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KEF Q100 Speaker Review

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amirm

amirm

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thanks very much! However the link does not include the postal panther. I hope it doesn't indicate our leader is going postal!
He is there. Go to follow on posts....
 
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Anyone sending the new Q150 or Q350 for Amir? It would be great to see how much better the new version really is. While the R-serie is superior we can´t argue that the Q-range is still sold lot more as being entry level model. I would also like to see the measured data when port bungs are being used as there is persons claiming they sound MUCH better when used with bungs (Q350 especially).
 

maty

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Justice for Kef Q100, by Jokerbre
https://www.diyaudio.com/forums/multi-way/352846-justice-kef-q100.html

[ KEF Q100... yes i know that one. Do you really know that speaker?

Do you know that feeling when you see something, something that gets under your skin. Gently crawl under the skull and torture brain at night when you lie down, then gently whisper that driver it's the chosen one.

This is exactly how I felt when I saw the construction and engineering that was put into this driver. But the comments and various reviews indicated that it was just an ok speaker, and those things turned me off from buying it... ]

[ Made new enclosures, new measurements in new enclosures and these are the results.
Mic is Umik-1 ]

Optimized

New crossover

KEF-Q100-new-crossover-by-Jokerbre.png



On axis

KEF-Q100-new-crossover-on-axis-by-Jokerbre.png



Of axis 0-10-20-30-40-50

KEF-Q100-new-crossover-Of-axis-0-10-20-30-40-50-by-Jokerbre.gif



3 db/oct

KEF-Q100-new-crossover-on-axis-3dB-octave-by-Jokerbre.png



6 dB/oct

KEF-Q100-new-crossover-on-axis-6dB-octave-by-Jokerbre.png
 
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maty

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KEf Q100 driver in new enclosure, by Jokerbre
https://www.diyaudio.com/forums/multi-way/352846-justice-kef-q100-post6165726.html

KEF-Q100-DIY-by-Jokerbre.jpg


[ Enclosure is made from MDF 19mm, front baffle 22 mm, internal bracing glued with elastic glue. Front baffle is glued to enclosure with soft polyurethane glue that is used for gluing car windshield. Driver is coupled with back and side walls... ]

Clarified, optimized... to see inside details

KEF-Q100-DIY-inside-by-Jokerbre-optm.jpg
 
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maty

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https://www.diyaudio.com/forums/multi-way/352846-justice-kef-q100-2.html#post6165759

[ In my opinion, this speaker sounds better than the LS50. But...

As with the LS50 as well as the R300 also with this speaker, I have problems with two things. The first is the ferrofluid in the tweeter. The tweeter sound is great but it can be better. I have repeatedly found that removing ferrofluids from the tweeter has a very beneficial effect on sound, which is logical. But because of the bad crossover it was necessary to protect them somehow.

The other is a stupid thing is rubber ring they put in to control resonance membrane. I understand the engineering (since I am an aircraft engineer) approach to having a goal and now looking for a way to reach it, but you have to be aware that it is all a matter of compromise. Now, either they were aware that the sound would be compromised or they relied too heavily on measurements, and they didn't care much for the sound. Again on the other hand if they didn't do it I wouldn't be able to use the 6db / Oct switch with AL drivers.

I still enjoy these speakers, but I know it can do better, and that's what annoys me. The sound of the piano is slightly blurred because of the rubber that exists between the voice coil and the membrane. The voice coil and membrane must be firmly attached in order for even the smallest vibrations to be transferred to the diaphragm and converted into an acoustic signal.

I hope Dr. Jack Oclee-Brown is aware of this problem.

This phenomenon is also present in the R series of drivers, and is also present in bass drivers. It measures ok or doesn't sound good. Goes deep but sounds muffled. ]
 
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Shoba

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Very interestingly, I have a feeling that this is exactly what Amirm noticed on the Kef R3.
A perfect speaker for all parameters, but ...
 

tecnogadget

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That On-Axis and in-room from Jokerbre look impressive and shows how much you can get with that driver plus optimized crossover and cabinet. I like the bracing inspired by the LS50 and R line "constrained layer damping" style.

