HiFi News review the Kii Three loudspeaker

[Ron Party]

Just one person's opinion, but other than Kal I really can't think of one current audiophile magazine writer/reviewer whose knowledge and opinions I respect. I do see traces of the scientific method with at least some of the writers at SoundStage. This hobby would be much better represented with more Kals in it.

 

[SIY]

AudioXpress has at least two excellent reviewers.

 

[amirm]

AudioXpress has at least two excellent reviewers.

SIY, you owe us a story about what you do for them and such. How about posting something on that?

 

[SIY]

No real story, I write tech articles and equipment/software reviews. In exchange, I get test & measurement equipment on loan that I couldn't otherwise afford and enough payment to cover my costs. It's a hobby, not a profession.

Joao Martins has been nice enough to put reprints of a dozen or so of my articles on line on AX's website.

 

[Purité Audio]

An extremely comprehensive review of the Kii THREE loudspeaker from Audio Express.
http://www.audioxpress.com/files/attachment/2609

keith

 

[SIY]

How can you believe anything written by @jan.didden ? He's part of audio's Axis of Evil!

 

[firedog]

From a «scientific» point of view, the only new information in the Hifi News review is their pointing out that the accuracy of Kii’s frequency response is +/- 2.1 dB, which is short of the producer’s specification of +/- 0.5 dB.

The Kii Three is a fine speaker. But it doesn’t build trust when you lie about specifications. This comes after Kii, without explaining why, suddenly changed their low frequency specifications from 20 to 30 Hz.

Specifications should be truthful, even in the case of the producer being a new kid on the block.

You are selectively quoting the review results. The actual distortion over most of the spectrum is less, as they also pointed out, and not far from the quoted specs.[/QUOTE]

 

[svart-hvitt]

You are selectively quoting the review results. The actual distortion is less, as they pointed out, and not far from the quoted specs.

The error margin is to follow the entire frequency range, not a selection of the range.

The point is, Kii has released a speaker without any measurements to document their specifications.

 

[svart-hvitt]

I suppose we should all sell our Kiis and D&Ds and switch to Genelec then.

That’s not my point. Don’t make a straw man. My point is the speaker manufacturers don’t show any measurements to back up their claims. FWIW, DD too, claims error margin of 0.5 dB on their web page (see clip below). But I can’t see their backing up those claims with measurements.

ASR is measurement oriented, not promise oriented, so my pointing out absence of measurements is to be tolerated, wouldn’t you agree?

 

[Cosmik]

That’s not my point. Don’t make a straw man. My point is the speaker manufacturers don’t show any measurements to back up their claims. FWIW, DD too, claims error margin of 0.5 dB on their web page (see clip below). But I can’t see their backing up those claims with measurements.

ASR is measurement oriented, not promise oriented, so my pointing out absence of measurements is to be tolerated, wouldn’t you agree?

Being a manufacturer with DSP, isn't it possible to get a measurement of +/- 0.01dB - if you want? Set your microphone up, do some sweeps, adjust a lookup table or whatever, do some more sweeps. Print out nice ruler-flat graph. The only limits are the noise in your room, the stability of the air temperature and humidity, etc. It doesn't mean that if you move the microphone 1cm from where it was, the measurement will stay the same - but no one's too bothered about that...

I am more interested in the thinking behind the design. If the manufacturer tells me that the frequency response is defined by some arbitrary lookup table, I'm happy. If he shows me that his cardioid doodah works pretty well without any unwanted side effects, I'm even happier. If he shows that the drivers are sealed, corrected for phase and timing, and are blended with a pragmatic crossover filter, I'm happy. If his bass drivers are corrected with motion feedback I really want to hear how good that sounds. And so on.

This is different from a manufacturer who mates a 1" tweeter with a 10" woofer in a veneered box and tells me that however it measures "It's musical".

 

[andreasmaaan]

Keith, you are setting the bar low here.

The Kii Threes are €10.000 speakers.

The Genelec 8350 are €3.000 speakers.

Besides, you are a dealer of Kii, and yet you - on a scientifically bent audio formum - talk about your preference for the sound of Kii.

Again, what is the big takeaway from the Hifi News article is the fact that the test couldn’t reproduce Kii’s official specifications on frequency response. The testers measured deviations that were four times bigger than Kii’s stated specs.

Probably no big issue sound wise. But misstating specs doesn’t build trust.

Having said that, the stated specs of frequency response +/- 0.5 dB would have been (probably) a world record. If you publish specs that are «world record» material, you should - in my view - be very sure that those records can be reproduced by others. Being able to reproduce is a cornerstone in science.

+/-0.5dB is excellent but not so remarkable for an active speaker.

