Elac Uni-Fi 2.0 Review (bookshelf speaker)

[IvanT]

I really hate admitting when I'm wrong, (that's what objectivity is supposed to do,) but I CAN replicate what @amirm experienced at 585hz when I play a single tone and raise the volume. I experienced it at what I would consider a reasonable volume for a speaker of this size and price. (I won't go into specifics so as not to pretend this was a well-controlled test, but let's just say it was below the 0dB "reference level" on my AVR so I'm guessing BELOW 85dB-105dB at my listening position about 12ft away.) My AVR is the NAD T778 acting as a preamp. My power amp is the Parasound A52+ which is rated at 225wpc @ 4 ohms. It's possible I was pumping out more wattage than the speaker is rated for at that dB and that frequency. I don't know since I'm not measuring the wattage. I just know it's at a volume I would normally play my speakers in my small apartment, so not crazy loud compared to some other guys with dedicated theaters.

When I made my review of the UB52, I complained that I didn't like something about the highs coming from the tweeter. Having heard what I just heard, I'm wondering if it was the resonance from the aluminum-cone midrange making higher frequency sounds which I might have mistaken as coming from the tweeter.

I'll leave it to the engineers to discuss. I'm really just a dude who likes speakers who wishes I understood as much as these guys.

Joentell, when you say "single tone", was this a 585 hz tone? I want to try this with my UF52s to see if I can get the same.

 

[joentell]

Joentell, when you say "single tone", was this a 585 hz tone? I want to try this with my UF52s to see if I can get the same.

Yes, 585hz using a test tone generator app.

 

[IvanT]

Joentell, when you say "single tone", was this a 585 hz tone? I want to try this with my UF52s to see if I can get the same.

By the way, the A52+ gives 225 Wpc at 8 ohms for 2-channel operation and 350 Wpc at 4 ohm. You might have been above the ELac's rating if you were close to o dB.

 

[joentell]

By the way, the A52+ gives 225 Wpc at 8 ohms for 2-channel operation and 350 Wpc at 4 ohm. You might have been above the ELac's rating if you were close to o dB.

I don't know how much wattage I was pumping out but I do have 5 channels connected which is rated at 225w, but they weren't all driven at the same time.

I think what's important is whether it happens at levels most people would expect to use them. I would have to say yes, but I'm curious to see what others find.

 

[bokolobs]

I really hate admitting when I'm wrong, (that's what objectivity is supposed to do,) but I CAN replicate what @amirm experienced at 585hz when I play a single tone and raise the volume. I experienced it at what I would consider a reasonable volume for a speaker of this size and price. (I won't go into specifics so as not to pretend this was a well-controlled test, but let's just say it was below the 0dB "reference level" on my AVR so I'm guessing BELOW 85dB-105dB at my listening position about 12ft away.)...

You got one important part of science right–changing your conclusion reporting new observations in the face of new evidence. Kudos @joentell ! The word "science" is in the middle of the name of this site, so a lot of us expect a semblance of the scientific method to be at the heart of the reviews, which is true to some extent. The implicit hypothesis is that a particular speaker will hit the ideal targets. Then experiments are performed, data collected, conclusions are made. As the others already mentioned, there should be some sort of control and multiple samples should have been tested. Most of all, when the same methods, conditions, and experiments are done elsewhere, it should give the same data to match the conclusions. We turn a blind eye to the shortcomings most of the time because we know and understand the limitations, as well as enjoy the ensuing debates. Most of us cannot perform the experiments needed to make reasonable conclusions. And in this way, this site provides a very noble service to the audio community. But, and I say this with all due respect to everyone here, I think saying that this is merely speaker "testing" is a cop out. Might as well change the name of the site to audiotestreview.com.

 

[Laserjock]

Should we now have a “585” test at increased volume for every speaker?
Is it just a physical issue with a component resonating at this frequency in this speaker?

