Embedded Files
KEF Q Concerto Meta
Uni-Q-driver-array: HF: 19 mm vented aluminium dome MAT
MF: 100 mm aluminium cone
Bass-unit: LF: 165 mm hybride paper/aluminium cone
Crossover frequency: 430 Hz / 2.9 kHz
Amplifier: Onkyo R-N855 (2x70W at 4 Ohm Class D, direct mode, very revealing amp)
Tried the Eversolo Play as amplifier but its too tame.
Here you will find pictures of the inside of the cabinet and the crossover.
Recordings wav/mp3 (straight from Tascam DR-05X sdcard, use good headphones!!!)
Audio recording after mod (16bit 44.1 Khz WAV)
Another test recording (16bit 44.1 Khz WAV performer Vitaly Makukin)
And another pretty good recording (MarkusPhilippe - Sensuelle)
After last (coil) mod. Project closed now.
Very raw Recording and for soundstage Rule Brittania
Random radio streams recording of guitar and piano
Recording 9 (16bit 44.1 Khz WAV)
Recording 10 (16bit 44.1 Khz WAV)
Test hires audio AAC file for download only for educational purposes (Driss El Maloumi - Awzan).
16 feb 2025: after trying some resistor values I settled for 2.7 Ohm for the highs (original 3.9 Ohm)
06 apr 2025: Mods on mid coil see bottom of page. Project closed.
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. If you cannot do these mods I think there are better speakers for 1200 euro (like the Revel M16)
Owner Feedback on Mods (love to hear your feedback too)
Ruben from Barcelona (march 2025): ""The sound improvement is mind-blowing. Before, I thought terms like "airy," "spacious," or "holographic" were just audiophile fluff. But now? I get it. My speakers sound like they’ve doubled in value. Genuinely. It’s separating sounds in space in a way I’ve never experienced before. It’s wild. It’s eye-opening.
Thanks again for your support and knowledge — it made the whole process super enjoyable!"
David from Australia (june 2025): "One obvious result is the soundstage is more grander and central - properly setting up the speakers and tilting them upwards a touch elevates this further. Since the mod vocals are center, presence almost feels like a small concert in some songs, instruments are either at speakers or in-between and drums are usually 'behind' the vocals, if slightly right or left."
Out of the box and reason for mod
Upgraded from the original ELAC Debut 5 and KEF LS50 Meta to the KEF Q Concerto Meta.
The KEF Q Concerto Meta is a big bookshelf 3-way speaker. I expected a lot of it on bass, soundstage and clarity. Coming from the LS50 Meta it didn't have the metallic sound signature and is VERY good at lower volume. I was looking for this.
After a week or so I wanted to go back to the LS50 Meta. Why? Concerto had lack of mid clarity and highs. Also missed the addictive grand soundstage of the LS50 Meta, which initially was less there in the Concerto.
(I still recommend the LS50 Meta for its sound stage and details if you can live with the metallic sound signature!)
As tweakers do, I opened the cabinet of the Q Concerto Meta to see what was inside. Could it be improved with filter parts quality? Can I keep the good properties and improve others?
Erin's Youtube video gave a perfect measurement and some clues. Lower output on the upper bass and highs.
The crossover is pretty simple (but cheap), indicating the drivers are well-behaving performers.
Crossover place for better resistor
Crossover underside
Stamped frame long throw Woofer, well vented
The original crossover
Rule of thumb: parts in series matter most (path terminal to driver connector), higher frequencies affected more by inferior parts
Shopping list:
002-0181: 2.7 Ohm 10w Jantzen Superes
001-0280: 39 uF Jantzen Cross Cap
000-1467: 1.2 mH Jantzen air coil (1mm)
The mod (step 1)
Why? I suspect KEF deliberate "crippled" the Q Concerto to avoid conflict with the R3 Meta. Mind you the R3 Meta is twice the price!
To raise the tweeter level by about +2 dB, add more clarity to the midrange driver, and flatten the bass response.
Note: I use them with grilles (cat!)
Damping material consists original of 3 rolled up sheets of Sonofil.
The first roll I left rolled up in the bottom back, up to the connectors cup.
The second sheet is now folded once at the back panel, from the bass reflex to the connectors cup, against the rolled up sheet in the bottom back.
The third sheet is now folded once at the bottom of the cabinet, over the crossover and up to the connectors cup.
(see sketch below)The cheap 39 uF bipolar electrolitic capacitor from the mids has been replaced with a Jantzen Cross-Cap of 39 uF (needed 2 extra drill holes on the board)
The 3.9 Ohm inline resistor in the high freq path has been replaced with highres 2.7 Ohm, adding 1.7 dB from 2.9 KHz up
Filled the mid driver cabinet section with sonofil, halved the damping foam of the bottom piece (it was too much sticking out into the driver)
Since my speakers are closer than 1 feet to the back wall I need to use the outer ring of the bass foam plug in the reflex port. Else 40 Hz is too much.
Note: upper beauty ring is magnetic, other one uses pins. Use a sharpened corner of a credit card to remove the rings without damage!!!
Note2: the plastic crossover stands are best removed from the cabinet wood with long thin pliers to keep them intact
Note3: use a flat hobby knife or similar to remove and clean the white silicone glue that holds the part to the pcb
Crossover modified (green resistor and big capacitor)
Crossover solder points and 2 new drill holes for capacitor
Two of three sheets Sonofil reapplied to bottom and back
No plans to repace laminated iron core with air core inductors on the mids soon. But I will do it one day as it makes a difference on mids.
Cost of the Mod: about 40 euro and some sweat not to damage anything
The mod (step 2)
Edit april 2025: The last step, replacing the 1.2mH (0.55Ohm) mid coil. A video from Barcelona easily convinced me. So today task done: drilling, hot gluing and soldering.
Did it make the expected difference? Oh yeah, even more. It lifted the veil. Speaker sounds even more open, detailed and lively. Cost: another 30 euro
Drill holes for the new Coil
Original
Mid tone chamber mod (step 3 optional)
The mid chamber on the left is how it original looks (better remove drivers with metal plate!). There are four foam strips on the sides, nothing on the back plane.
It needs more damping since there is some ringing visible in the waterfall measurement.
I took the bottom foam strip out and halved the height of it and put that back at the bottom. Cut 4 (4x4x4 cm) squares from the Sonofil and put in each corner, one corner under the back foam. Then cut a little oversize square piece from the white Sonofil blanket (not thicker than 2 cm) from the main cabinet and put it into this mid chamber and the corners, over the 4 corner pieces.. The driver will keep everything in place.
Note: the top and bottom foam strips are the same. If you want to restore full height bottom strip move the top to the bottom and put the two halves at the top.
One of the iterations
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