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What's the best passive (and preferably floorstanding) speaker one can find for $2,500 or less?

Ilkless

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I've seen the measurements and have not seen the elevated response described. Nor do I think the more "evidence-based" Technics monitors measure significantly better, except in the low end (because they are larger).

fr_listeningwindow.gif


This was the listening window measured at NRC. Don't you think +3dB from 2-5kHz of the direct sound represents a speaker that's far from "state-of-the-art"? It gets even worse off-axis.

Moreover, this is corroborated by Stereophile's data

1212KEF50fig4.jpg


Note the peak at 2kHz again (classic directivity mismatch), matching the NRC graphs, though the scale on the Stereophile graphs make it seem more benign than it actually is. In contrast, the Technics I mentioned has seamless dispersion off-axis throughout the crossover region at 2kHz:

1215TC700fig4.jpg


The top-octave peaks are actually artefacts arising from using off-axis curves normalised to the on-axis curve. Dips appear on-axis, but fill in to flat right away off-axis. The normalisation represents this filling in as a peak. It is psychoacoustically-innocuous, and using a measurement method like spatial averaging of the measuring window would be more representative, greatly reducing the dip. Earl Geddes explains it in the discussion on page 724 of the linked thread.

This discussion on directivity is not theoretical. It relates to sound in-room. As Toole writes:

This is information that is almost never known by people offering opinions about the audible effects of these reflections, yet it is known to be critical to the listening experience. If the spectra of the direct and reflected sounds are significantly different, the reflections are likely to be more noticeable, from subtle timbral effects up to a premature breakdown of the precedence effect, at which point listeners may be aware of two simultaneous sound images, one located at the loudspeaker and one located at the point of reflection. This is obviously not good. Over the years this is likely a factor in listeners rating loudspeakers with uniform directivity more highly than those with uneven directivity. Wide dispersion seems to be good, but especially if it is uniform with frequency and the spectra of the reflections is not substantially altered. Hundreds of loudspeakers auditioned by hundreds of listeners in double-blind evaluations have demonstrated this; it is monotonously predictable.

What is perplexing for me is a surprising lack of evidence used to substantiate the defense of the LS50 - especially on ASR of all places - and that people whose listening experience have been enhanced by relying on some very sophisticated audio engineering ironically cast aspersions upon using the same parameters their equipment excel in to evaluate cheaper equipment.
 
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Dialectic

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fr_listeningwindow.gif


This was the listening window measured at NRC. Don't you think +3dB from 2-5kHz of the direct sound represents a speaker that's far from "state-of-the-art"? It gets even worse off-axis.

Moreover, this is corroborated by Stereophile's data

1212KEF50fig4.jpg


Note the peak at 2kHz again (classic directivity mismatch), matching the NRC graphs, though the scale on the Stereophile graphs make it seem more benign than it actually is. In contrast, the Technics I mentioned has seamless dispersion off-axis throughout the crossover region at 2kHz:

1215TC700fig4.jpg


The top-octave peaks are actually artefacts arising from using off-axis curves normalised to the on-axis curve. Dips appear on-axis, but fill in to flat right away off-axis. The normalisation represents this filling in as a peak. It is psychoacoustically-innocuous, and using a measurement method like spatial averaging of the measuring window would be more representative, greatly reducing the dip. Earl Geddes explains it in the discussion on page 724 of the linked thread.

This discussion on directivity is not theoretical. It relates to sound in-room. As Toole writes:



What is perplexing for me is a surprising lack of evidence used to substantiate the defense of the LS50 - especially on ASR of all places - and that people whose listening experience have been enhanced by relying on some very sophisticated audio engineering ironically cast aspersions upon using the same parameters their equipment excel in to evaluate cheaper equipment.
I never said the LS50 was state of the art, and the elevated response is not that elevated. You are making much of a very minor design flaw (or perhaps audiophile design choice). It's a good thing that my main speakers have perhaps the most uniform dispersion of any speakers available today.
 

Sancus

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Given that hearing loss at 3-6khz tends to happen first with noise exposure, I wouldn't be too surprised if there's a large population of people who actually like a slightly elevated response in that area.
 

Ron Texas

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There is a strong indication that the 2-5khz elevation was intentional. It may be to offset hearing loss or it may have to do with how the sound is perceived in a typical room.

Go look at a bunch of on axis frequency response charts at Stereophile and in that context the LS50 looks flat.

