Thanks to a giant favour from a new friend, I finally get to hear the Kii Threes…

A couple of Sundays ago, a large van arrived at my house containing two Kii Threes and their monumentally heavy stands, plus a pair of Linkwkitz LX Minis with subwoofers along with their knowledgeable owner, John. It was our intention to spend the day comparing speakers.

We first set up the Kiis to compare against my ‘Keph’ speakers and to do this, we had to ‘interleave’ the speaker pairs with slightly less stereo separation and symmetry than ideal, perhaps:

Setting up went remarkably smoothly, and we soon had the Kiis running off Tidal on a laptop while the Kephs were fed with Spotify Premium – most tracks seemed to be available from both services. The Kiis are elegant in the simplicity of cabling and the lack of extraneous boxes.

John had set up the Kiis with his preferred downwards frequency response slope that starts at 3kHz and ended at 4dB down (at 22 Khz?). I can’t say what significance this might have had on our listening experiment.

The original idea was to match the SPLs using pink noise and a sound level meter. This we did, but didn’t maintain such discipline for long. We were listening rather louder than I would normally, but this was inevitable because of the Kii’s amazing volume capabilities.

The bottom line is that the Kiis are spectacular! The main differences for me were that the Kiis were ‘smoother’ and the bass went deeper, and they seemed to show up the ‘ambience’ in many recordings more than the Kephs – more about that later. An SPL meter revealed that what sounded like equal volume required, in fact, a measurably higher SPL from the Kephs. Could this be our hearing registering the direct sound, but the Kiis’ superior dispersion abilities resulting in less reverberant sound – ignored by our conscious hearing but no doubt obscuring detail? Or possibly an artefact of their different frequency responses? We didn’t really have time to investigate this any further.

When standing a long way from both sets of speakers at the back of the room, the Kephs appeared to be emphasising the midrange more, and at the moment of changeover between speakers that contrast didn’t sound good; with a certain classical piano track, at the moment of changeover the Kephs seemed to render the sound* of the piano kind of ‘plinky plonk’ or toy-like compared to the Kiis – but then after about 10 seconds I got used to it. Without the Kiis to compare against I would have said my Kephs sounded quite good..! But the Kiis were clearly doing something very special.

I did try some ad hoc modifications of the Keph driver gains, baffle step slopes and so on, and we maybe got a bit closer in that regard. But I forgot about the -4dB slope that had been applied to the Kiis, and if I had thought about it, I already had an option in the Kephs’ config file for doing just that. But really, I wish I had had the courage of my convictions and left the the frequency response ‘as is’.

Ultimately, I think that we were running into the very reason why the Kiis are designed the way they are: to resemble a big speaker. As the blurb for the Kii says:

“The THREE’s ability to direct bass is comparable to, but much better controlled than that of a traditional speaker several meters wide.”

It’s about avoiding reflections that blur bass detail, but as R.E. Greene explains, it’s also about frequency response:

“What is true of the mini-monitor, that it cannot be EQed to sound right, is also true of narrow-front floor-standers. They sound too midrange-oriented because of the nature of the room sound. This is something about the geometry of the design. It cannot be substantially altered by crossover decisions and so on.

A conventional small speaker (and the Kephs are relatively small) cannot be equalised to give a flat direct sound and flat room sound. It has to be a compromise and as I described before, I apply baffle step compensation to help bridge this discrepancy between the direct and ambient frequency balances. The results are, so I thought, rather acceptable, but the compromise shows up against a speaker with more controlled dispersion.

This must always be a factor in the sound of conventional speakers unless sitting very close to them. I do believe Bruno Putzeys when he says that large speakers (or those that cleverly simulate largeness) will always sound different from small ones. It would be interesting also to have compared the Kiis against my bigger speakers whose baffle step is almost an octave lower.

However, there was another difference that bothered me (with the usual sighted listening caveats) and this was ‘focus’. With the Kiis I heard lots of ‘ambience’ – almost ‘surround sound’ – but I didn’t hear a super-precise image. When the Kephs were substituted I heard a sudden snap into focus, and everything moved to mainly between and beyond the speakers. The sound was less ‘smooth’ but it was, to me, more focused.

And this is a question I still have about the Kiis and other speakers that utilise anti-phase. I see the animations on the Kii web site that show how the rear drivers cancel out the sound that would otherwise go behind the speaker. To do this, the rear drivers must deliver a measured quantity of accurately-timed anti-phase. This is a brilliant idea.

