It was more a thought-experiment, how would separate dac + amp + LS50 compare to the Wireless version.
If I went the amp + passive route, I would definitely add a subwoofer, and probably not select the passive LS50 (there seems to be more interesting choices out there).
From my own experience (aka. extended tinkering and faffing about) I’ve come to realise that the KEFs position relative to your ear height is quite important. I found the KEFs highs a little brittle but that was with them at ear height. I lowered them a couple of inches and now they sound sweet as anything. Also, bear in mind that the KEFs need about 100 hrs on them to open up and settle down (some claim 200 hrs but I noticed a difference sooner than that).
You may need to move from thought to practice here. Do you have a local dealer who can let you demo the DAC you are interested in AND a pair of LS50W’s? I think that’s the only way you are going to resolve this.
However, I have one last addition for your thought experiment. I suspect you are already aware of this but its worth bearing in mind that the performance of the LS50W’s is improved over the passive LS50’s by the use of the integrated DSP/dual DAC/dual mono amp circuitry to drive the LS50 drivers to their absolute maximum (e.g. keeping frequency response flat as possible and extending the low end before roll off). It is simply not feasible to have that level of control over the LS50 drivers with any combination of external DSP/DAC/amp for $3,000.
I’ve not heard the Harbeths. I read from others that they are a more relaxed sound that don’t go as low or as loud as the LS50s (passive).
There’s a related discussion about the LS50’s compared to the Harbeths here:
May be of interest.
I listened to the passive LS50 and compared them to the passive Dynaudio X14 about a year ago, and I liked the Dynaudio X14 better. The KEF sounded a little to aggressive in my opinion, while the Dynaudio was more nuanced. I have no doubt that the P3 are much better than the LS50 passives, but they also cost twice as much.
Having said that, from what I have read the KEF Wireless version is very much different from the passive version.
There’s a shop the next town over from me that has Harbeths. When I am ready to pull the trigger (probably in a month or so) I’ll bring a thumb drive with representative music and give a listen. Maybe they’ll have KEFs, also. Wouldn’t be improbable.
As I said, I am sure you will like the P3 better, but a more interesting question is: will you like the P3 better than the KEFs if you add a musical subwoofer to the KEFs, which would put them on roughly the same price.
Btw, what about the Dynaudio Special forty? They need a subwoofer much less than the P3 does, and seem to get very good reviews. They cost a little more though.
Or a pair of Revel Concerta2 M16 (review here), and add a decent subwoofer to them (REL t7i, SVS SB-2000, etc). That paired with a Schiit Vidar and the Pro-Ject Pre Box S2 would end up at below $3000, but unlike the KEF LS50 Wireless its upgradeable in the future and much better warranty.
Soooo many freaking choices.
I have paralysis of analysis.
BTW - you sound like you’re reconsidering LS50Ws.
More choices, these with a quality sub should be excellent: ATC SCM7 or ATC SCM11. Boring look though.
Yea, a little bit, I think they are excellent but a little afraid of the quality issues. it also feels a little like if you buy them you paint yourself into a corner, unable to upgrade weak links etc. Still, looking at SQ only, they are probably the best for its price.
I haven’t found any yet 
Just remember that that that is about the passive LS50’s. I owned the passive and I got rid of them for the same reasons as many others - a bit too bright and fatiguing and thin in the middle, even with a subwoofer in my room. The actives are completely different with some warmth and no upper brightness.
Yes you can of course out an external dac into the analog ins - and did read one thread where someone said they got an increase/change? in SQ. But it still gets converted to 192/24 straight away so there will be limits.
The analog inputs on the LS50Ws gets converted to digital at 24/192 as nquery said. I did try a Naim DAC v1 into the analog vs. the USB on the Kefs (Naim fed by microRendu and also the Kefs USB; blind tested with the help of my son). Suffice to say I could hear a difference but doubt it would be classed as a statistically significant difference. I was pretty impressed that the Kefs pushed out a Naim-like sound through the analog inputs. The ADC on the Kefs is pretty much transparent (aka. extremely good).
I decided not to bother with an external DAC as the USB input on the Kef is exceptional.
A DAC to KEF LS50 Wireless seems wrong, the DAC would first convert to analog, send to the speakers, who would then convert to digital, do its DSP and then back to analog. This gives a huge penalty to external DACs, which makes it hard to compare. if an external DAC imrpoves the overall sound, it means it does that despite one extra D/A and one A/D (in other word: it would mean the external DAC is quite a lot better than the internal one).
My biggest thing is lack of control/upgradeability of the Dac given that’s where a lot of change is still occurring in the industry. I would have preferred just the active amplification but then again a lot of the amazing sound from these things is due to the digital crossover and phase alignment that occurs before the amplification. I don’t think anyone even knows what Dac chip they use, if they are upsampling beyond 192, what kind of filters they use, etc.
Yes agreed, the fixed D/A process within the speaker will always mitigate any attempts to use an external dac - what you will be left with is more of a coloration from the external dac, not an absolute increase in SQ. Even if the external dac had the best filter in the world, the internal filter is going to reintroduce side effects. I would see the analog input more as a source input for vinyl rigs than anything else.
100% agree. And having a pretty transparent ADC makes this an entirely respectable option too.
Where do you get that info from? I just googled ls50 and wm8740 and get nothing… Is it on a spec sheet somewhere??
Regardless that’s good to know. I have been tweaking my dac, recently going to R2R, and now I might give that all up for a simple 7 year old Dac chip. ugh. This is where my struggle lies!!
One thing I did realize is that if you ever wanted fully decoded MQA you might have to stick an MQA Dac in front of the analogs … ideally Roon or some other software would be able to do the full decode in software and one could pass that directly to the speakers in 192/24.
I will have to dig through my search history as this was from a few months back. I only remember as I downloaded the DAC’s datasheet at the time and happened to still have it on my laptop. IIRC it was on a pro studio forum (something like gearslutz)… so, yeh, not exactly an impeccable source…
Perhaps @ben is at liberty to comment on the Kef DAC implementation? Seeing as he has worked the closest with the Kef’s he may have more authoritative info on this…