Tought on this q concerto mod ?

[Terrycloth]

Hi everyone,


I recently stumbled across an interesting series of internal tweaks made by "Tweakradje" to the new KEF Q Concerto Meta. His mod focuses on refined crossover parts and improved cabinet damping.

tweakradje - KEF Q Concerto meta

The result To be able to hear space, placement, delays and clarity as never before. Singers in your room, hearing their vocal cords vibrate, hammer strikes of the piano, etc. Addictive. Sometimes even scary with some sounds because they are so realistic you think someone makes them in the room

sites.google.com

Summary of the changes:

• Replaced the original 3.9 Ω inline resistor in the tweeter’s path with a 2.7 Ω Jantzen Superes resistor (~+1.7 dB gain above 2.9 kHz)
• Swapped the stock 39 µF electrolytic midcap for a 39 µF Jantzen Cross-Cap
• Added an upgraded 1.2 mH Jantzen air-core coil in the midrange path (added in April 2025)
• Increased internal Sonofil damping—two rolls rearranged and a portion added into the mid‑box

These mods cost about €70 + some effort, with no driver substitutions or DSP involved—just component and damping improvement. The result, according to Tweakradje and one listener in Barcelona, was a more open, detailed sound “lifting the veil,” with enhanced clarity and staging .

I am actually making a home theater, i have 2x q150 for rear, 4x kef ci13ER for atmos height, and two kube 12b.
I have also ls50 wireless 2 that i love but planning to sell them because they not integrate well in a AVR system.
Room is 4x4 meter.
i was struggling between getting 3 LS50 meta to keep the same sound i was wondering about getting Q concerto META with Q6 META, but the sound with the q concerto meta feel much darker , and soundstage less wider that the ls50.

Do you think these king of mod can improve the linstening to especially in the treble region or i just have to stick with ls50? Especially in my room size.
Use will be 50/50 music/movie.

Best regards.

 

[voodooless]

The swapped coil and cap will almost certainly not do anything at all. The resistor will certainly have an effect, but:

These mods cost about €70 + some effort, with no driver substitutions or DSP involved

You’re going to use these in a home theater, so EQ is almost inevitable. You’ll get the “upgrade” for free.

Sonofil: sure, that may be effective in damping some more resonances, but I think the speaker is already quite good as-is.

As for vails lifted… probably a lot of expectation bias.

 

[raindance]

EQ = much less effort.

 

[Francis Vaughan]

"Upgrades" like this are, at best, always a total waste of time and money.
They might make sense if there is a clear problem in the design, whereby changing things might help. KEF are not fools, so we can reasonably discount that.
The resistor value change will ensure that the speaker actually sounds subtly different. It will become brighter. In the modern world messing with crossover values to address tonal balance is just plain wrong. Messing with the internal stuffing of the mid box is not something done lightly. It can easily change the sound by wrecking the frequency response. Additional stuffing does not automatically mean better damping. Too much stuffing and damping efficiency falls. Again, KEF are not fools, and the speaker, as manufactured, is excellent. A wobbly frequency response is the classic way you get loudspeakers that suddenly sound special on certain instruments. Nobody mentions those instruments that now sound wrong. This is just stepping back a couple of decades into the dark ages of audiofoolery.

Your room will dominate everything. How the speaker's directivity fits with your room should be a better guide. These are all excellent loudspeakers, so there should be no issue making them work. EQ is your next port of call. With care.

 

[Chagall]

If you are getting Q6 meta and feel like Concerto is dark, why not just get 2 more Q6 metas? Use 3 of them for LCR.

Not seen any Q6 measurements yet, but being a sealed speaker they will have less bass (that doesn't matter because you have 2 subs), can be placed closer to the wall and might be brighter then Concerto IMO.

It doesn't make sense to buy new speakers if you don't like the sound just to then "fix" them.

 

[tweakradje]

Found this thread about the Concerto Mod I did. I agree with most posters about the effort it takes to do the mods and if it is worth it.
I totally disagree with the comments of the lack of improvement of the upgrade (placebo/snakeoil). It is more of an opinion I guess than based on real life experience.
My opinion: Quality of Crossover Parts do matter if applied properly
Pitty I cannot give you a real life demo here. It might raise some eyebrows. We're all looking for that musical emotion that gives us goosebumps. Stay sound.

