KEF Q350 Speaker Review

[thewas]

As said, due to its nice smooth directivity EQing the LW makes also the PIR nicer and smoother, I offset the curves with EQ for -10 dB for better visibility:

If someone wants the PEQ coefficients, just send me a PM.

 

[Trouble Maker]

Are you claiming a lack of Harmany?

Ebony and Ivory
Living in perfect Harmany

I worked in a Max & Erma's (in the Columbus airport) during college and they had 1 Muzak CD that played over and over again and it had this song on it, almost 20 years later still stuck in my head. I always thought it was an... interesting choice, because you know there are going to be some racist people that come into that place from time to time (all of the time) right?

 

[echopraxia]

Longer term, I am keeping a collection of the budget speakers which I hope can be blind tested with our audiophile society here.

That would be seriously incredible data to gather. Nothing like it exists (visible to the public anyway), as far as I know.

And of course, I’m sure many of us in the area (certainly myself) would be glad to loan some of our less-budgetey speakers for such a test.

 

[napilopez]

Hmm. we already have a subwoofer preference calculator. The Burchardt that Amir didn't like also had a glitch in this region. The KEF has a glitch in the region.

What about midrange purity score?

The question would involve figuring out what range seems to correlate with subjective experiences

250 to 4000Hz?
100 to 3000Hz? (Human voice, fundamentals)
100 to 1500Hz? (Where the XPL-90 seemed to shine and was Amir's "this measures poorly but it sounds good")

One fun fact that I encountered while looking for a good FR to measure is this paper:
https://asa.scitation.org/doi/10.1121/1.2761883
which reports that some people can hear to 28 kHz provided that it's >100 dB.

I think one other failing of the preference score is that it can't really identify resonances. If a resonance really sticks out -- exacerbated by Amir's reflective room and his training at hearing them -- I think it like has a far more negative effect than deviations of similar amplitude otherwise. Doesn't matter how flat the frequency response is if a resonance sticks out like a sore thumb.

Enclosure panel resonance at ~700Hz?
Standing wave seems unlikely at those frequencies...

The ~1.2kHz resonance does not appear in the impedance plot and does not disappear off-axis, so not a diffraction effect.
Dunno...

Definitely something cabinet or port-related, methinks. Or more precisely, I find you can almost always find clues to the messiness in the 600-1500Hz region in the nearfield port response.

You can see the mess happening in Stereophile's measurements of the Q350 for instance:

Almost every speaker I've measured that has messiness in the 500-1.5kHz shows it in the port responses. Seriously, almost without fail. Get ready for a whole lot of plots:

Amphion Argon1:

And the Polk L200(more visible in the 80 degree measurement):

And the Q Acoustics 3030i:

Q Acoustics 3020i:

PSB Alpha P5:

iLoud Micro Monitor:

...Meanwhile, speakers that are clean here also usually appear so in the port response... Or at least, they show far less messiness.

Neumann KH80:

Not quite as clean as the neumann, but not quite as bad as the others, Focal Chora 806:

Not sure what exactly is the cause that this is something so recurring, but it's something I've consistently noticed in speaker to speaker.

 

[dc655321]

Definitely something cabinet or port-related, methinks. Or more precisely, I find you can almost always find clues to the messiness in the 600-1500Hz region in the nearfield port response.

Thanks for the input.

I am always suspicious of ported designs - seems difficult to get right.
Or is it just really easy to F it up on these constrained-for-space "bookshelf" layouts?
That's more of a rhetorical question...

 

[rebbiputzmaker]

Directivity control due to coaxial driver seems to create a much more of a point source which many people think they like, but was not my cup of tea.

Have you had the opportunity to listen to coaxial drivers in a stereo pair of speakers? Possibly your opinion may change. In my experience with LS 50s, and also Elac’s the stereo image is actually very broad and individuals are usually well defined within the image. Might be interesting to see if because it is a single driver the overall presentation is small.

 

[wwenze]

Let me reread the LS50 when I get the time to see the difference...

The point-source behavior sounding bad is an interesting topic. On one hand we loath room reflection, on the other hand we also like room reflection. We have headphone DSPs to make them sound like speakers. Yet a perfect speaker with no room interaction would sound like headphones.

The objectivity vs subjectivity is real with this one. Maybe we should give Bose 901 some credit?

 

[wwenze]

Science doesn’t lie.
Observations, even subjective, warrant additional investigation.

The KEF Q350 is better than the XPL 90 In many regards but the XPL90 is smoother from 100 Hz to 1500Hz or so.

Might the preference score underestimate the value of smoothness in this region compared to somewhere else (say above 16 kHz)

This is also the region where the room wrecks havoc with +-10dB peaks+dips so I'm not sure if it matters much in practice.

 

[bobbooo]

They have different rooms. This is the smaller one that I have been to a couple of times:

I think as long as speakers are always tested in the same position, then the test is valid. Otherwise, how useful would their score be if it did not apply to a typical home use?

The speakers are always positioned in front of the listener in each room though, no? My point is the often quoted statement by Floyd Toole that preference of different speakers is the same in mono and stereo (and so mono tests are applicable to typical home use) is I believe based on listening tests in which each single speaker was placed in front of the listener. We don't know for sure that correlation is the same between a stereo pair and a single speaker to one side of the listening position (for which as I said directivity effects may give different subjective results).

