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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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Yes, we basically agree in that case.

FWIW, I'd say the Technics speakers being discussed here have a more classic directivity mismatch; you can see the directivity widen just where the tweeter crosses over at around 2.5KHz:

View attachment 21219
This'll be my last comment on this can of worms I've inadvertently opened (not directed at you, just a general comment about what ensued, thanks for the conversation). Yes, there is a very slight off-axis flare, but it is to a much smaller degree than the LS50 under similar conditions, which is especially peculiar considering how much smaller the radiating surface of the 5.25-inch Uni-Q is. It is as you pointed out, perhaps more "classic" in the sense of having a crossover-induced root cause rather than a mix of crossover and an unusual lack of polar pattern control in the Uni-Q midwoofer.
 

andreasmaaan

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This'll be my last comment on this can of worms I've inadvertently opened (not directed at you, just a general comment about what ensued, thanks for the conversation). Yes, there is a very slight off-axis flare, but it is to a much smaller degree than the LS50 under similar conditions, which is especially peculiar considering how much smaller the radiating surface of the 5.25-inch Uni-Q is. It is as you pointed out, perhaps more "classic" in the sense of having a crossover-induced root cause rather than a mix of crossover and an unusual lack of polar pattern control in the Uni-Q midwoofer.
Have you also heard the Technics btw? I've heard neither, and personally from the measurements I would consider both speakers to be quite well-performing although not perfect when it comes to polar response. Sure the, discontinuity in polar response is more pronounced in the KEF, but it's also much narrower in bandwidth. Hard to make a definitive call from my POV.

In any case, my much greater concern with both speakers would be that they are small passive ported speakers with port tuning frequencies up near 50Hz, and what this would mean in terms of diaphragm displacement and port compression (and resulting distortion) when fed signals with significant content below 50Hz.
 
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maty

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Can you please stop spreading this misinformation here. They are not first order filters, as is obvious looking at the graph you posted of the speaker's phase response.

I'm sure they sound much better than they would if they actually did use first order filters, of course.
Just by using a search engine you would see that Q100 and Q300 have the same type of first order filter.

KEF-Q100-crossover.jpg


And yes, with my cheap tweaks and with more mass (after the Summer), they sound much better than new. And the graphs are the graphs, made by Kimmo Saunisto, aka kimmosto (VituixCAD creator).

https://kimmosaunisto.net/Software/Software.html
 
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maty

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About KEF LS50 speakers, they need a lot of watts and, very important, at least 90 cm / 35" to the three walls. And they need feets. Over a bookshelf is a bad idea. I suspect that many of their owners did not bother to inform themselves well before making the purchase.

LS50 wireless, thanks to the internal DSP have not these great limitations. They are much better purchase than the LS50. Woofer with class D 200 watts, tweeter with class AB 30 watts.

The more interesting review, by Phil Ward:

https://www.soundonsound.com/reviews/kef-ls50-wireless
 
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maty

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To finish, the good KEF coaxial is the 5.25" and not the 6.5" (Q300). The second does not have the same magic sound, aka coherence, dispersion. The sound is more like traditional speakers without coaxial. But they are BIG and the buyers bought it without having informed, as is too common in opinion makers in these times.
 
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Frank Dernie

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I am slightly mystified.
The angry tone of this thread encouraged me to look at the lateral directivity of a few well regarded loudspeakers and I am struggling to find particular fault with the LS50 compared to any I have looked at so far including those where directivity is a stated priority of the manufacturer?????
The difference between the Technics and Kef look minuscule to me given the normally much greater magnitude of difference in this parameter in Stereophile’s review, which is the easiest place for me to check.
 

andreasmaaan

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Just by using a search engine you would see that Q100 and Q300 have the same type of first order filter.

View attachment 21224

And yes, with my cheap tweaks and with more mass (after the Summer), they sound much better than new. And the graphs are the graphs, made by Kimmo Saunisto, aka kimmosto (VituixCAD creator).

https://kimmosaunisto.net/Software/Software.html
Glad that you’re happy with your tweaks.

The electrical filter is first order but the phase response graph clearly shows that the acoustical filter is not. Sorry, that’s just how it is.

I don't have a complete set of measurements of the Q100 but there is a very comprehensive set of measurements of the Q300 here (sorry, German only but if you don't speak German you should be able to translate it quite easily).

The key measurement on that website is the step response:

1549104486171.png


As can be clearly seen, the tweeter is connected with negative polarity and the woofer is connected with positive polarity. In other words, the polarity between the woofer and tweeter is opposite.

If the acoustic filter really were first order, connecting the drivers in opposite polarity would result in a null at the crossover frequency. The fact that the drivers are connected with opposite polarity proves that each filter slope must be (close to) 90° out of phase, or in other words, 2nd order.

