KEF Q350 Speaker Review

[tuga]

Kef has more downward tilting ER slopes than Harman, so why doesn't it sound better? Harman claim they speaker must beat all competitive spekers on the market before going into production, so their speakers must have beaten KEF's in their internal blind tests.

This is where subjectivity kicks in.

Harman's speakers must have beaten, or been preferred over, KEF's by a particular sample, small, and likely to be Harman owners or at least used to Harman sound.
And it will still be a matter of preference. Perhaps an identical research performed in the UK would yield the inverse results...

 

[QMuse]

Interestingly though John Atkinson sees the comparison more differentiated https://www.stereophile.com/content/tale-two-speakers

In that review JA seems to favor KEF for it's treble balance, which IMHO is more matter of getting EQ right to suit your personal preferences than a differences in SQ. He also mentions that M106 " could play louder than the KEFs without strain" which may point to difference in IMD.

 

[tuga]

There's nothing scientific about speculation based on Harman's marketing representations.

But even if we do assume that Harman speakers beat all KEF speakers in their blind tests, there is no evidence that this was a result of the speakers' off-axis performance.

Moreover, it would tend to invalidate the model.

And PS, how can you be so confident that KEF speakers don't sound better?

Particularly if they were assessed in mono, and as @Bjorn mentioned not in ideal conditions in regard to postioning.

 

[tuga]

Are we to conclude from this post that KEF was beaten by Harman in spite of superior spinorama and better preference score because of high IMD in the bass region?

It's far too convenient to believe that a Spinorama is enough to characterise the performance of a loudspeaker.

And the same can be said to blind A-B testing a single speaker; adequately positioning two or three stereo pairs of speakers for blind A-B testing would have been a logistical nightmare, so T&O took the easy way out and half-heartedly supported this with some favourable research.

 

[QMuse]

Particularly if they were assessed in mono, and as @Bjorn mentioned not in ideal conditions in regard to postioning.

@Bjorn provided quite a drastic example. If we assume LS50 and M106 were tested than using same positioning doesn't give advantage to any of them.

 

[tuga]

@Bjorn provided quite a drastic example. If we assume LS50 and M106 were tested than using same positioning doesn't give advantage to any of them.

I agree. I was generalising, not addressing the specifics of this situation.

 

[thewas]

In that review JA seems to favor KEF for it's treble balance, which IMHO is more matter of getting EQ right to suit your personal preferences than a differences in SQ.

Yes, in the end what accounts for SQ, as we know most is tonality, so a bless for us that have access to EQ.

He also mentions that M106 " could play louder than the KEFs without strain" which may point to difference in IMD.

Of course, the LS50 is 5" coax with actual even less woofer surface than a non-coaxial 5" vs. the 6,5" M106.

 

[YSDR]

According to Stereophile, the croossover takes place at 2.5kHz with first-order slopes which may explain the peak at 1.2kHz.

https://www.stereophile.com/content/kef-q350-loudspeaker-specifications

The port measurement may point to the likely cause of the dip at 900Hz:

https://www.stereophile.com/content/kef-q350-loudspeaker-measurements

First order slopes doesn't have opposite direction spikes in the step response like in the measurements. So according to this, we can assume that speaker doesn't utilize 1st order slopes, at least not acoustically which matters. All these are especially true if the drivers forms a coaxial point source like this KEF.
It looks more like a Linkwitz-Riley 2nd order step response where the two drivers needs to be connected with opposite polarity to be in phase and to sum flat, of course if the acoustical centers of the drivers are in the same location.

 

[QMuse]

First order slopes doesn't have opposite direction spikes in the step response like in the measurements.

Are you referring to this? That only indicates tweeter is connected in inverted polarity.

 

[YSDR]

Are you referring to this? That only indicates tweeter is connected in inverted polarity.

View attachment 64771

Okay, but first order slopes doesn't need opposite polarity from one driver if their acoustical centers are identical.

 

[QMuse]

Okay, but first order slopes doesn't need opposite polarity from one driver if their acoustical centers are identical.

It's probably a 2nd order.

 

[Juhazi]

When we look at step response of speakers, first we must know how many "ways" there are. Then the shape can tell what alignment it uses, at each xo (acoustically). Q350 is typical and good 2nd LR alignment 2-way. Check time scale too (x-axis)!

https://www.diyaudio.com/forums/multi-way/332609-improve-step-response.html

 

[Lbstyling]

I also believe in Harman test they give you sandwiches and a mask over your eyes?