Really nice info. But concerning the statement about "rubber ring" being a flaw while KEF pretty much declares it a feature... Not only they have fitted this technology in the Q series UniQ driver, but they also use it for the R series, Blade, and The Reference (the highly praised speaker that excels in pretty much every objective/subjective review). Of course that all speaker design decisions involve making compromises, but still I doubt it is a "stupid thing" if they are using it on a $20,000/pair speaker.

From Q Series:
"Additionally, the problem of the high-frequency band resonance of the metal cone has also been overcome by the development of a new KEF technology called Cone Breakup Control."


From R Series 2018:
"Midrange Cone and surround: The cone is formed from a magnesium/aluminum alloy. Like the front skin of the bass driver, it serves to provide the necessary stiffness to give pure pistonic motion over the driver’s working range. The stiffness is increased by the radial embossing in the cone profile, but it is prone to high-Q breakup in the frequency range covered by the tweeter. "

The KEF Blade uses a nodal drive to tame these resonances. But that technique, when applied to a Uni-Q array, cannot use an intermediate cone and instead requires an expensive large diameter voice coil which was not appropriate to the R Series.
Instead, there is a lossy interface where the voice coil joins the cone. This interface serves to decouple the drive at high frequencies. The high-Q resonances are tamed to the extent that they may be properly attenuated by the crossover and not break through the tweeter output."

1587981446625.png

From The Reference:
"Aluminium is a very good choice of material for a loudspeaker diaphragm as it is both stiff and light and also easy to form into a complex shape. The stiffness and low mass mean that the cone operates as a rigidly body over the entire midrange region.

The issue with metal diaphragms is that when they do enter breakup, as they have little internal damping, very large irregularities in the response occur These can be easily 15dB or more in magnitude. This is large enough to be a problem even if a breakup occurs well above the crossover frequency. It is possible to add damping material directly to the cone to control these resonances, however; this is not a good solution as this direct damping application is very heavy and this results in a driver with low sensitivity.
KEF uses a unique technology called cone neck control to avoid the traditional breakup problems of metal cone drivers. With cone neck control the cone is not rigidly connected to the voice coil of the driven A resilient high damping link is used to connect the two parts together. This link is carefully designed and fine-tuned with the help of computer modeling so that within the band of the driver the force from the voice coil is fully transferred to the cone. Above crossover; however; the resilient link begins to flex and to damp the cone motion. The effect on the driver response is quite dramatic. The breakup peak from the driver is reduced by around 15dB and the driver response considerably smoother The penalty is a small mass increase in the moving parts, albeit much less than using a direct damping approach."

1587981882258.png

1587981930324.png


Maybe @jackocleebrown could give us an insight into this...

Then there is the ferrofluid issue that is well known for old/legacy speakers in which it dries out. This happened a lot with the T33 tweeter. But I've never heard any issue on ferrofluids with contemporary Q, R, or Reference series...I must admit I'm clueless as if ferrofluid is inherently used in every metal dome tweeter as a standard practice. Kef never states it in their spec sheets of whitepapers. And latest UniQ uses a vented tweeter configuration (not sure if it's related or not).

All those statements IMHO should be backed up with measurements (Cone Breakup Control & Ferrofluid) as like Erin hardisj did with this driver.

Very interestingly, I have a feeling that this is exactly what Amirm noticed on the Kef R3.
A perfect speaker for all parameters, but ...
Still, nothing wrong showed up in his measurements with regards to that matter, and after he figured out his room mode affected bass reproduction, he dialed an EQ filter and changed his subjective impressions for the better with no complaints.
 
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Ilkless

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https://www.diyaudio.com/forums/multi-way/352846-justice-kef-q100-2.html#post6165759

[ In my opinion, this speaker sounds better than the LS50. But...

As with the LS50 as well as the R300 also with this speaker, I have problems with two things. The first is the ferrofluid in the tweeter. The tweeter sound is great but it can be better. I have repeatedly found that removing ferrofluids from the tweeter has a very beneficial effect on sound, which is logical. But because of the bad crossover it was necessary to protect them somehow.

