The traces in figs.1 and 2 have a small wrinkle between 600 and 700Hz, suggesting the presence of a cabinet resonance in that region. However, when I investigated the vibrational behavior of the enclosure panels with an accelerometer, there was nothing untoward between 600 and 700Hz. However, there was a fairly strong mode at 309Hz on all surfaces (fig.3), and a slightly less strong one at 504Hz.
(https://www.stereophile.com/images/318K350fig3.jpg)
Fig.3 KEF Q350, cumulative spectral-decay plot calculated from output of accelerometer fastened to center of sidewall (MLS driving voltage to speaker, 7.55V; measurement bandwidth, 2kHz).
The small blip at 39kHz in the magnitude trace in fig.1 indicates that the tweeter's fundamental dome resonance lies at this very high frequency, but the traces in this graph are otherwise free from the small lower-frequency discontinuities that would suggest the presence of cabinet resonances of some kind. Cumulative spectral-decay plots of the cabinet walls' vibrational behavior, calculated from the output of a plastic-tape accelerometer, didn't uncover any midrange resonances on any of the surfaces, though the sidewalls flexed a little at the frequency of the port tuning frequency (fig.2).
(https://www.stereophile.com/images/1212KEF50fig2.jpg)
Fig.2 KEF LS50, cumulative spectral-decay plot calculated from output of accelerometer fastened to center of side panel (MLS driving voltage to speaker, 7.55V; measurement bandwidth, 2kHz).
Dan S. Higgins
The Q350's Take Time to Break In
I've been listening to the Q350's for about five weeks and the woofers are still not broken in; that warm speaker feel and sound hasn't come to fruition yet. I'm confident with more time they'll loosen up, and warm with time.
I use an iPad Mini 4 as the sound source and have found the "rock" setting in the equalizer sounds best overall. The integrated amp I use is the Yamaha AS-801 and I need to turn the bass knob to about "two o'clock" to get the warmth I like to hear. The only track I've seen to actually work and move the woofers is Rocket Empire's 'Cruising the Galaxy', loud.
YAMAHA A-S801
Rated power (1% THD + N, 1 kHz) [W] 8 Ω, 2x 130
Rated power (1% THD + N, 1 kHz) [W] 4 Ω, 2x 132
Sensitivity (for maximum power) [V] 1x 0.22
Signal / noise ratio (A-weighted filter, with reference to 1W) [dB] 83
Dynamics [dB] 104
Damping factor (relative to 4 Ω) 94
This graph shows that the SR4500's left channel, from CD input to speaker output with two channels driving 8-ohm loads, reaches 0.1% distortion at 100.4 watts and 1% distortion at 114.6 watts. Into 4 ohms, the amplifier reaches 0.1% distortion at 128.2 watts and 1% distortion at 158.8 watts.
Response from the multichannel input to the speaker output measures –0.43 dB at 10 Hz, –0.13 dB at 20 Hz, –0.11 dB at 20 kHz, and –0.67 dB at 50 kHz. THD+N from the amplifier was less than 0.015% at 1 kHz when driving 2.83 volts into an 8-ohm load. Crosstalk at 1 kHz driving 2.83 volts into an 8-ohm load was –79.69 dB left to right and –80.28 dB right to left. The signal-to-noise ratio with 2.83 volts driving an 8-ohm load from 10 Hz to 24 kHz with "A" weighting was –100.92 dBrA.
Wonderful Speakers
By Mike Anderson December 22, 2018
These speakers sound fantastic, look wonderful, and shine at reproducing guitar. The bass is significantly more than I was expecting and on par, but much cleaner, than my old Spica TC-50's. As stated by everyone else the imaging is ridiculously good and really fun to play with. I tried out one of the main competitors (rhymes with "dorfdale") and found these more suited to my musical taste which is along the lines of Jack Johnson, Rush, and movies. Of course considered the UB5 [maty: ELAC] but settled on these. Only thing to note is that the tweeters took about an hour to warm up so dont freak out when you first set them up.
frequency response
(±3dB) Measured at 85dB/1m
45Hz – 28kHz (More bass extension)
50Hz – 28kHz (Standard)
61Hz – 28kHz (Less bass extension)
Depending on speaker settings <- DSP
WEIGHT
Left Speaker 10.0kg (22.0lbs.)
Right Speaker 10.2kg (22.5lbs.)
...Sound quality: Wow. It's really hard to describe how these sound because it's almost like the sound isn't coming from the speakers at all. What I can detail is how clear and crisp everything is. The highs are crisp and crystal clear. The mids are clear and warm. Then there's the bass. Do not believe in the frequency range numbers. These definitely go down beyond the claimed 51Hz. I was worried about having to get a subwoofer, coming from RP-500m's, but these produce an astonishing amount of bass for the size. Provided in the box are two bass port plugs with 2 stages: both foam pieces together or you can remove the inner foam piece for just a foam ring. My advice: put them in with just the outer foam because it tightens up the bass and makes it less boomy. All in all, these sound great. I like electronic music mostly and these are perfect for EDM or house music. Deadmau5 sounds amazing on these. Likewise, these will sound great with pretty much any genre of music.
I'm powering them with a Nobsound TPA3116100Wmini amplifier and it's plenty of power. I did recently purchase an Audioengine N22 amplifier and while it sounded great with the KEFS, it unfortunately had unbalanced channels. So I'm sticking with the Nobsound for now. I'm sure these would sound much better with a high end amplifier, but it shows how forgiving these are of the power source.