 

[EB1000]

Ruth Bader Ginsburg seems to like them, claiming they are amazing:

 

[boselover61]

Ruth Bader Ginsburg seems to like them, claiming they are amazing:

He claims anything is amazing as long as he gets paid for it

 

[HARMAN]

OK, it's taken a while, but here are my findings.
I sent them to Amir directly a week or so ago so he could take a look, and now I'm haring them with the group directly.
I had to wait to get the sample Amir had tested, since he had already returned it to the original owner. I contacted that owner to arrange to have it shipped to me , along with the other of the pair, once he received it. Since Amir had not noted the serial number I made sure the owner marked which one was the sample that was returned from Amir.
I also asked that he give it another listen to compare to the retained speaker, in light of Amir's findings
His response was that maybe, just maybe he heard something different, but wasn't totally sure that it wasn't just bias from knowing Amirs findings.

I have now studied the speaker samples; the one you tested, the other sample from the customer, and a number of samples I had in my lab.

These are my findings.

1/ The sample you tested has a trim ring that is slightly raised in a few places. This lifted it in such a way that it could potentially vibrate.
2/ It’s pair showed no such signs. The trim ring was properly seated.
3/ In my initial listening and testing sessions, I found no evidence of vibration (Rattling) during standard sweep testing or odd noises while listening to the test track you identified. These tests were done at normal test level and listening level.

In light of your comments about listening at high levels, and using an extremely powerful amplifier, I brought out an amplifier rated at 300W into the impedance of the speaker at the frequency in question.
I first listened with the test track and adjusted the level to just reach clipping point during that track segment. I could not hear the noise. I then raised the gain to push the amplifier into severe clipping, to the point that on the loudest vocals the voice was heavily modulated and distorted due to clipping. I could still not detect the noise you described. Nor could my colleague.

I then went to do sweep testing from an oscillator to try and zero in on that frequency range. At normal sweep testing levels I could not detect any odd noise.

However, if I increased the level to just below clipping on this test amplifier, in this case at 80W/5 ohms, I now heard a very noticeable rattle/vibration.
It was a little more obvious on the sample with the raised trim ring, but was still evident on the pair sample.

After a short while I went to push on the midrange cone to see if it might be rubbing on a potentially off-center tweeter, but was surprised that the midrange cone was very hot. The midrange driver has a voice coil wound on an aluminum former bonded to an aluminum cone. This gives quite a good heat transfer from coil to cone.
I let it cool down, and repeated the experiment. Same result. In just a matter of 10-15 seconds the cone became very hot.
This is a lot of power being dissipated in the driver. On music I have never noticed that cone getting warm, despite playing at loud levels even in show conditions.

Once I backed down the level a few dB, the vibration noise went away.

It seems that the vibration happens at high level. But this level is way beyond the rated power level of this speaker. Let me explain how we do our power testing and how it relates to the power contained in music rather than sine waves.

When we establish power rating on a speaker, we test with IEC noise (pink noise filtered to a limited bandwidth to represent a music spectrum, with a crest factor of 6dB) . Let’s say that we want to test for a Max power of 100W. We adjust the long term average power to 25W (6dB crest factor) equivalent to a 100W amplifier just at clipping. We then run the speaker for 96 hours at this level. This is severe. Over such a long period the speaker gets very hot, the drivers being much too hot to touch. After cooling down, we retest the speaker. It must pass the standard test limits we put on a production speaker.
We then increase the level to 33W and run for a further 24 hours. it must survive and shift its specs just moderately. After that we turn up the level to destruction point. The speaker must not catch fire.

This is a very severe overall test. Much more severe than regular music represents, and much more severe than the AES/IEC long term power handling test spec.

In the case of the UNIFI, the max power rating is 140W. The testing we do allows for up to 25 or 33W of continuous power. In testing this sample I had to put in 2-3 times that continuous power level, centered at the frequency of the issue, to excite the noise, and on music I tested at 2 times the max power level and just below clipping level of the amplifier and heard nothing. Even when running into gross clipping I only heard the effect of gross clipping of the amplifier

It seems that the level you were testing at was far in excess of the max power rating of the speaker. This could account for the comments from other listeners that have not heard the sound.

I will put the speaker back together, and get it, or a fresh sample, returned to you to continue your evaluation. I will also track down the rattle that I did hear when the speaker was grossly overdriven and report back.

Regards

Andrew Jones
ELAC

Hi what is the conclusion from your test?