My question is, though: how complete is this cancellation if you partially obscure one of the side drivers (-with another speaker in this case)? I do wonder if I was hearing the results of anti-phase escaping into the room and messing up the imaging because of the way we had arranged the speakers – along with a mildly (possibly imaginary!) uncomfortable sensation in my ears and head.

To a frequency response measurements oriented person, it doesn’t matter whether sound is anti-, or in-, phase; it is just ‘frequency response material’ that gets chucked into bins and totted up at the end of the measurement. If it is delayed and reflected then in graphs its effects appear no different from the visually-chaotic results of all room reflections; this is the usual argument against phase accuracy in forum discussions. “How can phase matter if it is shifted arbitrarily by reflections in the room, anyway?”.

However, to the person who acknowledges that the time domain is also important, anti-phase is a problem. If human hearing has the ability to separate direct sound from room sound, it is dependent on being able to register the time-delayed similarity between direct and reflected sound. If the reflected sound is inverted relative to the direct, that similarity is not as strong (we are talking about transients more than steady state waveforms). In fact, the reflected sound may partially register as a different source of sound.

Anti-phase is surely going to sound weird – and indeed it does, as anyone who has heard stereo speakers wired out of phase will attest. Where the listener registers in-phase stereo speakers as producing a precise image located at one point in space, out-of-phase speakers produce an image located nowhere and/or everywhere. The makers of pseudo-surround sound systems such as Q-Sound exploit this in order to create images that are not restricted to between the stereo speakers. This may be a factor in the open baffle sound that some people like (but I don’t!).

So I would suggest that allowing anti-phase to bounce around the room is going to produce unpredictable results. This is one reason why I am suspicious of any speaker that releases the backwave of the driver cone into the room. The more this can be attenuated (and its bandwidth restricted) the better.

With the Kiis, was I hearing the effect of less-than-perfect cancellation because of the obscuring of one of the side drivers? Or imagining it? Most people who have heard the Kiis remark on the precise imaging, so I fear that we managed to change something with our layout. Despite the Kiis’ very clever dispersion control system which supposedly makes them placement-independent, does it pay to be a little careful of placement and/or symmetry, anyway? For it not to matter would be miraculous, I would say.

In a recent review of the Kiis (not available online without a subscription), Martin Colloms says that with the Kiis he heard:

“…sometimes larger than life, out-of-the-box imaging”

I wonder if that could be a trace of what I was hearing..? Or maybe he means it as a pure compliment. In the same review he describes how the cardioid cancellation mechanism extends as far as 1kHz, so it is not just a bass phenomenon.

Next, John set up his DIY Linkwitz LX Mini speakers (which look very attractive, being based on vertical plastic tubes with small ‘pods’ on top), as well as their compact-but-heavy subwoofers. These were fed with analogue signals from a Raspberry-Pi based streamer and, again, sounded excellent. They also seek to control dispersion, in this case by purely acoustic means – that I don’t yet understand. And they may also dabble a bit in backwave anti-phase.

If I had any criticism, it was that the very top end wasn’t quite as good as a conventional tweeter..? But it might be my imagination and expectation bias. Also, our ears and critical faculties were pretty far gone by that point…

Really, we had three systems all of which, to me, sounded good in isolation – but with the Kiis revealing their superior performance at the point of changeover. There were certainly moments of confusion when I didn’t know which system was operating and only the changeover gave the game away. I think all three systems were much better than what you often get at audio shows.

What we didn’t have were any problems with distortion, hum, noise. In these respects, all three systems just worked. The biggest source of any such problem was a laptop fan which kicked in sometimes when running Tidal.

There were lots of things we didn’t do. We didn’t try the speakers in different positions; we didn’t try different toe-in angles; we didn’t make frequency response measurements and do things in a particularly scientific way; we listened at pretty high volume and didn’t have the self-control to listen at lower volumes – which might have been more appropriate for some of the classical music. The room was ‘as it comes’: 6 x 3.4 x 2.4m, carpeted, plaster walls and ceiling, and floor-to-ceiling windows behind the speakers with a few boxes and bits of furniture lying about.

So my conclusion is that I have heard the Kiis and am highly impressed, but there might possibly be an extra level of focus and integrity I have yet to experience. I never got to the point where I could listen through the speakers rather than to them, but I am sure that this will happen at some point.

In the meantime I am having to learn to love my Kephs again – which actually isn’t too hard without the Kiis in the same room showing them up!

Footnotes:

*Since writing that paragraph I have found a mention of possibly that very phenomenon:

“…even a brief comparison with a real piano, say, will reveal the midrange-orientation of the narrow- front wide radiators.”