In conclusion, these are great for near field listening: punchy bass, warm mids, and crystal clear highs. These definitely need to be broken in because they will sound harsh during the first couple of hours. After that, they become mellow and warm sounding. It's easy to listen to and pretty to look at. Can't wait to see what KEF does in the future!
by Shane from Clay, MI on 12/27/2018
These are excellent. After a Christmas shoot out with another pair of speakers that we're getting rave reviews, these beat them out immediately. They're going in my office with my Elac Unifi UB5's. That's who they compete with. Bass great. Treble is a little crisper than the Elacs which is nice. It's not overwhelming though. Soundstage is apparent right out of the box. Digital Trends got the analogy correct. If the Elac Unifi UB5 is a Chardonnay, then the KEF q150 is a smoky Pinot Noir. Right on. The Elac mids stand out a little more. The KEF's are the more laid back Brit sound. I absolutely love them. Highly recommended. Powered by an old Onkyo 809 receiver and Oppo bdp 93
Pros: Great bass. Crisp highs but not etchy at all..just enough. Great soundstage
Cons: Not as much attack as say a horn speaker but it's really not a con. It's preference. I could listen to these for hours without fatigue.
I get very loud deep bass, they sound quite bloated and they lack definition / punchiness. I don't feel the bass when in certain sound I know I should feel it. They're currently powered by a Marantz M-CR511 (40w in 8ohms), could the problem be there?
To be more specific, they're in a 20 square meters room, both on 60mm stands, 30cm from the wall...
To be more specific, they're in a 20 square meters room, both on 60mm stands, 30cm from the wall...
Ok so I spent hours listening to different musics that I know and placing the speakers at different positions in my room. I finally found something that sounded good! Without any ajustement on my receiver I finally was able to detach the voice of Jack Johnson from the bass in "Middle Man".
The only problem is that it was almost in the middle of my room and facing a corridor so I could not let them there but what's sound the closest at the moment is when I place them in their original place and change the output frequency characteristics to cut the low frequencies of 60 Hz or under by –12dB/oct.
Still not perfect I guess because I feel like I'm loosing some bass...but I'll try to buy another amp later if I can to see if it improves. Something like a Marantz PM6006, I heard that it might have better control than my AVR. I won't be able to try the Q350 as it's a bit over my budget at the moment and I thought that for the size of my listening room the Q150 would suffice.
Hey guys,
This is a response to the feedback I had on the measurements I made. I see now that they can be very misleading if you do not pay attention to the scale. So here are the new measurements (that I just made) of my KEF Q150. I used a 50 dB scale and a 1/12th octave horizontal smoothing.
The measurements were made with a MiniDSP Umik-1 (with the calibration file) at 75 dB (pink noise).
Now I must say that it's a lot messier than the previous. The y-axis scale changes a lot the look of the curve. I'll be more careful in the feature and thanks for pointing out to me that I made a mistake!
That said, it doesn't change the fact that I'm still very impressed and happy with them. :D
*It's my first post on AudioCircle, so if something is not right tell me and I'll change it.
(https://www.audiocircle.com/image.php?id=200702)
Crutchfield customer from Cambridge, MA on 10/1/2019
Love these. Mainly classical listener. Lovely, lively balance throughout the range. Warm, with clear high end. Piano music, for example, beautifully rendered. Port plugs with center punched out helped, as recommended by KEF and various reviewers.
The best speaker that $300 could buy you
November 20, 2019
...But KEF Q150s were way over my budget at the time so I ended up with ELACs for front L/R and ELAC Debut 2.0 C5.2 for center, with Fluance AVBP2 bipole speakers rounding up my set-up as side surrounds...
I was amazed with the result. My whole system was instantly transformed. Now I am a believer in using direct speakers for surrounds, although partly it may be the Uni-Q design of KEF Q150, and other direct speakers may or may not be as good for this purpose. But KEFs worked amazingly well. They opened ELACs up, too, so I was very pleased. And they looked so sleek, too! I decided to take a further leap and replace my ELAC L/C/R with KEF Q150s. Let me tell you that results were spectacular. YPAO nailed it right away and for the first time I did not have to change anything except setting speakers to small with the crossover at 80 Hz to redirect bass to the subwoofer.
The sound was so good that I could not stop watching Dolby Atmos and DTS:X trailers on youtube. This is an amazing little speaker! Way more detailed than ELAC, well balanced and clean, whether played at high volume or low. At the original price what I did would not have been a viable project for me but with the current discount I got a sound system that I could only dream about before. KEF Q150 at $300 vs ELAC Debut 2.0 at $300? There is no contest! You owe it to yourself to get KEFs. They are in a different class than ELAC. Highly recommended.
Amazing bookshelf speakers for the price - stop looking and buy these
December 13, 2019
If you’re in the market for some bookshelf speakers at a reasonable you should stop looking and buy these. Right out of the box they need to break in so you won’t really get the full glory for about 10-15 hours. But once they are broken in they’re incredible.
I did a fair amount of research and listened to a lot of bookshelf speakers proved from $500-1200 a pair and the money these sounded as good as any pair I heard that was over $1000.
I have them in a room that is about 13’ x 9’ and they fill room with sound. Bass is punchy considering the size of the driver and the highs are clear as a bell. I’m not sure they would hold up as well in a large room but for the a small setup they’re absolutely killer...
Lotsa cost cutting there. The Q150 driver has a stamped sheet metal frame. The Q100 driver had a nice cast alloy frame.