The sandwiches are more important than you might think.

If you have a hot drink during an interview your 10% more likely to give the person the job.

Also, I believe I read a few years back about a large study intended to investigate institutional racism found the largest correlating factor with sentence length given by judges was how recently they had eaten!!

On a separate note: I'm quite settled in my opinion that THD (resulting in IMD) is clearly audible at lower levels than many would suggest in real world situations. In a open field, my compression drivers measuring well under 0.1% THD at 92db are way more revealing on voice than my 0.4% or so at 92 dB focal speakers. Even with the horn crossed over to the bottom half of the same speaker there is no contest. One sounds almost real, the other does not.

Nothing in the system is under -105db distortion, so is unlikely to be a contributing factor to the statement. Yet, this is not obvious on lower quality electronics.

Obviously that was a completely subjective statement, but in a open field, with a switch to instantly A/B with level matching I struggle to final another explanation.

I also find my typical listening level is much higher on a horn with big headroom, particularly on large scale classical. You can hear further into the music with higher levels at lower distortion.

 

[QMuse]

The sandwiches are more important than you might think.

If you have a hot drink during an interview your 10% more likely to give the person the job.

Also, I believe I read a few years back about a large study intended to investigate institutional racism found the largest correlating factor with sentence length given by judges was how recently they had eaten!!

Sure thing. But trust me that boobs make bigger difference.

 

[richard12511]

@Bjorn provided quite a drastic example. If we assume LS50 and M106 were tested than using same positioning doesn't give advantage to any of them.

The issue there is that the LS50 is designed to be listened to off axis. A mono test with the speaker directly in front(and on axis) gives a slight advantage to the M106.

 

[andreasmaaan]

On a separate note: I'm quite settled in my opinion that THD (resulting in IMD) is clearly audible at lower levels than many would suggest in real world situations. In a open field, my compression drivers measuring well under 0.1% THD at 92db are way more revealing on voice than my 0.4% or so at 92 dB focal speakers. Even with the horn crossed over to the bottom half of the same speaker there is no contest. One sounds almost real, the other does not.

Well it could be the distortion, but there are a lot of uncontrolled variables at play there.

Why not try digitally adding 0.4% distortion to a music signal in software and then seeing if you can reliably ABX the difference between it and the original using your horn speakers?

 

[richard12511]

The sandwiches are more important than you might think.

If you have a hot drink during an interview your 10% more likely to give the person the job.

Also, I believe I read a few years back about a large study intended to investigate institutional racism found the largest correlating factor with sentence length given by judges was how recently they had eaten!!

On a separate note: I'm quite settled in my opinion that THD (resulting in IMD) is clearly audible at lower levels than many would suggest in real world situations. In a open field, my compression drivers measuring well under 0.1% THD at 92db are way more revealing on voice than my 0.4% or so at 92 dB focal speakers. Even with the horn crossed over to the bottom half of the same speaker there is no contest. One sounds almost real, the other does not.

Nothing in the system is under -105db distortion, so is unlikely to be a contributing factor to the statement. Yet, this is not obvious on lower quality electronics.

Obviously that was a completely subjective statement, but in a open field, with a switch to instantly A/B with level matching I struggle to final another explanation.

I also find my typical listening level is much higher on a horn with big headroom, particularly on large scale classical. You can hear further into the music with higher levels at lower distortion.

Could this be due to directivity? My compression driver horns are also way more revealing than my cone and dome speakers. I kind of assumed that was due to the narrower dispersion, but perhaps distortion also plays a role.

 

[Lbstyling]

Could be the distortion, but there are a lot of variables at play there. Why not try digitally adding 0.4% distortion to a signal in software and then seeing if you can reliably ABX the difference between it and the original using your horn speakers?

I have done this before and the answer was no back then, but this was not with horns, so I must do it again! Good idea!!

I have noticed errors in playback setting that I was not aware of before. Weird things to do with PC settings like routing sound through JRiver without maxing the desktop volume first creates a close echo in the impulse. IIR filters being audiably different to PIR -without controlling phase (can't remember if this was min or linear phase control) It was always there, but I never noticed somthing was clearly wrong until using a horn.

 

[MZKM]

The issue there is that the LS50 is designed to be listened to off axis

Yet their manual shows this:

 

[richard12511]

Yet their manual shows this:
View attachment 64793

Strange. Maybe lack of communication? Different folks designing the manual than those working on the design of the speaker and/or giving placement advice.