best speaker?

Let me clear some stuff up:

Mark Levinson and Revel is a Pathetic combination, etched and dry, unless you like audio special effects over music then steer clear of Revel. And the Revels are not built on Levinson equipment at all. Remember Kurt's amplifer is 10 years pre-Revel and has little more than the same name on them in common. Your 331 sounds nothing like a No. 23 and is nearly 1/3rd the power. I would recommend getting a No. 23 or 23.5 if you desire the Revels. Your 331 cannot hold a candle to them in this application.

Your best bet with a thread like this is suggest what it is you want to upgrade about your Thiel 3.6's. Some of the speakers you suggest are very similar to the Thiels you own and may not be a worthwhile upgrade in your own opinion. Plus what price range are you really in $6000 or $12,000?

Tire guy is right about your amp which won't work from a power stand point with any speaker you chose except the JMLab which will likely give you an ill matched tonal balance to the bright side. .

Well your 331 may not be a problem and I can tell you that the Revels do not have a "liquid" midrange.

If I owned your electronics and had your taste in music and with your complaints about the Thiels, speaker to look at would be

ATC SCM100ASL (has amplifers built in so 331 would compensate for this units additional cost)
Wilson Sophia
Dali Euphonia 4
JMLab Mezzo Utopia/ Nova with YBA amplifier
Wilson Benesch Curve

Speakers Not in any particular order:

The Sophia and the JMLAbs both have a definite sound to them which you may or may not like...a love it hate sort of thing. but they could possibly be what you are looking for.

The others are excellent and are similar somewhat in basic character to the Thiels, the ATC's are the most Dynamic and coherent but the least known, The Dali is not as perfect as the ATC which with the kind of music you like might let it shine in this specific situation. The Curve is a wild card, this one might be the one that works the best with your equipment, hope you have a dealer nearby.

The ATC and Wilson Benesch would be my preferences in your situation.

As a personal aside I have been disappointed with the Revel Studio and Ultima. I have never liked them because of the ridiculously designed crossover (IMO, 1,000 micro farads of capacitance and 60 mH of induction is not a recipe for sonic success) they have between the bass and midrange. The Revel should have an active crossover and not a passive one and the timing problems are evident as the bass seems to lag the midrange. The F30's are a steal I have liked the F series a great deal even though it has a bit of tizz in the highs.

Unfortunately audio companies are afraid that people won't buy powered speakers so they make huge compromises to give the public what they expect.

Hope that helps a little, I hate when I have to turn someones list upside down but speakers in particular are not something you want to buy by the label and none of the speakers you listed seemd to fit closely what you wanted and the equipment you already owned.

Kurt,

Is this what you saw when you went on tour at the northridge plant? Things might have changed since I went there 4 years ago. Kurt, Harman makes many amplifier lines, and they didn't use Levinson when I went there.

I said it was my personal bias about the sound of the Revels and how they are designed and since I design loudspeaker as a part time vocation I asked Revel designers about this fact. And the reason they are not active in the bass and world class is because they think it would be an obstacle to selling the speakers. Which is true, unfortunately.

Kurt I know is short of the technical facts to understand what 100 mh of coils and 1 farad of capacitance will do to modern amplifiers and the sound but he maybe right that my language was too strong. Although I stick by ridiculous....and Classe amplification and even Bryston 7B's punished the Levinson amps on the Revels.

Kurt... Thiels are time aligned shallow sloped speaker design that is impulse response time coherent, everything the revels are not.

Having been a Thiel, Revel dealer everyday at work for 2.5 years I got to hear the differences. I'm not a way out guy and my "opinion" is reinforced by many many people confirming my impressions while sitting with me considering a purchase.

Are the revels bad speakers...absolutely not,,,,could they be way better than they are now...yes which is why I have a certain level of frustration with them. Cause no one bought them when they bothered to listen to the Dynaudios, someone making a purchase is not an opinion its a fact. And the revel and the thiels for that matter could overcome the Dynaudios if you want to know the truth when it came to putting the money down.

I'm not God nor pretend to be but I do have the facts.

I'm way ahead of you and have facts.