The other is a stupid thing is rubber ring they put in to control resonance membrane. I understand the engineering (since I am an aircraft engineer) approach to having a goal and now looking for a way to reach it, but you have to be aware that it is all a matter of compromise. Now, either they were aware that the sound would be compromised or they relied too heavily on measurements, and they didn't care much for the sound. Again on the other hand if they didn't do it I wouldn't be able to use the 6db / Oct switch with AL drivers.

I still enjoy these speakers, but I know it can do better, and that's what annoys me. The sound of the piano is slightly blurred because of the rubber that exists between the voice coil and the membrane. The voice coil and membrane must be firmly attached in order for even the smallest vibrations to be transferred to the diaphragm and converted into an acoustic signal.

I hope Dr. Jack Oclee-Brown is aware of this problem.

This phenomenon is also present in the R series of drivers, and is also present in bass drivers. It measures ok or doesn't sound good. Goes deep but sounds muffled. ]
This is a classic example of intuition and folk theory masquerading as legitimate alternatives to empirical evidence.
 

maty

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Just because I reproduce his comments does not mean I share them in full. For example, he complains about how the piano sounds but in mine (modified) it sounds great.

The woofer breakdown problem can be solved with a slightly more complex filter.

What is a shame are the thin walls of MDF. Or material damping is addeed by us or we build new boxes. I opted for the former and the improvement was very substantial. Now they weigh more than the LS50. I said, the driver is very good, they saved the rest. Presumably the Q150 driver will be better, but they saved on the driver skeleton and in the inductor (woofer filter).
 

tecnogadget

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Just because I reproduce his comments does not mean I share them in full. For example, he complains about how the piano sounds but in mine (modified) it sounds great.

The woofer breakdown problem can be solved with a slightly more complex filter.

What is a shame are the thin walls of MDF. Or material damping is addeed by us or we build new boxes. I opted for the former and the improvement was very substantial. Now they weigh more than the LS50. I said, the driver is very good, they saved the rest. Presumably the Q150 driver will be better, but they saved on the driver skeleton and in the inductor (woofer filter).
That's exactly how I interpreted your post and the reason I did not quote you. I would have quoted Jokerbre if he was a member, he is always welcome here.

And I agree with you about those thin walls. I remember how I was interested in that Q generation around 2014 when I was looking for a center channel upgrade. I first dreamed about the Q200C but the lack of information around that time (lesser measurements than 2020), my lack of experience and having passive radiators made me doubt about it being the "perfect voices" center overkill I was dreaming of. In the end, I end up making a great deal for an R600c (yeah gigantic monster, I had to reinforce the previous stand to prevent bending haha).

I consider myself a Kef fan, but I admit that I consider the previous Q series as their budget line (I'm not saying cheap). They tried to squeeze too many great technologies from their big brothers UniQ drivers at the expense of compromising cabinet and "system as a whole".
This still a very good speaker, but not so great in stock form. It's a raw diamond by means of a great UniQ driver.

I wish the Q150 or Q350 were measured in the near future to find out if the line has been optimized :cool: . I was shocked when I saw they introduced the same rib stamp on the drivers as the big brothers, I thought they would always reserve that to premium. I really like how they borrow tech from higher series into all of the products.
 
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@amirm THANK YOU! Finally proper, real reviews. I just registered for the forum as I found the Holy Grail -- spinoramas :D

I am still new to digesting this info and would like to ask one clarification question. Assuming the Q300s are similar to the Q100, when you guys say that they perform better at 20 degrees - what does that mean? Does 20 degrees mean no toe in at all? Basically have the speaker pointing straight towards the back wall?

@maty thank you for these pic from the manual; I never read it. After years of playing around, I discovered for myself that the speakers are better integrated with subs when plugged. And now I see it is in the manual :eek:

But going back to my question, the manual suggests a toe in of ... 30 degrees?


 
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tecnogadget

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@_Bass Welcome to ASR !! Good to know you are enjoying your KEF’s.

As for the subwoofer that is a standard recomendation for any kind of Bookshelf, and even for Floorstanders.

