KEF LS60 Wireless - Finally! a buzzword compliant wireless speaker that I would buy

It is REALY hard to build. Lots of angles.



dave

Yes, I guessed so.

What are your thoughts on the audibility of the reduced diffraction from large facets/angles?

There are compromises with everything, and the question is whether it's worth it. Your answer leads me to believe the improvements are subtle, and not worth the extra effort.

I'm in two minds of giving it a go myself, even though my cabinet maker has flat out declined to do it.
A large router + 1" roundover bit is as much work as I'm willing to do these days. But this also increases the work from a finishing point of view.

In the KEF whitepaper, clearly there's a lot of wiggles going on in the top octave, and the designers have optimised it for smooth down sloping listening window and power response. Also note, that they've omitted the Predicted In Room Response. This also leads me to believe that the diffractions effects in the 5-10Khz has limited consequence in audibility.

It's probably filter to pull out the Fabfilter and simulate...
best regards,
Thanh
 
What are your thoughts on the audibility of the reduced diffraction from large facets/angles?

We have not yet made that one work relly well. It will go under the knife soon and then get worked on again.

We have observed in the miniOnkens (with sufficient front end) what the difference in a cuboid (the CGR), a heavily chamfered cuboid (the Rectangular), and the trapezoid, with its approximation of a teardrop in the plan, that the diffraction signature decreased as the chamfers increased.

The Facets are an attempt to both get the symetrical wwMTww blade-style scheme, along with making the chamfers dramatic and in bith the horizontal and verticl planes.

There are compromises with everything, and the question is whether it's worth it.

Dependent on your skills and construction methods. Both The Facets and the Elipsa (sorry Sonos, you did nail the name) ar every nice shapes, but yes, probably over the top in terms of what it takes to manufacture. Tools and how you build will make a difference.

Unless you have a significantly good front end, and are a listener who really values DDR probablt too much effort. The big MTMs in their big cuboid are still the best speakers we have done yet. Elipsas a close.

For example, it is easy to 3D print exotic shapes.

Certainly some chamfering is worth the effort.

the Predicted In Room Response
How do you get any information from such a compromised piece of “data”. How big is the room. What is its shape. How stiff is it. What does the damping spectrum look like? Where are you going to put them? With DSP how much contol do you have over the room?

dave
 
I’d use a wire for highest quality.

AirPlay (1 and 2) is capable of ALAC (lossless) streaming up to 44.1 kHz (48 kHz for video contents).

The Chromecast Audio can now stream up to 96KHz/24bit lossless audio from compatible devices

Is the LS60 compatible.

Roon Ready (can’t find anything easily)

Bluetooth is just becoming capable of AirPlay resolution.

dave
 
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Hi Dave,

Sorry I didn’t highlight or bold the White Paper in the first post. It answers all your questions.

In short its wireless supports everything, since most are now well defined standards. Doesn’t support WISA, but perhaps a firmware update or licensing issues prevented that. Either way, the vast majority use Bluetooth or Airplay.

I’ve updated the OP to clarify.

This aversion to wires is part of the 20th century. We really need to get beyond that. I’ve stopped using wired phones or wired internet for domestic uses.

As for the estimated or predicted in-room response it’s part of the CTA2034 standard, and a mathematical calculation based on 360 degree anechoic measurements measurements of the speaker.

The standard is available here:

https://shop.cta.tech/products/standard-method-of-measurement-for-in-home-loudspeakers
 
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Yes, I guessed so.

What are your thoughts on the audibility of the reduced diffraction from large facets/angles?

There are compromises with everything, and the question is whether it's worth it. Your answer leads me to believe the improvements are subtle, and not worth the extra effort.

I'm in two minds of giving it a go myself, even though my cabinet maker has flat out declined to do it.
A large router + 1" roundover bit is as much work as I'm willing to do these days. But this also increases the work from a finishing point of view.

In the KEF whitepaper, clearly there's a lot of wiggles going on in the top octave, and the designers have optimised it for smooth down sloping listening window and power response. Also note, that they've omitted the Predicted In Room Response. This also leads me to believe that the diffractions effects in the 5-10Khz has limited consequence in audibility.

