LS-50 Speakers (Passive)

I own the LS50s for two years and it’s a very well balanced speaker. You won’t be able to hear anything bulging or missing unusually or unnaturally. Very well behaved speaker, I won’t repeat other users’ findings about soundstage coherence and imaging. Its hallmark is the midrange, but bass is quite satisfactory depending on the room size and placement. The highs are nice too, but I’ve heard more refined or maybe artificially more elevated twitters that add a sense of airiness, but at the account of being forward. LS50 is quite in the middle, neither forward not laid back. Pianos sound very natural on LS50 and that was my starting requirement.
Take my highs impression with a grain of salt as I’m using the LS50s with an amp of my make that is based on old school of high gain high feedback AB class.
KEFs so transparent, that I easily hear a difference when I roll opamps in my amp. Switching the amp altogether with my old Marantz is easily heard by anybody, not just by attentive ears.

On the negative sides, this is a tricky speaker to position and mate with the sub(s). It has a very strange bass dispersion pattern, where lateral or generally off-axis bass propagation is in my opinion quite stronger, so you end up with a very clean and lean bass in the listening plane and tons of bass in certain areas of the room, well off-axis. For my taste, I’m lacking the midbass hump for a better impression of size. Its lower bass, is actually quite heavy and gives nice slam impression.
Also, LS50 do have the tendency to sound better on higher volume.

With the end net sound being very dependent on the amp, I wanted to shortcut the amp matching game, sell them and buy the new wireless version, which I listened positively  at "High-end" in Munich last year.
I had a chance to hear a pair of out of the box LS50w last week and they completely put me off of my previous decision. They were nowhere near the mids and highs perfomance of the passives. I guess they really need a long break-in period to start working, but I didn’t want to risk with that.

So, to sum up, if you have a small to medium size room, you will be hard pressed to find anything to complain about the LS50. In larger rooms, the midbass energy drops quite a bit and you will need a solution for that. I haven’t found it yet because it’s not the low bass or sub bass that is missing but the midbass. My sub helps add weight but not in the upper bass and I cross the sub quite high at about 100Hz. Then again, the placement of my LS50s and the sub is far from ideal.
Maybe someone will help with an idea of a sub or bass that covers not only the sub range and has a very good managment of the bass.

^There’s a good chance your LS50s are placed on a room mode. If your speakers are somewhere between 2 and 3 feet from the forward wall, this is likely the case. These distances typically result in an upper bass null. It’s unfortunate because that distance allows decent soundstaging while remaining aesthetically acceptible. You might try moving the speakers to less than 20" from the forward wall (of course this will cause imaging to suffer) or try moving them 5 to 6 feet from the wall (measured to the centerline of the speaker cabinet).

I just don’t get why anyone would buy a speaker with a 6.5” woofer in a <1 cu.ft. box and expect it to move the earth. Nor do I understand why you would then try to marry it to one or more subwoofers and expect no ill effects on the sound quality. If you’re after full range sound, buy a full range speaker with a big woofer in a big box. There’s a reason that there were very few subwoofers before the advent of “home theater”. That’s where they belong.

@helomech: thanks for the advices. Actually I am keeping them closer to wall with exactly the effect that you describe. But anyway, wherever I tried in my irregularly shaped medim soze room, I still develop some string modes. This is not exclusive to LS50, I tryed other seakers.

@ripkeith: two reasons. The first is price and the second is the fact that I’m living in an appartment with weak acoustic isolation. My idea was to use the speakers w/o the sub in the quiet hours and with the subs in more noise tolerant hours. Let alone space requirements of larger floorstanders.

btw, I don’t really listen to music that requires earth trembling bass. I use my sub very subtly to just add some foundation to the mains when there is such content in the music I listen.

Just put away the Totems this morning in order to listen to the Elac ub5, and wow am I impressed. Bass output is top notch, imaging and soundstaging are setting a really HIGH bar, not that much less than the LS50s.
Some have mentioned that the LS50s do show what they really are capable of with top notch amplification - no doubt. But that should go for the UB5s as well. The UB5s are a 3-way speaker. For the money, I repeat, the UB5s kill the LS50s in the bass/mid-bass department... and the rest of the frequency range is not too far off.
Obviously, the finish and front baffle of the LS50s outclass the cheap ELAC. But on sonics alone, not really.
I am saving money for the Adante AS-61.  Can't wait.