LS-50 Speakers (Passive)

I'm pretty sure the passive LS50s were the original version, and the wireless came afterwards.  The wireless are supposed to be better, which makes sense as the designers could incorporate DSP and match amplifiers to the drivers.

I've only demoed the passive ones, and I thought they sounded nice.  I own the Elac UB5s as well, and to my ears they're incredibly close.  The LS50s have a nicer construction and nicer finish, and I think they're a bit darker than the Elacs, but both are excellent speakers.  

The Elac UB5 is a very good speaker for the money, but it IMO it doesn't sound anything like the LS50 passive.  The imaging and dispersion pattern of the dual concentric UniQ driver on the LS50 in entirely different than the UB5, which sounds more "conventional" (not necessarily in a bad way).

While the LS50 is not my personal choice it is a superior and very distinctive speaker.  The UB5 is distinctive mainly for it's performance at it's price.  Again, IMO.

I would only get the LS50’s if you plan to also use a subwoofer (or two). They are great speakers, but they only get to 79Hz +/-3dB (ground plane, so some in room boost).

The Philharmonic “New Philharmonitor” would be my pick if you won’t be using a subwoofer. They are built to order though.

The UB5 (only addressing it as others are recommending it) has a midrange boost, and it’s imaging is pretty good, except in the 3kHz-7kHz region.

The HSU CCB-8 is very similar to the LS50, but a decent bit cheaper, and has a good amount of bass, so subwoofers aren’t a necessity.  
 
 The SVS Ultra bookshelves are also very good. However, I feel they are a bit overpriced. Via their outlet store, you can get the Piano Black finish, one being undamaged for $50 off and one with faint scratches for $100 off, they post pictures of the scratches, so that would be $850 total instead of $1000.

I have a pair of UB5s, as well as a pair of ~1978 Chartwell LS3/5As. I should compare them some time.

40 year old caps are probably suspect

crossover to my sub naturally at the point where the mains can't no longer output, and keep the use of the sub to a minimum.

crossing over an octave above the main 'lower' frequency @ 6db / octave with a passive XOver and setting sub[s] to 18db / octave and 180° with the sub[s] in the main plane yields better results than trying to get bottom out of a small driver / box. The phase is correct, the mains are not stressed and less power is required for the mains. Main and sub should be same type, i.e. sealed or vented.

C = 1 / ( 2 * π * f * R ) where f is desired frequency, R is amplifier input in Ω.
C is in farads, so multiply by 10^12 FOR pF

I have a pair of UB5s, as well as a pair of ~1978 Chartwell LS3/5As. I should compare them some time.

40 year old caps are probably suspect

Original LS3/5As can be worth $1,500 to $2,500 a pair. Modified ones ain’t worth sh*t :-)