 

[Music1969]

Where are we at with this lol

Is Amir re-testing?

 

[boselover61]

Where are we at with this lol

Is Amir re-testing?

I see no reason for him to tbh. People in this thread already indicated this is a problem with the speakers build quality

 

[HARMAN]

Amirm
" I guess it is possible this one speaker sample has an issue in which case I encourage Elac to try to replicate this problem and let us know what is going on."
it's all of the line or one speaker?

 

[boselover61]

Amirm
" I guess it is possible this one speaker sample has an issue in which case I encourage Elac to try to replicate this problem and let us know what is going on."
it's all of the line or one speaker?

Not sure but I saw someone stating Elac's already making a better built version of this speaker so I'm assuming this issue affect all current speakers.

 

[RobS]

@amirm there has been concern elsewhere that your measurement setup isn't properly grounded, like your AP analyzer and the Klippel. An ungrounded setup would yield poor measurement results. Can you confirm please?

 

[lizhuoyin]

@amirm there has been concern elsewhere that your measurement setup isn't properly grounded, like your AP analyzer and the Klippel. An ungrounded setup would yield poor measurement results. Can you confirm please?

Can you elaborate on the "ungrounded" claims?

 

[BYRTT]

@amirm there has been concern elsewhere that your measurement setup isn't properly grounded, like your AP analyzer and the Klippel. An ungrounded setup would yield poor measurement results. Can you confirm please?

Yep a grounded UMIK-1 setup and some nice 200-300dB vertical scales could maybe make the world happier.

 

[amirm]

@amirm there has been concern elsewhere that your measurement setup isn't properly grounded, like your AP analyzer and the Klippel. An ungrounded setup would yield poor measurement results. Can you confirm please?

I have not seen such claims. The AP analyzer is NOT used in any speaker testing or listening anyway. For electronics testing where it is used, the AP analyzer inputs are floating even in unbalanced connections. If I see mains interference -- which is very clear in the FFT shown in the dashboard -- I play with grounding the analyzer in various ways to lower or eliminate such factors. But again, AP is not used for speaker testing and even if it were, and I had not taken such precautions, it would not matter in measurements of speakers where noise floor is hugely higher.

In addition, the Klippel analyzer is programmed with extra set of sense inputs that measure the output of the amp and equalize it to the source signal. This means any frequency response errors created in the chain are removed (in software).

So no, there is no such merit to any argument like this.

 

[RobS]

I have not seen such claims. The AP analyzer is NOT used in any speaker testing or listening anyway. For electronics testing where it is used, the AP analyzer inputs are floating even in unbalanced connections. If I see mains interference -- which is very clear in the FFT shown in the dashboard -- I play with grounding the analyzer in various ways to lower or eliminate such factors. But again, AP is not used for speaker testing and even if it were, and I had not taken such precautions, it would not matter in measurements of speakers where noise floor is hugely higher.

In addition, the Klippel analyzer is programmed with extra set of sense inputs that measure the output of the amp and equalize it to the source signal. This means any frequency response errors created in the chain are removed (in software).

So no, there is no such merit to any argument like this.

Thank you Amir for responding.

How do you go about measuring speaker distortion then? That seems to be challenging and a pain to do since you are in a non-anechoic environment, I assume. You can't just stick a mic at the woofer.

I've tried to find information on how you have your speaker measurement room setup but haven't found a thread. Is it sound proofed, how many and what kind of microphones do you use?

 

[amirm]

How do you go about measuring speaker distortion then? That seems to be challenging and a pain to do since you are in a non-anechoic environment, I assume. You can't just stick a mic at the woofer.

It is almost that simple! The only catch is that you want contributions from all the drivers so you don't want the mic that close. I set it at 1/3 of a meter on tweeter/reference axis. Of course you need a very low distortion microphone.

I've tried to find information on how you have your speaker measurement room setup but haven't found a thread.

I have written an article on this for print magazine. I need to format it for online use and will do that soon.

 

[Music1969]

I see no reason for him to tbh. People in this thread already indicated this is a problem with the speakers build quality

Noted but I thought this unit Amir measured was faulty so a re-test of different unit could clarify this