It's probably filter to pull out the Fabfilter and simulate...
best regards,
Thanh
Lazymans solution is to use minimal baffle, in other words when the baffle is size of the driver then the diffraction is same as with the driver alone, can't do any better, only "main diffraction hump" is left at and below wavelength of the driver diameter. Except any roundover smoothens the main diffraction hump a little, but the roundover has to start immediately beside the driver. If there is flat portion between driver rim and where the roundover starts the roundover needs to be bigger to be as effective as now ever longer wavelength is supported by the baffle and diffracted at the edge. Shorter wavelength than driver diameter start to beam, doesn't meet the edge and diffraction is reduced. The more the construct resembles a sphere the less there is diffraction.

Problem is when you have to crossover to smaller driver above a driver diameter wavelength and if they both are on same rectangular baffle the smaller one inevitably has more baffle around it like any classic shoebox, woofer and a tweeter. Make facets to take out that flat baffle area around tweeter and minimal diffraction occurs for tge effort, or don't put the tweeter on the same baffle at all. Problem with many tweeters is they have the 10cm ring on them for what ever reason which forces to use huge roundovers / facets to get rid of its contribution as flat baffle, lowering diffracting bandwidth, requiring bigger roundovers. Or just use a waveguide, which makes the small tweeter dome acoustically as big as woofer you are using, flat baffle area reduced right there :)

If bass woofer needs mo volume inside the box than what one gets with minimal baffle, do it like in the KEF paper, very slim and tall. The vertical edges are very short compared to wave bubble edge when it has expanded from driver to the baffle vertical edge making much less effect.

We gotta remember the wiggles in frequency response are due to sound coming later after the direct sound, baffle edge diffraction makes secondary sound source with reverse polarity and delay and interacts with direct sound either constructively or destructively depending on where you observe and at which frequency. Whether this is perceived and how is beyond me, but it is not too hard to minimize unless aesthetics / size / cost requirements are more important.
 
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Whether this is perceived and how is beyond me, but it is not too hard to minimize unless aesthetics / size / cost requirements are more important.

And this is what’s relevant, from an engineering and acoustic perspective, when I’m designing (I’m no industrial designer)

for instance, all those arrayable subwoofers- designed for concerts, nightclubs or theatres?I’m talking about 2-man lift type that used in pairs to half dozen. They “only” go to 30Hz.

eg. JBL VTX B28:

F06910ED-0A32-46D1-930B-742B8EE96237.jpeg


even the lowest note on the piano contains very little 27.5Hz content:

FFT of lowest note on my Yamaha U3 (2021 model):

976DA81A-F913-4F6D-8BD1-EDB5A10328B8.png


so chasing 20Hz may be fun; but once you’ve experienced it, you realised it basically a cone flapping in the wind. So you stop chasing 20Hz, or 16Hz or 12Hz like some of true bass audionutters amongst us.

BUT, getting that visceral thump in the chest/body is an experience that speakers provide that you don’t get with headphones, is a definitely worth chasing as a performance target. And that need good levels of output in the 30-120Hz band.

So psychoacoustics is important. For the general consumer it explains why the majority of the population are happy with MP3 or lossy audio or ~$100 bluetooth speakers, or the speakers in their new car, that only play down to 50-60Hz.

As a side note. the audio industry considers >US $300 the premium end of the audio market, and the growth in this market is in headphone consumption.

Google and Apple and Samsung, who have considerable more R&D resources than virtually everybody have difficulty convincing people to buy speakers in this price range.

Sonos is probably the only “premium” brand able to do it, and even they are releasing smaller and smaller products. The Sonos Play:5; which is $1000/pair; has had limited sales success. So I wonder how KEF will do with this one.

I’m not talking how many people buy a Wilson Master Blaster Chronosonic XXII whatever ; maybe the Crown Prince of Saudi has one; but 99% of people won’t care.

I’m talking about volume of sales and gross renevue, and how many people a company can sustainably employ.
 