2dB is within experimental error for speaker measurement in a non-anechoic environment (or even anechoic if no measurement distance is specified). Or ofc if the mic is not precisely on axis.

What’s this about Kii changing the -3dB point though?

 

[svart-hvitt]

+/-0.5dB is excellent but not so remarkable for an active speaker.

2dB is within experimental error for speaker measurement in a non-anechoic environment (or even anechoic if no measurement distance is specified). Or ofc if the mic is not precisely on axis.

What’s this about Kii changing the -3dB point though?

@andreasmaaan , you wrote:

«+/-0.5dB is excellent but not so remarkable for an active speaker».

Can you show us a speaker whose anechoic measurement error is plus/minus 0.5 dB?

A CAD based computer simulation is not counting, though I suspect that’s what’s been used in these cases.

I would be very surprised if you could show anechoic errors that are 0.5 dB or less over the relevant frequency range.

PS: We need to distinguish between theory and empirical fact. Of course, a zero error product can be made in theory. Reality is another case altogether.

 

[andreasmaaan]

@andreasmaaan , you wrote:

«+/-0.5dB is excellent but not so remarkable for an active speaker».

Can you show us a speaker whose anechoic measurement error is plus/minus 0.5 dB?

A CAD based computer simulation is not counting, though I suspect that’s what’s been used in these cases.

I would be very surprised if you could show anechoic errors that are 0.5 dB or less over the relevant frequency range.

PS: We need to distinguish between theory and empirical fact. Of course, a zero error product can be made in theory. Reality is another case altogether.

To be clear, I didn’t mean +/-0.5dB was common, just that’s it’s relatively easy to achieve with DSP so long as the measurements are accurate in the first place. This is what I meant by “unremarkable”.

In fact, the bandwidth of the deviations is much important than their magnitude, so e.g. a +/-3dB speaker may in fact be more neutral than a +/-0.5dB speaker. What happens off-axis is of course also critical.

But my point is that once the drivers’ response has been measured, it is not very difficult for a designer to create an extremely flat on-axis response with DSP.

I don’t think in most cases there is any audible reason to get as close as 0.5dB provided any peaks/dips are sufficiently narrowband, however.

But I guess you already agree with all this anyway?

 

[svart-hvitt]

To be clear, I didn’t mean +/-0.5dB was common, just that’s it’s relatively easy to achieve with DSP so long as the measurements are accurate in the first place. This is what I meant by “unremarkable”.

In fact, the bandwidth of the deviations is much important than their magnitude, so e.g. a +/-3dB speaker may in fact be more neutral than a +/-0.5dB speaker. What happens off-axis is of course also critical.

But my point is that once the drivers’ response has been measured, it is not very difficult for a designer to create an extremely flat on-axis response with DSP.

I don’t think in most cases there is any audible reason to get as close as 0.5dB provides any peaks/dips are sufficiently narrowband, however.

But I guess you already agree with all this anyway?

I don’t think we’re in major disagreement.

But my request was simple:

SHOW US A SPEAKER WHOSE ANECHOIC FREQUENCY ERROR MARGIN IS PLUS/MINUS 0.5 dB.

The reason I ask is I don’t think such a speaker exists.

The smooth frequency margin in anechoic chamber is the number one benchmark for speaker designers. Toole and many others have shown that’s a good benchmark. And that explains why some obsess about having the lowest error i.e. highest precision, accuracy, to the extent that they claim the world record in smallest frequency response error without bothering to support the claim with measurements. So we need to separate marketing and promises from measurements.

Having said that, I think it’s a negative if a manufacturer makes a claim he cannot support with measurements. And I also think it’s negative if manufacturers produce less measurements today than some manufacturers made 30-40 years ago. If this is accompanied by claims of the product being full of inventions and innovations, while a literature and product review would reveal that the innovations are in fact 20-30 years old, I think ASR should be a place where we stop a little, and take a step back to separate marketing from facts.

 

[andreasmaaan]

I don’t think we’re in major disagreement.

But my request was simple:

SHOW US A SPEAKER WHOSE ANECHOIC FREQUENCY ERROR MARGIN IS PLUS/MINUS 0.5 dB.

The reason I ask is I don’t think such a speaker exists.

The smooth frequency margin in anechoic chamber is the number one benchmark for speaker designers. Toole and many others have shown that’s a good benchmark. And that explains why some obsess about having the error i.e. highest precision, accuracy, to the extent that they claim the world record in smallest frequency response error without bothering to support the claim with measurements. So we need to separate marketing and promises from measurements.

Having said that, I think it’s a negative if a manufacturer makes a claim he cannot support with measurements. And I also think it’s negative if manufacturers produce less measurements today than some manufacturers made 30-40 years ago. If this is accompanied by claims of the product being full of inventions and innovations, while a literature and product review would reveal that the innovations are in fact 20-30 years old, I think ASR should be a place where we stop a little, and take a step back to separate marketing from facts.

