Warmest sounding Green Mountain speaker?

I've had the Green Mountain Audio Callistos in my system for the past ten years and have not had the desire to upgrade speakers since that time.  Before that time I was always looking to upgrade my speakers.  If I ever do upgrade it will be to another newer Green Mountain Audio speaker.  I've listened to four of their models and they all have a very similar sound signature from the upper bass on upward.  Most of the models use different drivers but I believe the sound is so similar due to the unique first order crossover and dead quiet cabinet construction.
The speakers are very efficient, easy to drive and play very loudly.  Transparency, soundstaging (especially depth), microdynamics, inner detail, and reproduction of the human voice are extremely well done and I really haven't heard better in those areas from most other speakers I've listened to. Six moons gave these speakers a phenomenal review ten years ago.  I've had several members over my house from an audio club I belong to and all agree they are first rate speakers and cannot believe such sound quality coming from relatively small monitors.
I do agree that the monitors do not have a lot of deep bass however the bass is very tight and controlled.  I'm using a Rel Storm III sub which integrates seamlessly with the Callistos.  I'm using a hybrid integrated amplifier so I agree having some tubes in the playback chain is worthwhile.  I have not compared them to the Vandersteens.
Just my opinion.

Apart from that, the driver they use is an aurasound woofer. For the price of Rio, you would expect accuton or scanspeak revelator etc.
Not a $20 woofer!

kenjit, it's not about how much a woofer costs w.r.t. the total cost of the speaker that dictates whether or not it gets used. It's the specs & the freq response that it far more important as that tells the speaker designer how it will integrate with the tweeter & midrange. So, if a $20 woofer has the correct attributes over a $200 Accuton woofer, then, the $20 woofer will be used. I'm sure that Accuton builds good woofers but for this particular Green Mtn Audio speaker the Aurasound woofer was a better fit. I know that Roy is always looking for the best drivers & I understand that the choices are limited to independent OEMs. So, that also puts a big constraint (unless the OEM wants to order a very large batch of Accuton drivers as a minimum order from the manuf which many small OEMs cannot afford).  
I've heard a few Accuton-based speakers incl a stand-mounted Tidal - I cannot say that i was impressed with the sound. The Green Mtn Audio speakers sounded way better to me. 

There is no minimum order for most drivers including scanspeak. you could buy one single accuton driver if you wanted to.

It’s a question of getting your moneys worth. If the parts used in the Rio/chromatose only cost say $100 yet it is sold for nearly $4000 the price you pay is going towards the rent for the factory and profit. Your hard earned money isnt going into the product you are spending it on.

Now the basic Rio model costs $2800 but they are charging you $1000 bucks more for their magic wire and burn in process. Audiophiles need to be educated so that they dont fall for this nonsense. Ask for proof that any of this makes a difference.

For $4000 you could buy a whole hifi, or a pair of devaliet phantom etc.
There are many more companies now producing products using more technology for less money. If you pay $4000 and all you get is a $20 woofer a few crossover parts, and a marble cabinet, it doesnt seem to me like good value. But then again, you could also buy $4000 interconnects so its up to you whether you want to spend your money wisely or stupidly.

As I said before, if you want to feel how much distortion is going into the Rio tweeter, just put your hand on the tweeter while the music is playing and feel the vibrations. Tweeter are not designed to play such low frequencies. The seas tweeter they use rolls off at 1khz. So you should only be using it down to about 1500 if you want best sound quality. If you cut corners, then you push the tweeter beyond its limits.
This is exactly why most companies dont use just a single capacitor on a tweeter.

There is no minimum order for most drivers including scanspeak. you could buy one single accuton driver if you wanted to.

That’s not what I’ve heard. I’ve heard that a lot of the speaker driver manuf have stopped offering their drivers to OEMs OR if they do sell to OEMs their pricing is very high. This was the case for Audax woofers when they were used for Green Mtn Audio speakers. Same thing happened when Dynaudio won a large contract to outfit some European auto manuf (Volvo, I think but don’t quote me on it). Similar deal on Morel tweeters when there was a scandal concerning the Israeli & American Morel outfits.
Maybe an OEM could buy 1 Accuton driver but it’s not going to be cost effective for the OEM.