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This is a cool design and from a DIY standpoint, I think growing the size to 8in wide cabinet and mixing it up and going a little more traditional separate tweeter (maybe a planar, ribbon, or AMT), a good high sensitivity midrange, and 8x opposed 6.5in woofers for a 97dB sensitive speaker with a down firing port. The woofers are opposed bipole design so you don’t have baffle step loss. The vibration cancellation is just icing on the cake. Could be passive or active. Either way, this would be fun. A good starting point might be the JBL 530 waveguide and 5in woofer as midrange. Then just build the 8 woofer box around it.
1652536566378.jpeg
 

jean-paul

diyAudio Moderator Emeritus
2002-09-20 7:20 am
Germany
This aversion to wires is part of the 20th century. We really need to get beyond that. I’ve stopped using wired phones or wired internet for domestic uses.
Maybe that is because the wire performs absolute best. Wired ethernet performs best of all. Audio performs best via wires. In the pro world everything is wired.... Wires also are green as they don't consume much power and they don't radiate RF in homes. Wires don't need passwords nor do they forget them, wires don't need configuration. Wires don't need compressing data and decompressing at the other end. Wires are way more difficult to be eavesdropped so they're quite secure. In large datacenters all is connected either via copper or via glass fiber and nothing is done wirelessly!

The wire "problem" is a marketing created one. There are notably more issues with wireless/Bluetooth and wireless/Bluetooth devices with various protocols than via wired connections. I see people stacking equipment and interconnecting them wirelessly :D If you measure equipment in a home where various wireless devices are installed close by then you will see the results of that in the audio chain. RF everywhere.

There is only 1 feature that is the decisive factor to consumers: convenience. They have their smart phones almost glued to their hands and know the drill do connect stuff wirelessly. The profit model is to lure consumers in various subscription services instead of owning anything. So the industry works together with the content providers and stuff really starts to be user friendly and also to perform OK. There is a lot of money to be made. Simple. This all has nothing to do with "the wire", the wire only costs money just once and it works its entirely life for free.

BTW the buzzwords are quite expensive, a pair of LS60 cost 6600 Euro.
 
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With all respect Jean-Paul,

i work in an environment where mobile phones and smartwatches are not allowed and I come and go via iris scanners so I understand what you mean about data integrity and risk of security compromises…

On the other hand mining trucks and drones a being driven and flown remotely via 5G and other wireless technologies.

I’m not saying they are wireless is foolproof, I’m just saying listening to audio is entertainment, and is not mission critical.

The concerns about using wireless for audio reminds of same concerns about audio running from computers in the late 20th century- Everyone still wanted to listen to their silver discs because audio extracted onto hard disc drives wasn’t good enough.

Wireless audio is not available everywhere in the world, but if you have wireless high bitrate video streamed to your television on demand, then consider that wireless audio a problem solved.
 

jean-paul

diyAudio Moderator Emeritus
2002-09-20 7:20 am
Germany
It is not being against progress, it just isn't 100% progress. It sure is big business. The things that drive or fly sure need wireless connections just like they need wheels or wings :) Audio devices in general mostly don't drive or fly away.

Devices that are in a room less than a meter away from eachother can be connected the simplest and most reliable way. Via the Wire better known as "W". Pure uncompressed audio, clear as water. Fresh as fresh can be. Smells like audio should smell, the sweet smell of youth. Green and power saving for a better world. W makes electrons flowing flexibly and happily all in the same direction through one of the most beautiful and environmental friendly materials of this planet: copper (the new gold). Use W and be happy and tell your friends. W for true quality entertainment! W is not using nasty virus like radio frequent signals that are bad for you and your family. Keep those radio signals out of your home, just use short and tidy wired connections which are the best of the best. Faster, better and more economic.

W is supported by all content providers and all subscription services too! As of today W is supported by all available chipsets. You can join W too. W is a company supported by Copper Inc.
 
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...and going a little more traditional separate tweeter...

Using a good FR as a midTweeter has already proven to be a good solution to build this lind of box. As in any proper WAW we get no XO in the critical region and it is possible to get all of the drivers within a quarter wavelength centre-to-centre. That and teh low XO point largely takes the sonic degradation that most XOs bring.

dave
 
Is TWS (true wireless stereo) going to beat a physical wire? No, but for 99% of people, the ease of use of connecting their phone to stream and not having a cable between the speakers is golden. I personally find the sound quality very acceptable for most enjoyment type listening except for critical listening like when I am comparing speakers or amps etc.
 
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