Hi @tansoonlee.

Welcome to the Sonos community and thanks for reaching out to us.

Can the SONOS Amp power the non-active KEF LS50 speakers sufficiently? Anyone has experience? https://international.kef.com/products/ls50 Yes, based on the device’s specification requiring 25 - 100 W @ 8 Ohms impedance. The Sonos Amp’s power capability is 125 watts per channel @ 8 ohms. 
 

I hope this helps.

Please let us know if you still have further questions or concerns. We are always here to help.

Thanks,

I’m driving my KEF 301’s with the SonosAmp and am Thrilled with the sound. Sonos sub and 2 Sonos 1’s for surround for my home theater. GREAT choice on the KEF’s!!!

Hi @Jprice455.

Welcome to the Sonos community and thanks for sharing your comments.

@tansoonlee we have one member of the community who shared his thoughts about the speaker’s relative functionality in relation to the Sonos Amp.

Please feel free to reach out if you still have further questions or concerns. We are always here to help out.

Thanks,

Or just search in the forum:  E.g. https://en.community.sonos.com/components-228996/sonos-amp-ls50-frequency-response-graphs-brightness-crossover-loudness-eq-6822002

I’m currently using a Sonos AMP with the KEF LS50 (passive).  My experience has been that, for the most part, the AMP does well with the LS50, though it seems like it has trouble making loud sections of songs louder-enough...in other words, it seems to suffer a little dynamically.  Others have complained that the LS50s sound harsh with the AMP, though that has not been my experience - you do have to break the LS50s in, however, which may make a difference.  I also have disabled the loudness contour in the AMP, which was enabled by default.

Would you recommend this combination?

I’m looking to get the LS50 metas with the amp.  Hoping to get a demo this weekend.

I’ve been using KEF LS50s with an Arc, Sub and CONNECT:AMP (Gen 2) for some time on S2.

They work perfectly as LS+RS and produce a well-balanced, full sound.

The bigger problem I see with these speakers in a main speaker role - as with most KEF - is that at 85dB they are not very efficient and will need more amp power than others to go loud enough. The Sonos Amp should be adequate though - just an adequate as any other 100 wpc amp.

The other issue is that for full range sound they are not enough and will need a Sub. Which is fine, for those with the budget for it.

I have used my KEF Q100s for many years with a Connect Amp, and they work fine in a smaller room. They have a similar drive unit, go down lower to 50 Hz, are/were a lot cheaper, and serve fine if one does not need the LS50 aesthetic. They are just as inefficient at 86Db, but that is not a problem in the smaller room.

I can give the AMP/LS50 combination a qualified recommendation, depending on how/when/where you want to use them.  In my case, I’m using my system for casual music listening and front-channel audio for casual home theater (with Play:1s as my rear channels).  In this arrangement, the AMP+LS50 works pretty well.  The LS50s’ low sensitivity really works the Sonos AMP hard, so if you’re using these for serious 2-channel music listening, you’re probably better off with a Port and a beefier amplifier...or the LS50 Wireless.  If you’re looking to go for a more serious home theater setup, you might be happier with an Arc instead, as there’s no true center channel option with the AMP, and the music listening experience on the Sonos sound bars is still quite good (we have a Beam in the bedroom).  The LS50s with the AMP represent a series of compromises that might fall right into your sweet spot (as they did for me)...or create a system that constantly grates on you.

In my case, I actually started with the speakers.  I wanted the LS50s as a long-term purchase; my previous speakers were a set of KEF Reference 104/2s I’d had for 25 years.   Changes in life circumstances had me downsizing, and the LS50s were (to my KEF-friendly ears) the best-sounding speakers I could afford in the size class I wanted.  I chose the AMP over offerings from Denon, Yamaha, and NAD because the Sonos offered the most reliable (check the customer reviews of the NAD D3045!) and convenient (Yamaha receivers, for example, sound great, but aren’t designed to be left on 24/7, and don’t turn themselves on when you start AirPlaying to them) solution to the problem.  The ability to use it for casual home theater was an added bonus.

What other amps would you consider with the addition of a Port?  I wasn’t keen on the wireless edition because I’m concerned about KEFs ability to make updates to their software e.g if there was ever a newer version of AirPlay for instance.

I don't really see the point in using a third party amp here unless needed for connectivity features. 

I have found with Connect Amp that Sonos has architected its volume control more linearly than the typical stereo amp that goes loud early on and then does not do much beyond 60-70% other than distort. Sonos needs to be set at 70% to get the same sound levels that most such amps will deliver at 40%, thereby the latter just feeling beefier. But Sonos can be set to 100% and will keep going louder from 70 to 100 without distorting.

I am pretty sure that Sonos Amp hews to the same architectural style.

So a truly beefier amp would need to be 200 wpc plus, to give more than a 20% sound level bump over the 100 wpc Sonos, but the KEF still won't do genuine bass.