Well, we are going to have the data and then we will know. For now, I feel some trends are reaching to the surface in a much more controlled way than any reviewer out there. Same single speaker, in the same location with objective test data.

Oh definitely, you're controlling for nuisance variables better than many other reviewers. I mean, a lot of them do their listening tests in different rooms, with different music, volumes, speaker positions etc. One of the biggest ones is of course sighted bias though, but that is very hard to control for correctly with a robust blind test, especially by just one guy. The objective test data is of course invaluable, of huge benefit to consumers and much appreciated.

 

[beefkabob]

Are you claiming a lack of Harmany?

Well, somebody keeps playing the drums after these bad jokes. Messes with the tune.

 

[napilopez]

This is also the region where the room wrecks havoc with +-10dB peaks+dips so I'm not sure if it matters much in practice.

I personally am starting to think there's something to Amphion's approach of emphasizing the region from 2-5k, which seems to tie in quite closely with my own tastes.

The speakers are always positioned in front of the listener in each room though, no? My point is the often quoted statement by Floyd Toole that speaker preference is the same in mono and stereo (and so mono tests are applicable to typical home use) is I believe based on listening tests in which each single speaker was placed in front of the listener. We don't know for sure that correlation is the same between a stereo pair and a single speaker to one side of the listening position (for which as I said directivity effects may give different subjective results).

Though the speakers were centered for the preference studies, from what I can tell not all the research is conducted with centered speakers. The most important thing seems to be consistent coupling with room modes.

In his book, Toole describes one of Harman's test rooms -- maybe the same one Amir was in -- mentioning that the programmable speaker mover "can compare up to four single loudspeakers at one time, up to four stereo pairs, or up to three L, C, R combinations. The single loudspeakers can be compared at L, C, or R locations at varied distances from the side walls. The distance from the front wall is also a controlled variable." See figure 3.13.

In chapter 7.4.2, he talks about one of his studies on directivity, (the one about narrow vs wide and stereo vs mono) and the illustration shown has the speakers at the corners.

 

[BYRTT]

Not shure cost and performace wise KEF is really interrested do more about those resonances for Q350 in score actual looks be pretty high and better than the more costly LS50 and if they fine tuned Q350 to even better performance it would add costs and probably performance wise make it close too much in on R3 as seen in below animation, as tuga and napilopez hinted from sterophile's measurement there looks be technical proof that resonance can come from port noice but also a driver position right in the middle of a sharp edged enclosure for this combination of dimensions show heavy +3dB baffle diffraction boost centered around 1kHz point.

 

[Senior NEET Engineer]

Wait... the mono listening tests are done with speakers in the corners?

What's the point of Harman spinorama model if the first sidewall reflections arrive at different angles, delay, and level?

 

[richard12511]

These are pretty good measurements, I personally preferred the Q150 when comparing to these for similar reasons, the Q350 seemed to have too much bass and sounded too dark because of it. Having these measurements they would be very easy to EQ that out along with the resonances and probably have a very good speaker for the money.

This is the first time I've heard anyone complain about the point-source nature of a coaxial being a bad thing though, it's always sounded more natural to me than typical speakers with vertically aligned drivers.

I definitely see coaxial as a positive.

 

[Mawclaw]

Wait... the mono listening tests are done with speakers in the corners?

What's the point of Harman spinorama model if the first sidewall reflections arrive at different angles, delay, and level?

It seems like the listening tests are such an after thought compared to the data that I basically don't read them. Its crazy that much attention is given to them in the comments, especially on this website. It seems interesting to try to relate what Amir will like based on the graph but that's it.

If I was doing these listening tests I am pretty sure my reviews would be affected by a huge amount of things- did I just eat a bomb ass sandwich? Is my back sore from lifting some monster towers? etc. etc

 

[richard12511]

@amirm I'm wondering if your subjective impressions of these KEF coaxials would improve when listening to a phantom image from a stereo pair? Especially, it would be interesting to consider how the directivity of the two speakers interact in producing a "soundstage". I say this because this is the practical use-case for most of these designs. Just going down the subjective rabbit hole here . . .

Coaxials definitely produce a tighter image. Whether or not that is a good thing, I don't know.

 

[amirm]

Have you had the opportunity to listen to coaxial drivers in a stereo pair of speakers?

Many times at shows. And for a few months we had a set of KEF Blades. But no, in my controlled setting, I have not.

 

[richard12511]

I think as long as speakers are always tested in the same position, then the test is valid. Otherwise, how useful would their score be if it did not apply to a typical home use?

Based on the 3 blind listening tests I've done in my room, this seems like a flaw in the test. IME, you can't place all of the speakers in the same spot. Instead, you should place them in the spot that sounds best for that room. For the shootouts that we did, it took about 3 days of moving, measuring, and fine tuning each speaker position to find the optimal spot before the test. I understand why they have to do it that way, though, and it's better than the main alternative. I imagine it would be way more difficult to design a more flexible switcher.

 

[amirm]

did I just eat a bomb ass sandwich?

You mean your "port" interfering with the speaker's???

 

[richard12511]

Many times at shows. And for a few months we had a set of KEF Blades. But no, in my controlled setting, I have not.

Subjectively, how would you say the Blades compared to the Salon 2s. Salon 2s are one of my dream loudspeakers, but KEFs have seemed to measure really well on this site.