Indeed, approximately 2nd order filter slopes are precisely what we see when we look at the measured magnitude response of the two drive units + crossover (notwithstanding some poorly suppressed cone break-up in the 5-12KHz range of the woofer):

1549104797611.png
 

andreasmaaan

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I am slightly mystified.
The angry tone of this thread encouraged me to look at the lateral directivity of a few well regarded loudspeakers and I am struggling to find particular fault with the LS50 compared to any I have looked at so far including those where directivity is a stated priority of the manufacturer?????
The difference between the Technics and Kef look minuscule to me given the normally much greater magnitude of difference in this parameter in Stereophile’s review, which is the easiest place for me to check.
I hope you don't feel the angry tone is coming from me? I agree with you that both speakers measure very well and I'd call their imperfections in terms of directivity control quite minor compared to many other speakers.
 

maty

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I read the German review years ago and it is in my bookmarks. It is well known that the tweeter is in opposition, something that the purists do not like but what is important is the result, and it is good. The frequency response is more flat that LS50 (with more complex crossovers).

But you said: Can you please stop spreading this misinformation here. In any case, it would be incomplete. Hence, afterwards I have detailed the known problems of the LS50.

Other problem with KEF Q100 is the bass re-reflex. It has a big peak between 1.1 - 1.3 kHz. Tweaked by me too, voices more clear.

KEF-Q100-frequency-bass-reflex.png


Years ago, with the Würth 150 kHz ferrite it has more and better bass. It was trial and error. I still do not understand why it improves it, but the improvement is there. Woofer with greater slope? I do not know. But the new Q150:

https://www.kefdirect.com/q150-bookshelf-speaker.html

Uni-Q sound taken to the next level

With the addition of the damped tweeter loading tube providing a gentle termination of sound produced from the back of the tweeter, lower treble performance is improved dramatically and a new low-distortion inductor on the crossover provides cleaner bass.

To optimize the resolution and purity of the Q Series bookshelf speakers, the Uni-Q driver has been repositioned to the center of the cabinet to reduce unwanted internal resonance and adds refinement to their sonic clarity and detail.
CFD Designed Port

Featuring a Computational Fluid Dyanmics (CFD) port design with the port repositioned to the rear of the speaker, clarity is improved by reducing the audibility of the midrange leakage through the port. The geometry of the ports have been tuned to minimize turbelence at higher levels resulting in a reduction in port noise and less LF compression.
My tweaks have some years. The added mass (substantial sound improvement), from Summer 2018. Like so many speakers, they need furniture with greater mass, but manufacturers save on the furniture and, consequently, on logistics.
 
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maty

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https://www.stereophile.com/content/kef-ls50-anniversary-model-loudspeaker-measurements



Fig.8 KEF LS50, step response on HF axis at 50" (5ms time window, 30kHz bandwidth).

Turning to the time domain, the LS50's step response on its tweeter axis (fig.8) indicates that the tweeter is connected in negative acoustic polarity, the woofer in positive polarity. However, the smooth integration of the decay of the tweeter step into the start of the woofer step implies optimal crossover design and correlates with the excellent integration of their outputs in the frequency domain seen in fig.3...
 

andreasmaaan

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I read the German review years ago and it is in my bookmarks. It is well known that the tweeter is in opposition, something that the purists do not like but what is important is the result, and it is good.
I’m not interested in what the purists like, but I am interested in the acoustic slope of the filter, which is clearly 2nd order (a better choice than first order IMO).

And yes, the LS50 also seems to use 2nd order filters.
 

Ilkless

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Have you also heard the Technics btw?
I've had extensive experience with the LS50. The discontinuity is highly audible on the LS50, I called a peak at 2kHz - in multiple listening rooms - even before any measurements came out. The elevated listening window response and off-axis discontinuity contributes to a subjective sense of an obscuring sheen on brass, accentuates sibilance and emphasises hiss. Nonetheless I do not regard any sighted listening impressions as binding or relevant to evaluating the performance of a loudspeaker.

I have not heard the Technics because Panasonic doesn't intend to distribute it in my territory, but if you are looking for people who have, there were a couple on DIYAudio whom I turned onto these speakers, who have also heard the LS50 and compared it.

I've heard neither, and personally from the measurements I would consider both speakers to be quite well-performing although not perfect when it comes to polar response. Sure the, discontinuity in polar response is more pronounced in the KEF, but it's also much narrower in bandwidth. Hard to make a definitive call from my POV.

In any case, my much greater concern with both speakers would be that they are small passive ported speakers with port tuning frequencies up near 50Hz, and what this would mean in terms of diaphragm displacement and port compression (and resulting distortion) when fed signals with significant content below 50Hz.
On the bandwidth of polar discontinuity, the KEF spans 800Hz to 5kHz (over 2 octaves), if we include the weird early beaming and widening of the midwoofer below the crossover. The LS50 has a dramatic dip beginning at 800Hz centred at 1.3kHz that deepens off-axis, and causing 2kHz to be relatively peaked when dispersion broadens again.

