I was going to recommend a pair of Vandersteen 3's. It's an incredibly good all speaker. They're pretty much exactly what you are asking for. That said, I think you should consider another amp before you do anything. I had a 5i myself and found it very overrated. It sounds OK with speakers that don't have a lot of detail. When you listen to it driving more detailed speakers, it fall apart. Also, it doesn't have a lot of power.
If you know anyone that will let you borrow an amp, put in your system and compare it to your Naim. Doing so should give you some good info on where you need to go.
Tannoy with Naim will give rock and roll.
I'd take a look at the PMC floorstanders in that price range that have been getting some very good reviews (I remember seeing one in Soundstage not too long ago). I think they feature transmission line bass that should satisfy your need for more complete bass response, and as the company has professional speaker roots I'd think they'd offer up good dynamics across the upper ranges as well. Not sure how they'd mate with your amp, so that's something to check out.
Since you like your Harbeths the other option would be to add a couple high quality subs from the likes of SVS, Rhythmic, etc. Of course you'd need to spend some time and $$ on integration hardware to get it dialed in right, so not sure if that's something you'd like to get involved with but it's another option.
Anyway, hope this helps and best of luck.
I contemplated adding a sub before, but it's not for me. Aside from the fact that the Nait 5i doesn't have the requisite input, I don't particularly want additional hardware, and it would take a considerable amount of time to properly dial everything in. The room acoustics are challenging enough!
To clarify, I would use my Naim electronics during the interim to offset the high initial cost. After 3-5 years, I would then purchase a suitable amplifier to match with the speakers and TT. It wouldn't make sense to buy $5k speakers and then pair them with the Nait 5i-2; I wouldn't be realizing their full potential! I quite enjoy the Nait 5i/CD5i combo, so they will eventually be reunited with my Harbeth speakers. This means that I don't need ultimate synergy with Naim, but I do need SOME synergy - I wouldn't want to listen to a poorly matched system for 3-5 years!
So, with that in mind, can someone please provide a list of perhaps 5 of the top speaker manufacturers or models given my stated criteria? I'll be doing a whole bunch of research before I actually audition anything. This opens the door to upcoming models, too!
On a separate note, has anyone run an SET amp with high efficiency horn speakers? I've never heard a horn-based system, but I'm curious to know how the sound would differ. Which musical genres would be best suited for such a setup?
P.S. I plan to make this purchase in about 2 years, so I'm still very much in the preliminary stages. This is going to be a carefully matched and well thought out system, which is why I'm soliciting input now. Thanks again!
I should have mentioned that I'm not interested in a horn-based system, just curious. I can't imagine the bass response to be anywhere near sufficient for blues/rock. I'm very curious about the mid-range, though. In my experience, the ultimate challenge for speakers is accurately reproducing solo vocals and piano. Curious to know how horns would do...
Not a floor stander - but I have been quite pleased with my Dynaudio C1 Signatures. Does a great job on your type of music.
"I can't imagine the bass response [of a horn system] to be anywhere near sufficient for blues/rock."
It depends on what type of horn system you mean. If you're talking about a single fullrange driver in a back-loaded horn, then yes the bass will be insufficient for blues/rock. If you're talking about a horn/direct radiator woofer hybrid, you'll probably have plenty of bass. If you're talking about a fullrange uber-high-efficiency multi-horn system, with a true horn-loaded woofer section, then it depends. Some will go plenty deep for rock and blues, and some will not.
"I'm very curious about the mid-range, though. In my experience, the ultimate challenge for speakers is accurately reproducing solo vocals and piano. Curious to know how horns would do..."
A good horn system will have negligible characteristic "horn" coloration, and will be extremely dynamic and articulate, to the point of doing justice to solo piano at realistic levels (which is a lot harder than it sounds). Of course not all horns are created equal, nor are all horn systems created equal - many horn systems do have that characteristic "horn" coloration, so you gotta do your homework.
The type of horn system I'm most familiar with uses a direct-radiator woofer crossed over to a constant-directivity horn at the frequency where the woofer's pattern has narrowed (due to beaming) to match the horn's pattern. The result is a "controlled directivity" speaker, and its advantage is that the reverberant energy in the room has very nearly the same spectral balance as the first-arrival sound. This is a characteristic of natural voices and unamplified instruments that relatively few loudspeakers emulate, and it's the main reason why I prefer horns (waveguide-style contant directivity horns, to be precise).
You mentioned room acoustics also... a good controlled-directivity speaker works with your room, rather than against it, in this sense: Since the reverberant energy in the room sounds like the first-arrival sound, it's beneficial instead of detrimental, and so you don't need to absorb it in order to "fix" anything. Of course you want to avoid slap-echo, but beyond that, you want a powerful, diffuse reverberant field. Indeed, the presence of a well-energized, spectrally correct, diffuse reverberant field is a primary difference between a good recital hall and the average home audio listening room. I can go into detail about some unorthodox ideas for developing that sort of reverberant field, if you'd like.
Best of luck in your multi-year quest!
I never thought I would buy a sub and I never wanted one. I now have one as of 4 days ago and it's made me a believer. I guess if you want two systems then go for it. If two systems is not suitable to your needs you should really give a sub a try. I'm using a REL B2 with C7es3's with results I only dreamed of.
Tekton Pendragons sound like they could be just the ticket, I don't have any personal experience with them but they have been very well received and there is plenty written about them. Do a search on them and I'm sure you'll be able to tell if they are a contender...
Do yourself a favor and try to audition Tyler Acoustic's new D1x. These speakers do many, many things right....the bass blows me away. It is deep, tight and defined, without ever sounding bloated or boomy. I crank up drum solos to ridiculous SPLs, and they never lose composure, and the drums sound like drums, incredible slam and impact. They can separate out a mix; I refer to it as "sorting everything out, or making sense of the music". I had some upgrades done in the crossovers (you can talk to Ty if you decide) and I used the SEAS Millenium tweeter, as opposed to the Excel offered as stock. If you can fit them in your room, I doubt you will be disappointed. (I'm also powering them with some iron, a Musical Fidelity kW 750). My only critisism: they aren't the last word in resolution, but to get that, and what they do right, would probably cost a small fortune.
Sonus Faber Liuto Tower or Sonus Faber Cremona M, new or used. I've heard the Cremona M in an extensive audition, and I *know* these would give you what you're looking for in spades.
These two have an excellent, transparent midrange that serves both acoustic pop/folk and electric blues well, from expressive voices to acoustic guitars to wailing guitars. The bass is lively and punchy. They also look fantastic.
If you have the space, you could go with Magnepan 3.7, possibly supplemented with a sub or two to bring out the kick drum and electric bass for the blues.
Eficion F300...a steal on the used market
DeVore sounds very good and are pretty easy to drive. ProAc Response series as well.
I second Duke's comments. I have Audiokinesis Prismas, you should hear the Black Keys on my system. Dynamics, timbre, ambience and plenty of bass into the low 30's, all of this with a 45 watt tube amp. At 94 db efficient,your Naim amp would have more than enough power.