This discussion reminds me of a guy who said "Honda's and Toyota's are great, everything else is crap." I had a VW at the time. He was repeatedly fired from a series of jobs for being so brash.

I thought the OP wanted floor standing speakers which is why I did not recommend the LS50's even though I love mine.
 

andreasmaaan

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Note the peak at 2kHz again (classic directivity mismatch), matching the NRC graphs, though the scale on the Stereophile graphs make it seem more benign than it actually is.

Are you talking about the LS50 when you say "classic directivity mismatch"?

I'm not out to defend the LS50 in particular, it measures well but isn't exceptional. But there is no classic directivity mismatch; the LS50 uses a coaxial driver in which the woofer cone provides a waveguide for the tweeter, controlling directivity at/above the crossover point and actually resulting in fairly uniform directivity between the woofer and tweeter.

This is borne out by the off-axis measurements, in which we see the tweeter's directivity actually narrow in relation to the woofer's (note the xover point is 2.2KHz, exactly where directivity begins to narrow). This is the opposite of a "classic" mismatch, and indeed an effect that is likely to partially mitigate the tweeter's slightly peaky response at the bottom of its passband. The real (slight) issue with this speaker's performance is the peak in the woofer's output just below the xover point, at around 2KHz, and the dip in the woofer's response just below that (1-1.5KHz):

1549030183943.png


Or from Stereophile (normalised to on-axis response):

1549030335031.png


This is anechoic measurement. Looking at off-axis response I assume that LS50 was designed without directivity in mind. So in room it would be rather worse.

See the graphs above. Directivity is fairly well-controlled in this speaker and is IMHO certainly something the designer kept in mind.
 
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Ron Texas

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Somebody's coffee got spiked.
 

Ilkless

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Probably you are right. I was looking on 45-75 degrees off-axis.

As was I.

Are you talking about the LS50 when you say "classic directivity mismatch"?

I'm not out to defend the LS50 in particular, it measures well but isn't exceptional. But there is no classic directivity mismatch; the LS50 uses a coaxial driver in which the woofer cone provides a waveguide for the tweeter, controlling directivity at/above the crossover point and actually resulting in fairly uniform directivity between the woofer and tweeter.

This is borne out by the off-axis measurements, in which we see the tweeter's directivity actually narrow in relation to the woofer's (note the xover point is 2.2KHz, exactly where directivity begins to narrow). This is the opposite of a "classic" mismatch, and indeed an effect that is likely to partially mitigate the tweeter's slightly peaky response at the bottom of its passband. The real (slight) issue with this speaker's performance is the peak in the woofer's output just below the xover point, at around 2KHz, and the dip in the woofer's response just below that (1-1.5KHz):

View attachment 21172

Or from Stereophile (normalised to on-axis response):

View attachment 21173



See the graphs above. Directivity is fairly well-controlled in this speaker and is IMHO certainly something the designer kept in mind.


fr_456075.gif


See the 45-75° curves.

KEF%20LS50%20H%20Freq%20Resp%20Plot%20Q1.png


Princeton's 3D3A measured similar issues. The tweeter radiation pattern is definitely broad relative to the woofer's, regardless of the waveguide loading. Note how the peak becomes increasingly-pronounced off-axis. For what's its worth, I've heard them extensively before any measurements were made in the press and the anomalies were plainly audible and I could pinpoint it to 2kHz. It is a directivity mismatch as clearly demonstrated.
 

andreasmaaan

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Princeton's 3D3A measured similar issues. The tweeter radiation pattern is definitely broad relative to the woofer's, regardless of the waveguide loading. Note how the peak becomes increasingly-pronounced off-axis.

Are we looking at the same graph here? The tweeter’s dispersion is clearly narrower than the woofer’s around the crossover point (2.2KHz).

EDIT: ...unless the true crossover point is not the specified 2.2KHz.
 
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Ron Texas

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As was I.
Princeton's 3D3A measured similar issues. The tweeter radiation pattern is definitely broad relative to the woofer's, regardless of the waveguide loading. Note how the peak becomes increasingly-pronounced off-axis. For what's its worth, I've heard them extensively before any measurements were made in the press and the anomalies were plainly audible and I could pinpoint it to 2kHz. It is a directivity mismatch as clearly demonstrated.

Why don't you write KEF a letter and ask them for an explanation, or read their white paper on design and report back to us? Better yet, send them your resume and see if they hire you to head up their engineering team.

