Floor Loudspeaker Reviews

KEF LS60 Wireless loudspeaker They're Not Just Speakers

Sidebar 1: They're Not Just Speakers

I undertook this review thinking of the LS60s as a pair of powered loudspeakers with some additional features and concentrated on how they performed on those terms. However, their ability to accept and perform well with almost any music source puts them in a different category. They really are a complete audio system, lacking only a source.

At the most basic level, no networking is needed, although a Wi-Fi–connected smartphone is required for setup and control. You can directly connect a stereo line-level source (RCA) to the LS60 from any device, including a phono preamp, if you are comfortable with its conversion to 24/96 PCM and the obligatory DSP at the heart of the system. Since I don't have a record player, I compared this signal path using the stereo analog output of my Oppo player to that using the Oppo's S/PDIF outputs (coax and TosLink) into the corresponding inputs on the KEF. I was pleased with the sound from CDs with all three links and found it difficult to distinguish among them. Even better was the HDMI feed from the Oppo, an Apple TV 4K, or my JRiver-powered server playing local and streamed sources at up to 24/192. This bypassed my usual chain of USB, DACs, and amps. I was able to directly compare the former using the LS60s with the latter using the Blades. I found both completely satisfying, and the convenience and speedy operations of the former compensated for the greater transparency and superior soundstage of the Blades. Even the network-averse will get their money's worth from the LS60s.

Most users, however, will opt for the almost limitless options afforded by network access. The KEF Connect app is easy to navigate on an Apple or Android phone or tablet (I used only iOS varieties) as well as the remote control. Right on the home screen are groups of icons that allow you to select physical input sources (as discussed above), cloud sources (Amazon Music, Deezer, Qobuz, Spotify, Tidal, Internet Radio, podcasts), or local sources on your LAN.

All the cloud sources worked smoothly and provided subjective resolution at least equal to that of the services' own apps. On the other hand, the graphics of the streaming-service apps were more impressive. The LS60s' performance as a Roon Ready target was flawless; that is how I used them for most of this review. Streaming via DLNA from JRiver was also excellent. Finally, KEF Connect was also able to directly access and play music files from my NAS. Whether via Roon, JRiver, or directly, the LS60s played everything within the specs quoted (including DSD, resampled to 24/192 or 24/96 depending on whether the Secondary LS60 was connected by Ethernet cable or Wi-Fi), and, with multichannel sources, downmixed to stereo.

The LS60 Wireless was empowering. It played everything I threw at it, and it sounded great. What more could one ask of a music system—Kalman Rubinson

COMMENTS
georgehifi's picture
Submitted by georgehifi on February 16, 2023 - 3:44pm

Interesting Kef's on the ball and used Class-D amps everywhere but for the highs, where they used Class-A/B

I've always said in the past Class-D's Achilles heel is the highs because of the phase shift caused by the low order output filter to get rid of the class-d switching noise.
As you can see, Class-D output impedance rises in the highs because of the switching noise output filter.(blue trace)

And the worst thing is the phase shift increases right down into the upper mids because of that low order output filter for switching noise elimination (red trace)

https://ibb.co/vvhDLSn

Cheers George

Prof Speaker's picture
Submitted by Prof Speaker on February 17, 2023 - 2:42am

You don't really believe that the phase shift of only about 60° has an audible effect? There is not the slightest indication that phase shifts of such a small magnitude are audible. Also the lower damping factor has no meaning at higher frequencies (clearly above the resonance frequency of the transducer), because in this frequency range the mass character of the transducer dominates and the damping only has a meaning in the range of the resonance frequency. By the way, the damping in the high frequency range is primarily provided by the damping of the mechanical system and not by the electrical damping of the amplifier.

Glotz's picture
Submitted by Glotz on February 17, 2023 - 12:17pm

George rules.

georgehifi's picture
Submitted by georgehifi on February 22, 2023 - 1:58pm

"You don't really believe that the phase shift of only about 60°has an audible effect?"

Maybe, when it starts down in the upper mids then all the way up. Why would Kef use "A/B" for the highs and "D" for the rest. And if there's complaints of Class-D it always centers around the HF performance.

Technics bought out the mega dollar SE-R1 with 4 x higher switching frequency and therefore 4 x higher output filter for it, which also raises that -phase shift way out of the audio band. It's said to have the best top end of any amp, even pure Class-A.