Far better would be to add a Sonos or third party active sub instead. That will make up for lack of ability for true deep bass in the LS 50, while reducing power draw from the main amp since the power hungry bass frequencies will be diverted to the sub. In such a set up the Sonos Amp will be more than enough for the inefficient KEF.

And I would first do a comparative listening test of a Sonos 5 pair to see how that stacks up against the LS50 driven by any amp. You may be surprised that better sound quality from the former may trump the LS50 aesthetic, and there will be a lesser need for a Sub.

Fundamentally, ANY passive speaker out there uses decades old tech compared to active speakers like Sonos with their separate amp dedicated to each drive unit, and active crossovers/DSP to make the whole thing integrate effectively, with or without things like True play tuning.

The aesthetic is a different matter, I agree, and is a subjective personal variable where preferences are concerned.

Had a demo of the LS50 Meta with the Sonos Amp as Seven Oaks Sound and Vision and was pleasantly surprised.  I tried a variety of songs and to be honest missed the low end in some songs.

I’m going back next week to re-demo it with a sub attached as well as to compare against the Blue Sound Node2i

Another data point:

Right now, I am listening to some classic jazz and I find that there is little to choose between a Connect Amp+ Quad 11L speaker pair and a play 1 pair + Sub in two zones of my open space living area. If anything, the latter shades the former a little because of the presence of the Sub. 

The Quads are well loved speakers in use from 2002, and still look and perform as well as ever. They definitely go deeper than the LS 50 and the mid range is also up there with my KEF pair, albeit one that is at a much lower price point than the LS 50. 

None of this is news; but the pleasant surprise is that the source for both just now is a Echo Show 8 wired to the line in jacks of the Connect Amp, with album art and voice commanded music from Spotify, with an option to also use the phone app instead of voice. I know that the source is far from Hi Res, and I don't even really care to know what the codec in use is, since the music sounds as good as I have heard from many familiar tracks where the source media were the now obsolete vinyl and SACD players.

So, buy the LS 50 by all means, but not all you pay for may be for better sound quality that will survive a blind test. 

Hi - I’d be really interested to hear how you got on with the second demo, I’m thinking about the same thing at the moment.

As an enthusiast of all things Sonos (and owner of an LS50), I think the LS50 and Sonos Amp would be an unwise pairing audio-fidelity wise. The key with the LS50 is they need more than wattage, they are picky to the amp source. The only scenario I would do this pairing is if convenience is the primary goal. Though given that scenario, you could achieve the same results with a lower model KEF (ex. q150).

What more do they need that the Sonos amp cannot deliver, as visible in the measure spec of the amp? Interesting to know.

I agree that LS 50 is vastly overpriced though, compared to the excellent Q150.

It’s the quality of amps and how the amp is able to handle sudden power demands (ex. when lower frequencies are present) also the sound signature of the DAC that complements the amp. There’s more to an integrated amp than just wattage. Looking at just wattage is like saying the engine of a McLaren 720S is the same as a Hellcat b/c they both output 700+ HP. 

Anyways, I’m sure the OP already made their choice. Also...oh yes the LS50 is sooo overpriced. lol

But the difference in the engines will be apparent in their power and torque curves, correct? These are always part of the engine spec.

So what is it about the Sonos amp that is visible in its spec that is lacking? I haven’t found anything that is.

Correct, but don’t forget you don’t just use a car’s engine, you also need the transmission to put that power down. Same goes for a stereo system, you need to a DAC to encode those 1s and 0s to an analog signal. 

Long story short, no matter how I explain this you need to listen to another system to believe. The LS50 while decent on the Sonos Amp have more to gain with a better amp. Don’t get me wrong, the Sonos Amp is a nice tidy package, but if you are looking for the best fidelity, there are other options. 

There is not one option that has proved itself to be better than the Sonos Amp in a controlled level matched DBT. Not one. Anywhere in the world. No one takes the trouble to do this, because putting out subjective opinions is easy to do and therefore, these are all that are seen. Including those that claim Sonos Amp is as good as any other, by the way.

For a recent example, see:

Of course if you were to say that even well conducted DBTs themselves are misleading, there is nothing left to discuss.

And since you are still unable to say what part of the Sonos Amp spec gives an insight into the claimed lower than best fidelity for the Sonos Amp, you are suggesting that this is some intangible attribute of the Sonos amp, that isn't to be found in the spec. Again, there is nothing to discuss in that case.

I say what I do after having used a dozen different audiophile brand stereo amps in the last two decades. All sounded the same when each was made the single variable in my then “audiophile” set up.

Can you elaborate?  What is the issue with using the Amp for the Kets?  

You are making vague statements unsupported by any fact and it doesn’t even sound like you have done this yourself. You are also acting as if people said things they didn’t.  I guess we are supposed to just take your word for it...