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KEF LS60 Wireless Just Announced

KMO

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FWIW, Stereophiles review of the LSX matched Kefs manual regarding buffer time in wireless mode. I confirmed latency basically evaporated in wired mode; it's reasonable to expect similar here although I'd hope wireless latency to have decreased at least a little given advancements since that time.
There's no inherent reason why it should be worse than either the LS50 Wireless II or KC62/KF92.

The KEF LS50 Wireless II white paper says the maximum latency is 6ms (which would be with phase correction on, and the wireless link). I'm going to guess it's about 3-4ms with phase correction off (based on Genelec's numbers for the option).

I don't know what the KC62's latency is though. I've seen a couple of sources say 0.5ms, which I'm sceptical about. My own KF92 calibration has it about 5ms ahead of the mains.

So I'm going to say 6ms worst-case, maybe better.
 

juliangst

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Supports MQA. But I don't want to support MQA. Bummer.
Every big company like kef will still support MQA or they would lose customers. Deal with it.
 

abdo123

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Almost anything is possible but that does not make it automatically expedient, in passive loudspeakers you cannot really make a positive sign EQ* so you would need to shelve heavily down all the rest of the spectrum (probably to less then 75 dB/W/M), also not really expedient to implement an intelligent/adaptive limiter on purely passive high power domain without its own power supply.
All those issues are some of the reasons why nowadays almost all subwoofers are active.

*In come cases you can gain a couple of dBs in the bass by phase rotation and resonance which has implemented in the past in some loudspeakers.
i think the sensitivity loss is trivial when you consider there are 4 drivers. if they're all wired in paralell (little extreme but we don't really know anything about these drivers) we're talking about close to 100 dB sensitivity. so 90dB sensitivitiy would make the speaker flat to 40Hz which should give a flat in-room response down to 10Hz.
 

juliangst

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I will deal with it. By not buying them. Now you go and deal with your attitude.
I‘m just not a big fan of boycotting every products that’s happens to have MQA support.
 
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ThELiZ

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A question to those more knowledgeable… Did they have to be this narrow due to some scientific reason? Or is it aesthetic? I only say because it upsets me just how narrow these are. One of the oddest looking speakers I’ve seen.
 

sifi36

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A question to those more knowledgeable… Did they have to be this narrow due to some scientific reason? Or is it aesthetic? I only say because it upsets me just how narrow these are. One of the oddest looking speakers I’ve seen.
Making it narrower was a goal of the design. It makes it easier to fit into more environments both physically and aesthetically. It was harder to make it narrower and they had to come up with the uni-core woofers to get down to the final size.
 

Daka

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I'm so poor that the only Kef loudspeakers i could (barely) afford is R3 so i never look at price tag of Kef loudspeakers - So you see, it's easy for me :) to disregard the "value" parameter.

I understand that there are people making a lot of money and it's not a problem for them.

What turns me on is engineering in every Kef loudspeaker.
Same here, I have R3 and when bought them, coming off from sounders previously, they seemed like expensive and stretched out my budget to get them.
At the moment I have different priorities for sure but maybe in some time I would save enough for buy them, 6k is a lot of dough and they need to drop my jaw to be worth my money.
 

Trouble Maker

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Secion 3.2.4 shows the bass compression:
I wonder how the bass management is (or isn't) designed to handle this.
If someone setup a sub around 96dB (brown line) and chose around 50hz, all would be good there.
1652356976486.png
Then When they went to the black (normal) line listening level all would be fine there, since the speaker will low/high pass to send to the speaker/sub.

But what happens if they then go to the orange (very high) listening level? Will there be some (small?) hole from around 50hz to 80hz?
*not that anyone listens that high on average but I imagine dynamic peaks could go that high.