Cheers George

benleo's picture
Submitted by benleo on February 16, 2023 - 4:33pm

Dear Kalman,
I have for the past few to several years closely followed the development of active/integrated streaming speakers. (For short "integrated active speakers".) I followed the D&D, Buchardt, KEF, Genelec, and others I am forgetting. I have three DACs and find each has its own sound signature. DAC selection is important to sound quality. Are there any integrated active speakers that allow for a DAC of your choice to be incorporated into the integrated active speaker? (The option to disable the integrated DAC and put your exterior DAC into the sound stream before amplified?) Wouldn't that be a fantastic add? How difficult and/or expensive would it be to add that feature? It would let you tailor the sound not just by DSP, but also be selecting the DAC used in the integrated active speaker. Your thoughts?

funambulistic's picture
Submitted by funambulistic on February 17, 2023 - 4:29am

... series of active speakers operate in the analog domain (i.e., no ADC).
https://www.elac.com/category/powered-speakers/navis-arb-51/
There may be other manufacturers, but this one comes first to mind.

Kal Rubinson's picture
Submitted by Kal Rubinson on February 16, 2023 - 4:56pm
Quote:

Are there any integrated active speakers that allow for a DAC of your choice to be incorporated into the integrated active speaker? (The option to disable the integrated DAC and put your exterior DAC into the sound stream before amplified?)

Not unless you build it yourself.

Quote:

Wouldn't that be a fantastic add?

Frankly, no. It defeats the integration of the DSP, amplification and DAC(s) in which the designer has invested so much effort.

Quote:

How difficult and/or expensive would it be to add that feature? It would let you tailor the sound not just by DSP, but also be selecting the DAC used in the integrated active speaker.

IMHO, the difficulty would greatly outweigh its value. The principle of such integrated products is that the choice and implementation of the DAC(s) (and everything else) is essential. If you want to tailor the sound, buy a different product or use DSP.

liquidsun's picture
Submitted by liquidsun on February 21, 2023 - 2:01pm

You can still use the RCA inputs of the LS60 and do the Digital to Analog conversation in external DAC. Right?

Kal Rubinson's picture
Submitted by Kal Rubinson on February 21, 2023 - 2:40pm

That means a signal chain from external D/A to internal A/D to DSP to internal D/A. If that's OK with you, you can.

MichaelVictor's picture
Submitted by MichaelVictor on February 16, 2023 - 10:00pm

"If you're in the market for speakers or even a complete system for just over $5000, the KEF LS60 demands your consideration."

With all due respect Is $7,000 just over $5,000?

sophie234's picture
Submitted by sophie234 on February 17, 2023 - 5:01am

In the review you state the sub setting of -9db. Is this the setting in the SVS app, or is it something in the LS60W app? I ask as I also use a pair of SB3000s, and I have their level set at between -20 and -28 depending on which speakers I'm using. Thanks.

Kal Rubinson's picture
Submitted by Kal Rubinson on February 17, 2023 - 6:57am
Quote:

In the review you state the sub setting of -9db. Is this the setting in the SVS app, or is it something in the LS60W app?

That was a setting in the LS60W app and so it was relative to the output of the LS60Ws. The SVS attenuator was left where it was for other use. From memory, it was probably around -10 to -15dB.

sophie234's picture
Submitted by sophie234 on February 17, 2023 - 12:59pm

thank you

georgehifi's picture
Submitted by georgehifi on February 22, 2023 - 1:59pm

"You don't really believe that the phase shift of only about 60° has an audible effect?"

Yes, when it starts down in the upper mids then all the way up. Why would Kef use "A/B" for the highs and "D" for the rest.
If there's any consistent complaints of Class-D it always centers around the HF performance.

Technics bought out the mega dollar SE-R1 with 4 x higher switching frequency and therefore 4 x higher output filter for it, which also raises that -phase shift way out of the audio band. It's said to have the best top end of any amp, even pure Class-A.

Cheers George

Scintilla's picture
Submitted by Scintilla on February 17, 2023 - 1:45pm

I recommend the LSX to my non-audiphile friends as a great one-stop system solution. I have the LS50Ws myself in my bedroom. Love them. But like you, Kal, I haven't been able to leave behind my Studio2s for anything else and I watch your reviews waiting for the one that captures your heart and wallet. I was immediately interested in this one when it was released. I am sure one will eventually come along, ut I still have a hard time imagining that I will find a system that sings like the Holo May with the Revels. I thought Revel was actually working on a DSP-based integrated speaker to replace the Ultima line? Do we have a confimration that they are still pursuing that or if it has ben dropped?

Kal Rubinson's picture
Submitted by Kal Rubinson on February 17, 2023 - 4:26pm
Quote:

But like you, Kal, I haven't been able to leave behind my Studio2s for anything else and I watch your reviews waiting for the one that captures your heart and wallet.

Actually, I have moved on from my Studio2s to KEF Blade Two Metas.

Quote:

I thought Revel was actually working on a DSP-based integrated speaker to replace the Ultima line?

