They are on some kind of adjustable gimble mount.
The speakers are of the Mirage brand but I do not know what model # they are.
If the ones you are setting up for ATMOS work as well as his do for his setup, you'll be happy.
 
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