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Elac Reference UCR52 Review (Center Speaker)

hmt

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R3 would work well on its side, or vertically. Any good coax design would work fine on its side.



The only coaxes besides KEF that I have seen passable performance from are the relatively small bandwidth models in Kali and Genelec monitors.

Actually it looks like that the R3 on its side still performs better than the R2c. :D
 

Robbo99999

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I'm sure there's better options out there, nice investigation and tying down of the cabinet resonance @amirm , I enjoyed that part.
 

pseudoid

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The only good way to get rid of a cabinet resonance is to replace the cabinet. I've had to replace some in warranty. ...
ELAC Reference UCR52 webpage does not provide specifics about the construction or the internal bracing of this speaker cabinetry.
However, the following 2 specs almost make it sound like, at least, someone invested forethought at the initial stages of the design.
Cabinet: CARB2 Rated MDF
Net Weight: 29.04 lbs
I haven't a cloo what a "CARB2 MDF" is but at 29 pounds; one could only hope that the MDF is at least half an inch in thickness!
 

restorer-john

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Main point is since he left KEF we've seen evidence that Andrew Jones knows how to design coax speakers...

It's not like he invented coaxial speakers. Plenty of manufacturers were doing coaxials before he was born.

And, think of the entire 1980s and 90s where coaxial driver car audio was huge.
 

Music1969

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It's not like he invented coaxial speakers. Plenty of manufacturers were doing coaxials before he was born.

And, think of the entire 1980s and 90s where coaxial driver car audio was huge.

Yes I'm arguing the other side, ie it's not like he doesn't know how to do coaxial speakers.

Context is important. My original reply was to the comment "not surprising others have a way to go."

As I already wrote, we've seen AJ can competently design coax speakers.

The problem is performance inconsistencies (unless deliberate)
 
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Alice of Old Vincennes

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Expense is an issue not just in terms of material but also complexity of construction. Thick mdf is harder to cut and assemble. Damping materials and Bracing also adds complexity.

Any box will have resonances at some frequency. And they are not always so easy to dampen.
Have you ever worked with 3/4 vs 1 inch? Price difference is negligible compared to cost of rest of components. Cutting one inch mdf with decent table or miter saw is easy.
 

Ata

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Actuall I wonder if one could just use an R3 as a center and call it a day.

Of course you can, it is just that with Q150 you will get 80-90% of the result at 20-25% of the cost. This is theoretical, though, as we have not had Q150 measured here, only assuming it is roughly comparable to Q350.
 

anphex

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@amirm, what is your opinion on using MTM D'appolito speakers as vertical stereo speakers? I would be also very curious about seing how the same center speaker behaves in vertical orientation.

Secondly I'd love to see a kind of hard off axis (horizontal)measurement for 15°, 30°, 45° and 60° degree for simulating people not sitting in the sweet spot. Horizontally placed MTM d'appolito all have unavoidable horizontal effacements don't they? I'd love to see how the perform in that category.
 
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pseudoid

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Surely you don't mean to imply that Amir is surly. ;)
Surely, you can call @amirm anything you want (IMHO: even surly or Shirley) but I am not sure if he can handle being called late to the dinner table.
[no disrespect to any Shirleys, even if they are a surly bunch!]
 

stevenswall

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Revel ceiling speakers sure look coaxial to me.

Andrew Jones prefers the term Dual Concentric... The offset coaxials Revel makes don't have the advantages of a KEF/Genelec/Elac coaxial.

Not sure what the best way is to refer to things, but Coaxial seems to be the most common, though maybe coincident concentric drivers would be more accurate, albeit a mouthful.
 

Alice of Old Vincennes

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Andrew Jones prefers the term Dual Concentric... The offset coaxials Revel makes don't have the advantages of a KEF/Genelec/Elac coaxial.

Not sure what the best way is to refer to things, but Coaxial seems to be the most common, though maybe coincident concentric drivers would be more accurate, albeit a mouthful.
I guess dual concentric don`t have coaxial issues?
 

stevenswall

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I guess dual concentric don`t have coaxial issues?

Depends on what you mean. Any kind of speaker can have issues due to cost or engineering time constraints. There is nothing inherently flawed with dual concentric/coaxial drivers, though there may be inherent issues with offset coaxial drivers, I'm not sure.
 

kencreten

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This is a review and detailed measurements of the Elac Unifi Reference UCR52 center home theater speaker. It was kindly purchased new by a member and drop shipped to me. The UCR52 costs US $700.

The UCR52 enclosure is nice looking but I don't the wisdom of having highly reflective, chrome polished rings around a speaker in a theater application:

View attachment 158028

Even during music listening I found the reflective edges eye catching in the wrong way. There is a magnetic grill so you can hide them.

