Elac BS U5 Slim 3-way Coaxial Speaker Review

[981CS]

Curious as well! The PIR for the original shows the tonality is around where it should be without requiring a boosted treble response. All Elac really needed to do was tame the distortion spikes at the crossover points.

And all they really needed to do with the original Debut was fix a few treble/tweeter and enclosure issues...but what we got was a completely different speaker that I don't think sounded as pleasing.

 

[mhmilo24]

First of all, I appreciate your experience and all the information you've gathered here about these speakers.
I would like to ask you some additional questions regarding some thoughts that I've had recently.

Has anyone had the experience to compare the Elac Uni-Fi CC U5 against a single BS U5? What can I expect from the additional low end driver? Could the composition of the CC U5 drivers cause problems in a vertical position?
I was considering moving my two BS U5s to another room, buy three CC U5 and set them up horizontally and vertically for a left-center-right configuration. Any objections as to why this could go wrong?

Eagerly awaiting your input. TY.

 

[Deego]

This is a review and detailed measurements of the Elac BS U5 "slim" 3-way coaxial speaker. It is on kind loan from a member. The U5 costs US US $856/pair everywhere so must have price control. I have read that it is designed for the European market with slimmer face and "modern" colors (black and white).

The feel, finish and looks are quite nice:

View attachment 66495

The coaxial driver above plays mid-range and woofer (or mid-woofer through mid-range and tweeter).

Nothing exciting on the back:
View attachment 66496

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.

Spinorama Audio Measurements
Acoustic measurements can be grouped in a way that can be perceptually analyzed to determine how good a speaker can be used. 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 66497

This is an unusual design. On-axis (black solid) is fairly even until about 3 kHz (where the tweeter takes over) but then we have a cycle of ups and downs. Speculating, they are diffraction interfering with the on-axis sound. Early window reflections that are at other angles, hardly show this problem (dashed blue top). There are directivity errors because of this so correction may not be easy with equalization.

We can look at the early window reflections in detail to confirm what I wrote above:

View attachment 66503

So no wonder that when we put everything together to predict the in-room response, all seems well:
View attachment 66504

Should sound good till we look at the distortion graphs with room effect filtered out:

View attachment 66535

Wow, this is quite a bit of distortion and occurring at crossover points. Is this a design problem with the coaxial driver?

We see the issue quite clearly in the context of overall frequency response:

View attachment 66515

I like to see nothing but blank space past 200 Hz and so yet we have many peaks here. Distortion is so high that I almost think it may be a measurement error but then I look at the review of Elac Adante AS-61 speaker and we have a similar issue:

That review did not use calibrated SPL levels but still, we clearly see the same rise in distortion at around 270 Hz. And another one before 2 kHz, both of which are near crossover frequencies.

This speaker makes a very good test case of whether distortion is an issue or not in absence of frequency response errors!

Our impedance and phase graph also shows a resonance point:

View attachment 66517

We kinda see the first resonance point in the CSD/waterfall as well:

View attachment 66518

You can see a trend around 300 Hz which dies down near 6 millisecond mark.

Coaxial driver brings with it good vertical directivity and we see some sign of it here:

View attachment 66519

View attachment 66520

Speaker Listening Tests
My first impression of tonality was good. Plenty of warmth due to bass response. Nice ability to play as loud as you want. But yet... the sound is not impressing me. Vocals, both female and male, sounded wrong for example.

I dial in some EQ for the elevated response above 1 kHz and that helps but still not there. I am out of normal tricks with EQ at this point as I usually have a clear guidebook of resonance peaks.

So I applying EQ to the clear distortion peaks. Reduction of level should reduce their levels as we see in the comparison graph of 86 and 96 dB above. I put those in together with my dip for my room mode:

View attachment 66522

This made a pretty good difference. Sound was more open, with more detail. I kept the Q high so that the impact on the frequency response is low (narrow notches).

At this point speakers became "good." They provide a diffused image which I like (especially since I am listening to a single channel in my reviews).

Conclusions
For a second time we see that the magic of coaxial drivers tends to be more for the eye than the ear. Distortion continues to be quite high and we have wavy output at highest frequencies. Perhaps there is no such thing as a cheap and good coaxial driver.

Or, I could be all wrong and they are fine. I tend to be much more sensitive to distortion as party of my training so what bothered me, may not bother others.

Overall, I can't recommend the Elac BS U5. If you apply some equalization as I have, I could be pushed to recommend them for their high power handling and good tonality.

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

This is the second review of the day. And on weekend no less. I demand overtime pay!!! Please donating what you can so I have something to show for it using : https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

Hey Amir,

Would your EQ be the same you'd use for the normal UB5 as well?

Where would I find your eq settings?

Thanks!

 

[Dougey_Jones]

Based on this review, I reached out to Elac, since I own a pair of UB51's which use the same driver arrangement. I spoke with Chris, their product manager and he advised that they absolutely have NOT been able to reproduce Amir's results that show distortion appearing early and with low wattage. They WERE able to get the speaker to distort with over 100 watts, but that isn't concerning to me whatsoever because I don't listen that loud.

Definitely not trying to start a kerfuffle, but thought it was worth mentioning.