It’s a question of getting your moneys worth. If the parts used in the Rio/chromatose only cost say $100 yet it is sold for nearly $4000 the price you pay is going towards the rent for the factory and profit. Your hard earned money isnt going into the product you are spending it on.

This applies to the entire audio hobby - you’ve already alluded to the stupid-high pricing of audio cables. There’s been much written about how speakers & audio electronics is priced - 4X the manuf cost (conservatively) before it reaches you & me. Green Mtn Audio is only following the industry standard on this. I’m neither denying it nor condoning it; merely stating it. Plus, if you’ve been to the Green Mtn Audio factory, as i have on a few occasions, you’ll know that all the cabinets are hand made. There’s a lot of time spent in making each cabinet unlike many other manuf that use CNC machines. The Green Mtn Audio production is much smaller scale. So, I’m sure that this also figures into the price.

Now the basic Rio model costs $2800 but they are charging you $1000 bucks more for their magic wire and burn in process. Audiophiles need to be educated so that they dont fall for this nonsense. Ask for proof that any of this makes a difference.

Forget "asking" for proof - words do not satisfy me. I ask to hear the difference before I spend that sort of money. And, I can say that it most definitely makes a sonic difference. It’s definitely not nonsense as you wrote. Now, is it a sufficient difference for you to fork out more money? That’s upto the buyer - each one make your own choice.

For $4000 you could buy a whole hifi, or a pair of devaliet phantom etc.

$4000 for 2 (two) Devialet Phantom. Are you sure about this pricing?

If you cut corners, then you push the tweeter beyond its limits.
This is exactly why most companies dont use just a single capacitor on a tweeter.

I’ve never know Roy to cut any corners. In fact, he’s just the opposite - many of his designs never saw the production floor because he was not satisfied with the sound or the cabinet curves & lines were not just right or he was having issues with sourcing sufficient drivers to ensure replacements if a user fried a driver or drivers, etc. In such cases I would say Roy’s time to research & produce a prototype for a new model has gone down the drain to his (Roy’s) detriment i.e. he never made money on effort spent. I personally know this hence I state it with confidence. I wouldn’t call such a mentality as one who would cut corners. I believe that most of us here (& you might be included) know very little about how a good speaker is designed & manufactured.

You could try to derive the value of an hi-end audio product by summing the cost of the BOM & you will fail each time. We all know that hi-end audio is not priced that way for better or for worse. If you are in this camp of deriving hi-end audio’s value by the cost of its BOM, I ask why are you even in this hobby? You seemed to be a misplaced person & you need to find some other hobby.

And, the reason that most manuf don’t use 1st-order x-over ckts is that they simply don’t understand how to design a speaker using 1st order x-overs. It’s not easy at all & most manuf don’t have an in-depth understanding. In comparison to design with 1st order x-overs, it much simpler to design with higher order x-overs. But, if you crunch thru the math & the physics of 1st order filter design & compare it to higher order filter designs, you’ll immediately see that only 1st order filters preserve the phase relationship of one freq w.r.t. another freq over the entire audio band. No other filter does that. And, we know exactly how important it is to maintain this phase relationship over the entire audio band to ensure an accurate & realistic playback. First order x-overs weren’t chosen on a whim.
It is true that more signal bleeds over to the other driver when using a 1st order x-over simply because the filter roll-off is not that steep (compared to 2nd, 3rd, 4th & higher orders) hence one will able to feel the drivers vibrate more. It is also for this reason that most drivers' specs are not sufficient for use in a 1st order x-over speaker - the driver has to be linear for a much wider freq range. And, I believe that Roy does spend a lot of time doing deep dives into finding the correct drivers from the choices that he can afford.
If you buy an Accuton driver for a couple 100 $ that speaker will not be priced at $4000; it's going to be priced more like $20,000, if not more.