Hi Mapman,
I've had the Kef's for about 2 months. For the past 5 or 6 weeks, I've been rotating them in and out of the system with the P3's every 4 or 5 days. Sometimes I'll pop in the little Silverlines into the system for a day just for fun.
You are right in that the LS50's and P3's can sound very similar; sometimes surprisingly so. When I bought the Kef's I had every intention of picking between them and the P3's and selling off the ones I didn't prefer but I have to say, I just can't pick a winner. If I had to say anything definitive in my comparison, I'd say a few things:
The Kef's probably have a wider and deeper soundstage, however, the P3's image specific instruments/voices better.
The Kef's go lower
The P3's probably give a little better resolution at lower levels while the Kef's hold up better as the volume increases.
This is hard to explain, but there is something about the Kefs that make you feel like the coherency between the driver and tweeter is better. Listening to a Piano on the Kefs I realize that with other speakers, I get a feeling like the sound changes as the notes move up and down the keyboard. Sometimes with vocals, I hear the same thing. It's the first thing I noticed with the speakers when I hooked them up for the first time.
However, I do seem to prefer the sound of a violin on the Harbeths. For what it's worth, I played both Violin and Piano for quite a few years when I was younger.
The Kefs seem to interact with the room more and are more finicky in placement than the P3.
In my setup, I think there is a very slight hump in a very narrow band in the upper bass of the P3's. It's very slight, and very narrow. It's not pervasive at all and I don't always notice it when I switch from the Kefs to the P3's.
That's really it. Sometimes I'd say the Harbeths are a little more revealing (but still very sweet) in the highs but then when I listen to the Kefs again; well, then I'm not so sure; same thing with the perceived "speed".
For reference purposes, I've got a very modest system and room. Room is 11x12.5 (treated) and components are just a Musical Fidelity M3i integrated, Oppo 95 and Music Hall TT. Speakers are out from side and back walls and listening chair is too. My ears are just over 6 feet away from the tweeters. Some might call the setup quasi near field.
Music is everything except for rap, classic rock and heavy metal. I'm (obviously) not a bass freak and even though my speakers don't go low, I'm picky about the quality about what is there. Often, the bass on ported designs in my small room bug me, but not with this Kef. The Harbeths are sealed.
I suspect, but have no proof that if I had a larger room, the Kefs would start to assert themselves more, but that is just a guess and I could be completely wrong. I'd love to hear both in different rooms and settings though to learn more about their traits. I often think that my room is the worst performer in my system and do have plans for more treatment.
Again, I wish I could pick a winner and I keep listening, hoping for a breakthrough, but at this point, it might be a complete toss up. Again, maybe in a different room, things might change.
Going by looks, for me it'd be the Kefs by a mile. I love how the rose colored drivers catch the light and my attention when I walk by the listening room; as if to say..."hey, come on in and listen." I know many love the Harbeth look but umm, well....I guess their cosmetics just aren't my style. Unfortunately, it's not about the looks, but the sound and that's why I haven't been able to choose.
And now to throw another variable into the mix, I've got a low powered tube amp and high efficiency single driver speaker on order. It'll be fun to compare these new components to what I've got now. :-)