 

[BYRTT]

Based on this review, I reached out to Elac, since I own a pair of UB51's which use the same driver arrangement. I spoke with Chris, their product manager and he advised that they absolutely have NOT been able to reproduce Amir's results that show distortion appearing early and with low wattage. They WERE able to get the speaker to distort with over 100 watts, but that isn't concerning to me whatsoever because I don't listen that loud.

Definitely not trying to start a kerfuffle, but thought it was worth mentioning.

Think for the distortion case there should not be a big problem in that distortion graps is dependable on used enviroment setup including software and hardware chain, so Amir's distortion graph are compareable to other "Amir distortion graphs" that used the same conditions, now if ELAC product manager is unhappy what is published here they could do something about it in they should feel free and most welcome start publish their own conditioning distortion graphs that would be compareable to other ELAC distortion graphs. When it comes to acoustic performance graphs presented as CEA/CTA2034-ANSI Spinorama's Amir is more than covered owing a new technology Klippel scanner and that performance data should normal be compareable to other sites data, so probably not ELAC product manager has any problems with the CEA/CTA2034-ANSI Spinorama's of Amir ..

 

[Dougey_Jones]

Umm, not even sure what you were trying to say there, sentence structure has me like .

In any case, I appreciate very much what Amir’s work has done for the community, but these kind of differences of opinion are inevitable when your model is the opposite of most review sites. By that I mean, not consulting/coordinating with the manufacturer and instead having people mail in their own samples for testing. I completely get that the upside is that Amir is usually getting a sample consistent with what any consumer would get, but the downside is that you run the risk of publishing findings that are harmful to brands while giving them no real opportunity to respond.

 

[BYRTT]

Umm, not even sure what you were trying to say there, sentence structure has me like .

In any case, I appreciate very much what Amir’s work has done for the community, but these kind of differences of opinion are inevitable when your model is the opposite of most review sites. By that I mean, not consulting/coordinating with the manufacturer and instead having people mail in their own samples for testing. I completely get that the upside is that Amir is usually getting a sample consistent with what any consumer would get, but the downside is that you run the risk of publishing findings that are harmful to brands while giving them no real opportunity to respond.

Amir had several times expressed he is very happy manufactures are presented here and also he like to get hands on exactly same sample as they publish in their brochure so as to kind of calibrate or quality control hardware chain and procedures, but so far he had no luck with that cooperation other than RME and few others seem represented and cooperating for their product categorys other then speaker systems, what you call a downside and harmfull to manufacture in my opinion is a strenght because i rather see performance of sales channel stuff that mister and misses avarage is offered real world than manufacture and Amir behind the facade had exchanged say up to three samples before performance will suit manufactures taste to be published here, about review can be harmful to manufacture well it looks they free to post here and deny or defend anything or be critical so they have their chance as i see it.

 

[Beave]

Based on this review, I reached out to Elac, since I own a pair of UB51's which use the same driver arrangement. I spoke with Chris, their product manager and he advised that they absolutely have NOT been able to reproduce Amir's results that show distortion appearing early and with low wattage. They WERE able to get the speaker to distort with over 100 watts, but that isn't concerning to me whatsoever because I don't listen that loud.

Definitely not trying to start a kerfuffle, but thought it was worth mentioning.

Amir's distortion measurements closely match the distortion measurements done by Soundstage at the NRC. See my post on the first page of this thread.

So I don't know what the Elac product manager is talking about.

 

[ROOSKIE]

Amir's distortion measurements closely match the distortion measurements done by Soundstage at the NRC. See my post on the first page of this thread.

So I don't know what the Elac product manager is talking about.

If I have time I can get the speakers out of storage and measure HD on them at home sometime in the next week using the same methods I use on other speakers.
I have been meaning to do this, though I have so many things that compete for my attention.
The set I have is the exact UB5 Slim set that includes the actual one Amir measured.

@Dougey_Jones take ELAC's coments with a grain of salt. There is no way they do not have measurably elevated HD with 100 watts. Nearly any small speaker will. Most floorstanders will also start to show such HD as well with 100 watts.
That 100 watts into an 85db sensitive speakers would yeild a 1meter HD test at 105db. Those speakers will show distortion artifacts you can bet on it. Whether such artifacts are out of the norms, and whether it is that big of a deal if they are is another topic of convo. I have to suspect they actually never tested HD as they described to you.

 

[Shazb0t]

If I have time I can get the speakers out of storage and measure HD on them at home sometime in the next week using the same methods I use on other speakers.
I have been meaning to do this, though I have so many things that compete for my attention.
The set I have is the exact UB5 Slim set that includes the actual one Amir measured.

@Dougey_Jones take ELAC's coments with a grain of salt. There is no way they do not have measurably elevated HD with 100 watts. Nearly any small speaker will. Most floorstanders will also start to show such HD as well with 100 watts.
That 100 watts into an 85db sensitive speakers would yeild a 1meter HD test at 105db. Those speakers will show distortion artifacts you can bet on it. Whether such artifacts are out of the norms, and whether it is that big of a deal if they are is another topic of convo. I have to suspect they actually never tested HD as they described to you.

Interested to see your distortion results.

 

[ROOSKIE]

Interested to see your distortion results.

Data has been posted here
https://www.audiosciencereview.com/...m-hd-testing-unifi-bookshelf-version-1.20285/