The Technics doesn't suffer from the 1.3kHz beaming and broadening, it has substantially smaller variations spread from 3-9kHz (about the same octaval bandwidth). I'd personally take smaller variations higher up in the range than severe discontinuities in the upper midrange and low treble.

Another interesting thing is the unusual port designs both have. The LS50 has semi-permeable port walls, the Technics apparently has a port that faces a "padded partition" internally and so there is no port resonance in the midrange that plagues some speakers (including the JBL LSR705 at 800Hz).

edit: yes, porting might be an issue, but it isn't inherent to coaxial speakers, but affects all speakers of that size class and tuning. Though you have a point insofar as excursion of the midwoofer modulating tweeter output.

edit2: might I suggest that @amirm or someone else spin off this coaxial discussion into a separate thread? It is a derailment of the original thread but I think the discussion on the properties of coaxial drivers is pretty good.
 
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maty

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@Ilkless

What do you think about KEF Q100? And vs LS50.

KEF Q100




KEF LS50



Btw, Q100, new sound very bad, without bass. They need very long burn-out. Mine, 200 hours. My hypothesis is that it is due to a very rigid suspension to reduce the vibrations that transmits the coaxial to the furniture. Still insufficient, the furniture needs more mass!
 

andreasmaaan

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edit: yes, porting might be an issue, but it isn't inherent to coaxial speakers, but affects all speakers of that size class and tuning. Though you have a point insofar as excursion of the midwoofer modulating tweeter output.
There's that, sure. But I also had in mind simply the nonlinear distortion such a small port / high tuning frequency has on the woofer itself. And yes, this is an inherent drawback of any small passive ported speaker (personally I would prefer to see a passive radiator on a speaker of that size).
 

maty

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Just now, in diyaudio forums, KEF LS50 thread:

https://www.diyaudio.com/forums/multi-way/218281-kef-ls50-post5685193.html

I am not sure what "smooth" sounding speaker means, but I know how the original LS 50 sounds and the one with the upgraded crossover from Ton-Feile. And there is no comparison, that the Ton-Feile version sounds so much better (clearer, more true), which is no wonder when you look at the frequency response.
But for DIYers I would not buy a LS50 to mod it, but choose another option and build a new speaker right away. The user Ton-Feile has created a speaker called "Tafal", which outperforms the LS50. Another great option is the "Duo DXT" or some of the derivates which came over the time like "DXT Mon" and others. All three mentioned examples built by very experienced DIYers, who are all also active in some kind of other in audio / sound for a professional living. They develop speakers not to a market or price point, but to deliver the best results possible they have in mind and one can achieve.
[German] http://www.frank-landmesser.de/bau_ls50.html

-> http://www.frank-landmesser.de/bau_ls50_aufbau.html

http://www.hifi-forum.de/viewthread-104-26095-2.html



Measurements: http://www.hifi-forum.de/viewthread-104-26095-2.html#60

More flat response but there are a problem: true 83 dB/W/m -> 81 dB/W/m. They need amp with more watts!!!
 
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Yes, my London system was Devialet 120 plus LS50s with SAM. Sounded wonderful in most respects but quickly ran out of dynamic range in the low bass.
Agree on the LS50 being a bit lacking in the low bass department (as one would expect considering their diminuitive size) but could it be that the low output of the 120 was a contributing factor?

I used to own a Devialet 120 + KEF Reference 1 and found the amp struggled to drive them at lower frequencies when the volume got even remotely loud. Devialet loaned me a Devialet 200 for a few weeks and it was *significantly* better. The Devialet range are cheekily specced at 6-ohms - so a Devialet 120 would be 90W into the LS50s 8-ohms.
 

Dialectic

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Agree on the LS50 being a bit lacking in the low bass department (as one would expect considering their diminuitive size) but could it be that the low output of the 120 was a contributing factor?

I used to own a Devialet 120 + KEF Reference 1 and found the amp struggled to drive them at lower frequencies when the volume got even remotely loud. Devialet loaned me a Devialet 200 for a few weeks and it was *significantly* better. The Devialet range are cheekily specced at 6-ohms - so a Devialet 120 would be 90W into the LS50s 8-ohms.
Based on the cone excursion I witnessed while pushing the LS50s with organ music, I think it was the speakers running out of low end and not a problem with amp grunt. In any event, I'm going to add multiple subs soon and cross the LS50s over using "le configurateur" circa 100 Hz. Any lack of low end, whether from the speakers giving out or the amp running out of juice, will no longer be a problem.
 
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