 

[kyuu]

Found this thread about the Concerto Mod I did. I agree with most posters about the effort it takes to do the mods and if it is worth it.
I totally disagree with the comments of the lack of improvement of the upgrade (placebo/snakeoil). It is more of an opinion I guess than based on real life experience.
My opinion: Quality of Crossover Parts do matter if applied properly
Pitty I cannot give you a real life demo here. It might raise some eyebrows. We're all looking for that musical emotion that gives us goosebumps. Stay sound.

Please show us measurements demonstrating the improvements from the crossover parts swap. Sighted listening tests are useless, so please don't bother telling us to do one or relating yours or someone else's subjective impressions unless the listening test was blinded. Thanks.

 

[Svend P]

Quality of Crossover Parts do matter if applied properly

You won't find support for that notion on ASR. This thread gives some more insigt into why that is.

Crossover Component Recommendations

Hi, I'm diving into the world of DIY speakers and would appreciate some guidance regarding crossover components. I've worked with electronic components in the past (industrial level) and am comfortable with the how and why, but audio seems a minefield of snake oil and profligacy, and I find...

www.audiosciencereview.com

 

[tweakradje]

Thanks for the clear feedback. Think you have to agree that there are some stereo sound reproduction qualities that cannot be measured properly yet.
How do you measure/plot data/quantize of things like center focus, image depth, instrument separation, clarity to name a few. You cannot say they don't exist.
I'm just a tweaking paying private customer with a few years of experience and created the page to share my experience, because I think/hope it can help others too. (and it already did) I'm not forcing anyone to do anything. And I owe nobody anything (except my wife sometimes).
In the mean time much love and enjoy your music

 

[MAB]

@RickS
New member appears to need a vendor tag.

Found this thread about the Concerto Mod I did. I agree with most posters about the effort it takes to do the mods and if it is worth it.
I totally disagree with the comments of the lack of improvement of the upgrade (placebo/snakeoil). It is more of an opinion I guess than based on real life experience.
My opinion: Quality of Crossover Parts do matter if applied properly
Pitty I cannot give you a real life demo here. It might raise some eyebrows. We're all looking for that musical emotion that gives us goosebumps. Stay sound.

Welcome to ASR. Some of us members design and build speakers, and measure them, and listen to music on them too. You may be surprised at what we have heard.

 

[MAB]

@ctrl has done a nice series on the actual changes in sound due to crossover components

Capacitor upgrade in crossover - Is it audible?

As the topics "capacitor upgrade" and therefore "capacitor sound" is very controversial, the test method and its results are explained in detail. This cannot be dealt with in one minute. Sorry for this and I hope your attention span is still sufficient to read through a long text - whereby the...

www.audiosciencereview.com

Replace resistor by low-inductance resistor - Is it audible?

Since it is often claimed here in the forum that replacing cheap sand-cast resistors with low-inductance resistors would lead to clearly audible improvements, and since it's no use pointing out that the sound change (unless it's completely imagined) is very likely due to slight deviations in the...

www.audiosciencereview.com

Different Binding Posts - is it audible?

The influence of BP on the sound of loudspeakers has often been controversially discussed. It even goes so far that individual voices describe the influence of binding posts as immense and recommend only very high-quality BPs - That made me curious. The full mini series: Capacitor...

www.audiosciencereview.com

Audible difference in high-end capacitors? - ABX samples

As announced long ago the last part on the subject of audibility of capacitor upgrade in crossovers. The comparison ranges from a very cheap, decades-old film capacitor to an expensive high-end capacitor. As promised, this time there are short audio samples of each capacitor (in a simple...

www.audiosciencereview.com

It's nice to know that the laws of physics still apply to components, even when used in a speaker crossover.
The changed resistor in this crossover tweak will indeed change the sound, not because of the brand or model of resistor, but because of the change in the value of the resistance.
The new inductor may have a small change in the sound if it has different DCR. Probably not though.
People have been overstuffing cabinets as a tweak for years, it may slightly change the bass but not nearly as much as moving the speaker a few inches in the room.

 

[tweakradje]

@RickS
New member appears to need a vendor tag.