Those graphics from the manual are “general guides”. They are not actually stating to place it one way or another, instead they give you the choice of no toe-in at all or to try different degrees of toe-in. That will highly depend on your room dimensions, speaker placement, and personal taste.
 

maty

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@amirm THANK YOU! Finally proper, real reviews. I just registered for the forum as I found the Holy Grail -- spinoramas :D

I am still new to digesting this info and would like to ask one clarification question. Assuming the Q300s are similar to the Q100, when you guys say that they perform better at 20 degrees - what does that mean? Does 20 degrees mean no toe in at all? Basically have the speaker pointing straight towards the back wall?

@maty thank you for these pic from the manual; I never read it. After years of playing around, I discovered for myself that the speakers are better integrated with subs when plugged. And now I see it is in the manual :eek:

But going back to my question, the manual suggests a toe in of ... 30 degrees?
If they sound good to you now, if you follow my recommendations, spending the minimum, you would get an even better sound.

The only thing worthwhile is the driver, which is excellent. With a few tweaks to the frequency curve it improves clearly, and without spending a penny.
The box needs mass + cushioning. Mine now weigh more than the KEF LS50.

And then there is the tuning of the simple crossover or a new one.

If you then add the optimization of the W10 for multimedia ... you are amazed at the sound.

All of the above is valid or worthwhile if you listen to excellent recordings and with great dynamic range.
 
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I do not think I am skilled enough to do mods :) So I can only do positioning, alignment with two subs, measurements, EQ (using Audissey XT32 with my AVR btw). Also to be clear, I have the Q300 which measure a bit different than the Q100.

I did REW measurements from my MLP 8 ft away with and without toe in and here are my results. Which is technically the better response? To me it seems like I need to toe them in.
Physchoacoustic Smoothing.png
1 12 Smoothing.png
 
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maty

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Impressive how they play an orchestral mass (1961 analog master -> 2014 remastered), just now:

Ernest Ansermet, L'Orchestre De La Suisse Romande - Classical Symphony / March And Scherzo / Kamarinskaïa Fantasy / A Life For The Czar / In The Steppes Of Central Asia [Prokofiev / Glinka / Borodin] (1961), Vinyl, Speakers Corner Records 2014, Germany
https://www.diyaudio.com/forums/music/6958-playing-listening-post6230501.html

https://www.discogs.com/Prokofiev-G...e-Classical-Symphony-March-An/release/7814217
https://www.speakerscornerrecords.com/products/details/2292/prokofiev-classical-symphony

Without subwoofer and near field.
 

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Just read this entire thread, much of the science goes above my head tbh, I understand basic FR graphs though, mainly because I'm a headphone junky, that being said, I personally can only judge a speaker or headphones by how it sounds, you look at the FR graph of something like a K712 Pro and it looks pretty messed up but to my ears it sounds wonderful! Of course, science plays its part but the result of that science is the sound, and that's the most important aspect for me, the final result. I love the Q100's, it's genuinely one of my favourite speakers under $500, I have had Wharfedales, Mordaunt Shorts, Good old British Rogers (they were nice!), B&W's (Still have some old DM602's!), Monitor Audio, and many more, the Q100's still give me a smile, they are warm but the detail is still there.

I have two sets of the Q100's, one set I use for nearfield, of all the speakers I tried the Q100's was one of the rare speakers that still gave me some a sense of imaging and soundstage while not being in the prime listening position, I agree that the cabinets let the drivers down unfortunately but then these were thier entry level speakers so I guess they had to cut corners somewhere, but I think the driver itself is very good.

Regarding the distortion you say you heard, I used to get some distortion that was particularly apparent on piano tones and higher pitched female vocals, I wasn't sure if my speaker was faulty, I grabbed a second set of Q100's that I acquired second-hand and they did not have the problem at all, they also sounded smoother up top, apparently they was run in quite hard, so I proceeded to try running in my then relatively new set of q100's and it actually cured the problem after a good month, my problem is I very rarely play my speakers very loud and it can take quite a while to run them in but it definitely made a difference on these.

Not sure how you guys will take this post as it's pretty subjective and I don't really have any numbers to throw down but just thought I'd chime in as these area fav of mine.
 
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maty

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You know, you can improve a lot the sound of the Q100 without to spend a lot of money. First with soft (Rephase), then inside (walls) and finally the crossover. Step by step.
 

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