This is a three-way speaker with dual woofer and a mid-range+tweeter coaxial/coincidental driver. 3-way is my preference for center speaker to avoid directivity dips with so called MTM 2-way speakers.

Back panel sports very nice looking and feeling binding posts:

View attachment 158029

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. Using computational acoustics, far-field response is computed and that is what I present. Both of these factors enable testing in ordinary rooms yet results that can be more accurate than an anechoic chamber.

I performed over 1000 measurement which resulted in error rate of about 1%.

Reference axis is approximately the center of the tweeter. Grill was not used.

Unifi Reference UCR52 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 158031

Wow, I must say, I did not remotely expect to see such a rough frequency response. It has both macro and micro level variations all over the place. Near-field measurements of each sound radiating elements explains some of this:

View attachment 158033

Notice the very uneven response of the coaxial driver. We also have a port/cabinet resonance around 1 kHz. Let me jump ahead and show you distortion response:

View attachment 158034

View attachment 158035

When I was measuring the speaker I distinctly heard a sharp sound coming part way through the sweep. Note that I wear strong hearing protection so normally don't hear problems with speakers unless they are very severe. And this was. I got close to the speaker and put my hand on the cabinet. Right when I heard the output of norm, higher pitch sound, I would also feel the cabinet resonating. This occurred with the 96 dBSPL sweep. So I looked and saw that large peak between 500 Hz and 1 kHz. So I created a sweep that only excited that range of frequencies and I could hear the tone again.

Last time I reported a resonance like this it too was an a Elac speaker, the Unifi 2.0. There was a lot of doubt then as to whether this was really there so I decided to make a recording of the sweep. I used my phone to see if it can capture it and it did. See the sample zip file. Here is the amplitude evenelop:

View attachment 158036

You can clearly see the amplification of the tone before the sweep ends. If you play the audio file in an audio workstation software, you can easily hear the zing at the end in sync with that peak.

I tested this at 86 dBSPL and it was harder to hear it there.

Anyway, back to our measurements, here is our early window reflections:


View attachment 158037

Response is thankfully smoothed out due to a number of reflections being summed but we still have a shelving of upper bass and midrange. This results in the same issue in predicted in-room frequency response:

View attachment 158039

Horizontal beamwidth is pretty uneven but fairly wide in mid-frequencies:

View attachment 158040

Same is seen in the colored contoured version:

View attachment 158041

There are sharp edges around the metal the surrounds the coaxial driver. So I wonder it is causing some diffractions here that we see at the edge of our envelop.

Strangely vertical directivity looks better even though it audibly is not as significant:

View attachment 158042

I guess it doesn't have two woofers flanking it like the horizontal plane does.

The three snapshots I take land in the sweet spot of the speaker so show good response:

View attachment 158043

Impedance dips to 5 ohm so make sure you have a decent amplifier to drive this speaker:

View attachment 158044

Note that our resonance shows up clearly here as well in both phase and amplitude response.

Elac Uni-fi Reference UCR52 Listening Tests and EQ
Having seen the measurements in advance, I expected poor sound but did not get it. What was there was quite pleasant with very good dynamic ability. Wondering if I had lost all ability to subjectively assess speakers, I went ahead and put in a couple of filters to deal with that step up response between 200 and 1000 Hz:

View attachment 158045

At first, the difference was subtle but then I listened for 15 minutes and then turned off the EQ. Wow, so much muddier and a bit tubbier without EQ. Vocals came forward now which is what you want in a center speaker.

Conclusions
I know the word "reference" has been bastardized in audio to almost mean nothing but still, I expected more, far more from Elac and Andrew Jones. What were they thinking? How could they produce such a technically flawed speaker? When I can hear a resonance with hearing protection in a simple log sweep, surely they could too. Do they only play at low and modest levels and don't hear such things? If so, what is up with the uneven frequency response? Is this all tuned by ear? Why is it so uneven anyway? Was this pushed out the door before being finished? Lot of questions.

Thankfully or not, in a battle of subjectivity vs objectivity, with a bit of EQ it performs a lot better than it should. Dual woofers give it high SPL playback ability which is an effective way to get on my good side. :) This is super important in home theater applications were the center speaker carries most of the burden as it has to show all that is seen on screen.

On the resonance, I could not get a clear case of it showing up. Either I was not playing loud enough or that the tone was getting added to other parts of the music and it was not as obvious as it was in Uni-fi 2.0.

Anyway, I think technically the ELAC Uni-fi Reference UCR52 is a failure and I can't recommend it. Subjectively, with some EQ it can be made to sound good. You get to decide which side of me you want to believe. :)

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