Welcome to ASR. Some of us members design and build speakers, and measure them, and listen to music on them too. You may be surprised at what we have heard.

Haha thanks. I'm 60 now and you may be surprised what I have heard (Live and Hifi). Have build many designs too. I know what Amir does. I know what Danny Richie does. Still learning. Cherry picking. But this is getting off topic now... Anyway I think there is nothing more to add to the OP. Bye.

 

[RexrothPigeon]

Haha thanks. I'm 60 now and you may be surprised what I have heard (Live and Hifi). Have build many designs too. I know what Amir does. I know what Danny Richie does. Still learning. Cherry picking. But this is getting off topic now... Anyway I think there is nothing more to add to the OP. Bye.

If you're "still learning," you'll read the @ctrl threads linked above by @MAB
If you don't, it's safe to say that you are too hooked on snake oil to be open to learning

 

[tweakradje]

Too many frustrated people here telling other what to do. I'm out.

 

[DVDdoug]

Think you have to agree that there are some stereo sound reproduction qualities that cannot be measured properly yet.

If you have the proper equipment, measurements are BETTER than human hearing. Understanding Speaker Measurements (video).

Any CHANGES from modifications can "easily" be measured, especially electrical/crossover mods that don't affect directivity. If you change a tweeter or waveguide or make major physical/acoustic changes you need to measure on-axis and off-axis response/directivity and that is more complicated.

Uncontrolled subjective listening tests are useless. Especially if you modify both speakers and try to remember what they it sounded like before. Or if you are reading what someone else is perceiving, or think they are perceiving. When you make a mod you are likely to be biased and hear an "improvement".

You COULD modify one speaker and do a Controlled Audio Blind Listening Test. That makes A/B comparisons more valid. But if you made a mod that obviously boost the highs making the test blind isn't really "blind" because if you hear a difference in highs you can always identify A or B.

If you are not doing measurements you'd need to do blind listening tests with an "unbiased" listening panel. Even though these listeners might be able to easily hear the difference and always identify A or B, if they don't anything about the speakers or which one has been modified it can be a valid listening test.

How do you measure/plot data/quantize of things like center focus, image depth, instrument separation, clarity to name a few. You cannot say they don't exist.

Right! You can't measure perceptions and impressions. Your brain is interpreting what you're hearing, and although you can measure EVERYTHING that affects those perceptions you can't necessarily CORRELATE the measurements with what your brain is telling you.

Room acoustics are also involved, and if you move your seating position the sound will change. Floyd Toole says:

...to claim that a smoothed steady-state room curve derived from an omnidirectional microphone is an adequate substitute for the timbral and spatial perceptions of two ears and a brain is absurd.

 

[Ktacos]

How do you measure/plot data/quantize of things like center focus, image depth, instrument separation, clarity to name a few.

Typically those aspects are affected by dispersion, cabinet diffraction, room reflections, which can all be put into numbers.

 

[RexrothPigeon]

Too many frustrated people here telling other what to do. I'm out.

Yes, probably for the best. Staying here and learning might imperil your livelihood (selling snake oil ineffectual "tweaks" for €40 a pop).

 

[kyuu]

If you think there's something there that isn't captured in the measurements, that's fine. Show it's really there with a properly controlled double-blind listening test before you insist we go chasing fairy tales.

 

[Ralph_Cramden]

OP: Any idiot can create a web page and claim his tweak will work wonders. KEF has been in business for decades, designing, building and selling speakers that measure consistently well. Why would you listen to a random idiot vs KEF?

 

[terryforsythe]

The swapped coil and cap will almost certainly not do anything at all. The resistor will certainly have an effect

I agree with your sentiment regarding the capacitor and resistor. I disagree, however, with the inductor. Air core inductors eliminate core hysterises and eddy current losses, which are not insignificant when operating in the upper midrange frequencies. The issue, however, is ensuring that heavy enough gauge magnet wire is used for the air core inductor so as not to increase the DCR. The other issue is whether the prototypes were tested and evaluated with the specific inductor design used in the final production crossovers. Oftentimes that is not the case, but KEF seems to be more thorough in their engineering than other speaker companies I have seen, so perhaps they were. If so, the design may be optimized for the expected core losses.