1652357203696.png
 

Matias

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A question to those more knowledgeable… Did they have to be this narrow due to some scientific reason? Or is it aesthetic? I only say because it upsets me just how narrow these are. One of the oddest looking speakers I’ve seen.
To increase horizontal dispersion, to decrease chassis (and box size and shipping) costs.
 

thewas

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i think the sensitivity loss is trivial when you consider there are 4 drivers. if they're all wired in paralell (little extreme but we don't really know anything about these drivers) we're talking about close to 100 dB sensitivity. so 90dB sensitivitiy would make the speaker flat to 40Hz which should give a flat in-room response down to 10Hz.
In the passive version if wired in parallel (otherwise you loose sensitivity) even if they were 8 Ohm drivers (usually most are 4 Ohm for higher sensitivity) the total impedance would drop to 2 Ohm which is a no go for a commercial loudspeaker in 2022. Also if you place a similar sized woofer in a 3.1 liters enclosure (LS60 has a total volume for the bass drivers of 12.5 litres) you get a FR which has dropped more than 20 dB at 40 Hz so as said we are talking about rather around 70 dB which is not at all trivial, here a quick simulation I just ran with a typical 6" driver:

1652357833920.png


By the way the LS60 have FIR filters to shape better the directivity of the behind located woofers which is also not possible to implement in a passive version.
 
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JustJones

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Think I'll pre-order a pair. I'm always looking for minimalist use.
 

voodooless

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Unchecked, this would lead to significant bass distortion that would degrade the sound quality.
Luckily it's not unchecked, is it ;) They have an active feedback system to combat these kinds of things, next to the limiter that you mentioned of course.
 

oivavoi

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These actually look like THE loudspeakers to get within their budget range. Great looks (IMO), great dispersion pattern, great bass extension, fully active with streaming, no further boxes needed at all. Plus they are floorstanders, which I've always perceived as more practical than bookshelves for placement in living rooms. Great work by KEF!
 

thewas

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Luckily it's not unchecked, is it ;) They have an active feedback system to combat these kinds of things, next to the limiter that you mentioned of course.
Yes, didn't want to quote more of the paper where they write about it. :)
 

JustJones

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These actually look like THE loudspeakers to get within their budget range. Great looks (IMO), great dispersion pattern, great bass extension, fully active with streaming, no further boxes needed at all. Plus they are floorstanders, which I've always perceived as more practical than bookshelves for placement in living rooms. Great work by KEF!
Plus they have a remote control.
 

maverickronin

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FWIW, Stereophiles review of the LSX matched Kefs manual regarding buffer time in wireless mode. I confirmed latency basically evaporated in wired mode; it's reasonable to expect similar here although I'd hope wireless latency to have decreased at least a little given advancements since that time.

Edit: I downloaded the LS60 manual to check for any mention, the PDF only goes to pg 43 but the ToC extends to the 90s. I guess it's not fully baked yet? Or I'm hitting some old cache/CDN, maybe

I usually set MLSSA to examine the first 10 milliseconds of the sound emitted by a speaker, but in this case all I got was background noise. I increased the time window to 100ms and there was the speaker's impulse response, at the 52ms mark. This means that, fed an analog signal, the LSX delays its output by about 48ms. Peculiarly, when fed S/PDIF digital data, the latency was a more manageable 5ms, which means there will be no synchronization problems when the KEFs are connected to a video player's optical digital output.

48ms is already plenty to cause lipsync problems and will get even worse from upstearm room correction in an AVR or whatnot. If your AVR can output the front's coax/optical then you'd be good.
 

abdo123

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In the passive version if wired in parallel (otherwise you loose sensitivity) even if they were 8 Ohm drivers (usually most are 4 Ohm for higher sensitivity) the total impedance would drop to 2 Ohm which is a no go for a commercial loudspeaker in 2022. Also if you place a similar sized woofer in a 3.1 liters enclosure (LS60 has a total volume for the bass drivers of 12.5 litres) you get a FR which has dropped more than 20 dB at 40 Hz so as said we are talking about rather around 70 dB which is not at all trivial, here a quick simulation I just ran with a typical 6" driver:

View attachment 206222

By the way the LS60 have FIR filters to shape better the directivity of the behind located woofers which is also not possible to implement in a passive version.
I made a similar simulation with @voodooless 's Tang Band W6-1139SIF. It's a small sized bass driver so it should perform more or less similar to the drivers KEF are using (if not a bit worse).

4 drivers wired in a 2 || 2 configuration (no impact on impedance) yield a sensitivity of about 93 dB/2.83V. If we take baffle step into consideration we're looking at a speaker that is more or less flat to 60Hz with 82dB/2.83V sensitivity. With a -6dB point at around 40Hz. With excursion for days. We're not even exceeding 5mm with 500W @ 4Ohm.

1652358503252.png


1652358582972.png
 
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