I don't think we ever had any real evidence of that. When I visited Harman back in 2018, I raised the issue of an DSP-based integrated speaker with Kevin Voecks who was, at that time, Sr. Manager, Acoustic Technologies. He smiled and responded like a politician saying that it would be the logical direction. That is all I know.

avanti1960's picture
Submitted by avanti1960 on February 18, 2023 - 12:06pm

cabinet resonance control. That is off the charts phenomenal.

Benny Patana's picture
Submitted by Benny Patana on February 20, 2023 - 7:42pm

'My apartment does have Wi-Fi, but coverage dwindles at the speaker end of my living room. Consequently, upon setting the system up wirelessly, I quickly found myself dealing with dropouts and disconnections'

Ok, so KEF markets the LS60s as "wireless' speakers' but immediately Kal finds the speakers don't actually operate satisfactorily as wireless speakers in his living room, which has wireless coverage? How large is the living room?! I find this somewhat troubling to say the least ... surely this finding is something of an orange flag for those of us who might want to use the speakers as marketed? You need to be a little more rigorous in these reviews guys! Disclosure: I own the smaller LS50 wireless 2s and have been very disappointed in their wireless performance, which is glitchy to say the least.

Scintilla's picture
Submitted by Scintilla on February 21, 2023 - 9:20pm

I own the LS50Ws. In my loft, they haven't worked well with wireless; like at all. But they also don't do 24/192 without a wired connection. So, is wireless limitations really a deal-breaker for this level of speaker? I wired my whole place up and don't use wireless for anything but phone. I think that 's a better way to manage your privacy too. But this is merely my opinion. Still, if you are seriously looking at a $7000 speaker and think wireless is the best way to connect them, then you should probably look elsewhere.

israndy's picture
Submitted by israndy on November 2, 2023 - 7:59pm

You just have to have WiFi in the room you are gonna use them, like any other WiFi device. It's moving a LOTTA data so you can't have marginal reception like you could with a phone you are texting with.

I also use it from my Apple TV via the TV I often watch for any real highres stuff I wanna hear. Cannot believe how good these speakers are, and I got them for my 60th Birthday to really make them my favorite things ever. Ended up getting a clearance LG 77" C2 to complete the package, pure heaven.

Kal Rubinson's picture
Submitted by Kal Rubinson on February 24, 2023 - 2:45pm
Quote:

Ok, so KEF markets the LS60s as "wireless' speakers' but immediately Kal finds the speakers don't actually operate satisfactorily as wireless speakers in his living room, which has wireless coverage? How large is the living room?!

It's not the size of my living room but that the living room itself is 2 rooms away from the WiFi Router with intervening (steelframe and concrete) walls. In addition, the WiFi router is, probably, ~5 years old. So, the WiFi at that end of the room has always been useless as revealed by laptop/iPad/phone drop-outs there. In other words, it was a known problem.

Quote:

I find this somewhat troubling to say the least ... surely this finding is something of an orange flag for those of us who might want to use the speakers as marketed?

I did use them as marketed. After the described disappointment, I updated my WiFi setup and, then, the LS60s worked satisfactorily wired or WiFi.

james3895's picture
Submitted by james3895 on December 12, 2023 - 1:21pm

Mr. Rubinson, could you maybe elaborate on "satisfactorily" as used above? There are many who suffer from PTSD re: KEF wireless LS50s not working correctly on WIFI and would be plenty curious if satisfactorily meant zero drop outs, a drop out a day, etc. Any further color would be appreciated.

Kal Rubinson's picture
Submitted by Kal Rubinson on December 12, 2023 - 1:46pm

After I updated the WiFi in my home, as described above, I had no problems with drop-outs with it at all.

I will offer a caveat, however, in that I did use wired LAN for most of my listening out of habit.

LenM's picture
Submitted by LenM on May 17, 2023 - 4:49am

Kal: How would you use the LS60 in an immersive playback system?

Could you use six or eight of them in a ring?

What wireless speakers would you use above and below the azimuth ring?

Kal Rubinson's picture
Submitted by Kal Rubinson on December 12, 2023 - 1:50pm

I was just riffing.

You could use 5 or 7 of them at floor level if you had a way of providing them all with synch-ed digital signals using, say, a prepro with multiple digital outputs. Subs should not be a problem if you ran them off the LS60s.

I have no idea about what to use for top/above. LS50s?

sfroyen's picture
Submitted by sfroyen on March 25, 2024 - 2:01pm

The Specification page here states that the speakers are using a bass-reflex enclosure. This appears to be incorrect.

The KEF-LS60-Wireless-Whitepaper.pdf document, section 3.2.3 states: The LS60 Wireless relies on DSP equalisation to extend the low frequency response. There are no ports and all sound is produced by driver movement.

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