Just because you heard something or think you heard something and then go searching for a possible measurement as the cause does not establish causation for what you might have heard. Whatever it is, it isn't hurting the music. Too many people with a lot of hi-fi experience love these speakers Some abnormality in the measurements does not establish "unacceptable engineering" or a plainly audible classic mismatch. Perhaps you should be thinking about why so many folks love these speakers in spite of this abnormality, or because of it. It isn't marketing.

I hope you realize by now that a lot of folks own LS50's and your style (and not the data) is annoying the hell out of them. Just go ahead and call LS50's crap and move on. Besides, the OP wants stand mounts and an extensive discussion of a possible oddity in one popular stand mount speaker is hardly on topic.
 

Ilkless

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Are we looking at the same graph here? The tweeter’s dispersion is clearly narrower than the woofer’s around the crossover point (2.2KHz).

EDIT: ...unless the true crossover point is not the specified 2.2KHz.

No, it is indeed 2.2kHz. Someone else measured it. There is a dip between 1-2kHz. Usefully, the guy that made those measurements equalised the dip to flat and measured off-axis:

amp-horiz-winkel-mit-eq-20khz_327339.jpg


There is still mismatch. The other question is why would a midwoofer with such a small radiating diameter, on multiple independent measurements have a dip that deepens off-axis at a frequency where it should not beam that drastically. Nonetheless, I do not regard this acceptable behaviour for a passive minimonitor that is $1000 even on sale, so the praise and hype it gets is puzzling.
 

Ron Texas

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Nonetheless, I do not regard this acceptable behaviour for a passive minimonitor that is $1000 even on sale, so the praise and hype it gets is puzzling.

Perhaps you are puzzled because the praise is not hype and the LS50 performs. $1000 is not big bucks in this game either. I might understand your outlook if these cost $3000. There might be something in the measurements, but you are turning a molehill into a mountain.
 
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Dialectic

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Perhaps you are puzzled because the praise is not hype and the LS50 performs. $1000 is not big bucks in this game either. I might understand your outlook if these cost $3000. There might be something in the measurements, but you are turning a molehill into a mountain.
Yes, they measure better than anything made by, e.g., B&W, and the sound of the LS50s is very subjectively pleasing. I look forward to EQing the shit out of mine and leashing up some subs to them.
 

andreasmaaan

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No, it is indeed 2.2kHz. Someone else measured it. There is a dip between 1-2kHz. Usefully, the guy that made those measurements equalised the dip to flat and measured off-axis:

amp-horiz-winkel-mit-eq-20khz_327339.jpg


There is still mismatch. The other question is why would a midwoofer with such a small radiating diameter, on multiple independent measurements have a dip that deepens off-axis at a frequency where it should not beam that drastically. Nonetheless, I do not regard this acceptable behaviour for a passive minimonitor that is $1000 even on sale, so the praise and hype it gets is puzzling.

It is curious behaviour, sure. I don't think it looks terrible compared to many speakers in that price range (or any price range), but it's not ideal.

Nevertheless, as per my original point, it's actually the opposite kind of directivity mismatch to that which would be described as "classic".
 

Frank Dernie

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Yes, they measure better than anything made by, e.g., B&W, and the sound of the LS50s is very subjectively pleasing. I look forward to EQing the shit out of mine and leashing up some subs to them.
There is a Devialet SAM profile for the LS50 you have probably tried.
The LS50s are absolutely stunning IME though mine are not in use just now I had them in my study and the ProAc EBS are connected in there now.
They do need lots of power and my guess is that those who find fault have an inadequate amp.
 

Blumlein 88

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There is a Devialet SAM profile for the LS50 you have probably tried.
The LS50s are absolutely stunning IME though mine are not in use just now I had them in my study and the ProAc EBS are connected in there now.
They do need lots of power and my guess is that those who find fault have an inadequate amp.
I've found the same thing. They need more power than some people realize. They sound much better with a beefy amp behind them.
 

Ron Texas

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Yes, they measure better than anything made by, e.g., B&W, and the sound of the LS50s is very subjectively pleasing. I look forward to EQing the shit out of mine and leashing up some subs to them.

I have a sub and it made a big difference. The only EQ I am using right now is for the sub and that does make a difference. I identified a peak at 160 hz, but when I EQ'ed it, I could not hear a difference. That might get revisited.
 
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