Well I'm not going to produce such a speaker for you because I never claimed that such a speaker was common, which seems to be the assumption behind your request. (Shall I put that in capslock to make it clearer?)

Nor do I think such a speaker would necessarily be more neutral in the frequency domain than another speaker with e.g. +/- 1 or 2dB. This is the other reason I don't think +/-0.5dB is particularly worth remarking upon.

Toole's research shows that narrowband dips of greater than 0.5dB are inaudible. This is why I wouldn't bother aiming for +/-0.5dB unless you're looking at wideband peaks and dips. There's just no point when it comes to narrowband response dips. Although if it's easy you may as well do it, assuming a linear off-axis response (which is never going to be the case to that level of accuracy with real speaker drivers).

I agree about product claims. But the difference between Kii's claims and the magazine's measurements here is likely to be down to one or more of the following:

• measurement error
• differing measurement distances
• differing axes of measurement (even if only by 1° or 2°)

 

[Purité Audio]

Another excellent Kii review from Mitch Barnett for ‘Computer audiophile’.
https://www.computeraudiophile.com/ca/reviews/kii-three-loudspeaker-review-r735/

 

[andreasmaaan]

@svart-hvitt I just want to clarify my post a little further. I hope I don't come off as irritated or whatever

I just want to expand a bit on my previous post to hopefully add a bit of clarity.

When you measure a single driver on- and off-axis, you'll notice that even the best-performing and most linear drivers exhibit little response deviations of usually more than 0.5dB, even when moving the mic position just a few degrees.

Given that this is the case, getting your on-axis response to +/- 0.5dB (even if that level of accuracy were audibly preferable to e.g. +/- 1dB) would not necessarily result in the best (i.e. most neutral) frequency response.

This is because a driver might be e.g. +1dB at 2° relative to its response at 0°, and +1dB again at -3°.

Better then to take a lot of measurements close together (e.g. at 2° increments from +10° to -10°) and then use DSP to flatten the composite frequency response of all these measurements. Doing so will almost certainly result in some narrowband peaks and dips of more than 0.5dB at 0°, but the result will be a more neutral speaker than one that measures strictly +/-0.5dB on-axis.

EDIT: I've been trying to find a good example of this online. Unfortunately the best I can do is a speaker measured at 5° increments (it's the Genelec 8351A measured by 3D3A Labs at Princeton). It's clear though that you see plenty of 1 or 2dB peaks and dips from -5° to 0° to +5°.

Look at that on-axis c. 2dB dip @ 6KHz. They've apparently decided to have it there because at -5° and +5° the tweeter is once again flat. If the designer had chosen to bump up that 6KHz dip to flatten it, the outcome would be a less neutral speaker, even though it would now have less linear on-axis response on paper.

Ditto the more broadband on-axis dip throughout most of the top octave. There may be other variations not captured by the 5° measurement increment chosen by 3D3A.

 

[Cosmik]

SHOW US A SPEAKER WHOSE ANECHOIC FREQUENCY ERROR MARGIN IS PLUS/MINUS 0.5 dB.

The reason I ask is I don’t think such a speaker exists.

The smooth frequency margin in anechoic chamber is the number one benchmark for speaker designers.

Did my post above not convince you? It is guaranteed that a speaker can achieve any arbitrary response as long as the microphone isn't moved after a calibration phase.

If you think that's cheating, as long as the manufacturer places the microphone and speaker back in exactly the same positions, the frequency response will be just as ruler flat as before.

Flat frequency response after a calibration phase is trivial with DSP. Change the volume, maybe it begins to fall apart. Move the microphone, ditto. But your precise stipulation above is trivial to achieve.

 

[andreasmaaan]

Did my post above not convince you? It is guaranteed that a speaker can achieve any arbitrary response as long as the microphone isn't moved after a calibration phase.

If you think that's cheating, as long as the manufacturer places the microphone and speaker back in exactly the same positions, the frequency response will be just as ruler flat as before.

Flat frequency response after a calibration phase is trivial with DSP. Change the volume, maybe it begins to fall apart. Move the microphone, ditto. But your precise stipulation above is trivial to achieve.

Yeh SPL differences are another possible source of discrepancy between Kii and Hifi News that I hadn't even thought of.

 

[Soniclife]

SHOW US A SPEAKER WHOSE ANECHOIC FREQUENCY ERROR MARGIN IS PLUS/MINUS 0.5 dB

As the others are pointing out I don't see this as important, but the largest Eve audio seems very close to this (@ 1/6 Oct smoothing), except at the very bottom end.

I expect you can achieve anything with statistics in this area if you wanted to.