Determining compatibility with amps

Very nice system. Duplicating is a very safe bet.

If you are going to snow bird somewhere, then you should have a great opportunity to go listen to speakers. You could make this a fun in the sun project. 
 

Speaker sound characteristics are hard to communicate via words or frequency response charts. If you talk about the ultimate output, on one end of the spectrum are highly detailed systems with great slam. These scrape the last ounce of detail from the medium… typically putting the venue and mastering techniques in the spot light (typically solid state). On the other end of the spectrum are highly musical  systems that get the gestalt of the venue and the music correctly… ones that emotionally connect you to the music (typically tube)… then everything in between… either well done or poorly done. Then there are particular characteristics of value… like slam, imaging, micro detail, rhythm and pace. 
 

So, where are your values? Your particular musical interests?

@ghdprentice Thanks.  So it turns out I'm valuing more involving, connection to the music whereas I probably went into this current venture (2016) thinking that total accuracy and slam were the hallmarks of a really "good" system.  The staging especially pulls me in so long as there is nothing off about the timbre and reproduction that seems colored.  Not a musician but lots of family are, so many days spent at events, recitals, around bands etc.  I think I still have a reference to what instruments sound like!  My choices going forward may be more size of room related and power needs.  That's why I'm not sure simply duplicating this again will work.  17x 32 great room with the listening "half" vaulted 13 ft, the rest 9ft ceilings.  

@OP. Put simply, take the manufacturer's nominal impedance for the loudspeaker and, on a precautionary principle basis, assume that it is optimistic - because they frequently are. Check the specifications for efficiency as well and also assume that they are optimistic, but most speakers are around 87dB unless they are minimonitors or specifically designed to be driven by low powered, mostly tube, amps.  Check the amp manufacturer's specifications and check out reviews as well - look for amplifiers that will double their power from an eight ohm to four ohm load - if they are solid state amplifiers. That approach should avoid the most obvious mismatches. After that its a question of budget, where you sit in the room and how much bandwidth, volume and dynamics you want. Maybe there will be more choice/listening opportunities in the area you are planning to build the second house?

OP,

Your description of journey from details and slam to musical is exactly like mine… but I am slow, it too me over forty years… over ten years with season tickets to the symphony in ideal seats and countless a acoustic concerts.

For speakers you need to listen to Sonus Faber. I have honestly never heard more natural sounding, musically compelling speakers (which also image incredibly well). For electronics Audio Research (mine is an all ARC system), Conrad Johnson, VAC, and Cary.

As has been mentioned one needs to start with speaker selection.  Which tends to be a personal preference.  And clearly efficiency will impact your amp selection. For example I have Magnepan 20.7s which are probably one of the most realistic sounding speakers where the performers appear in your room and to my personal taste, and I think would more than energize your room.  However their efficiency is low 86 db so you need lots of power to bring them to life.  In my experience greater than 250 watts in 8 ohm, 500 wt into 4ohm.  Mine are 350 into 8 and 700 into 4.  Point being cost can becomes a factor with speaker section. Suggest attending a major show or vendor for narrowing down your selection after some homework on reviews.  Enjoy the journey 

@ghdprentice in fact I did drop into a high-end dealer in AZ and heard some expensive Sonus speakers.  Indeed they impressed me but were $$$ and large floor standers.  While full range I suspect I feel that subs away from front speakers can add space to the presentation.   @salc Maggie's also another I really want to hear.  Never have, any model.  FWIW new place will be in rural VA.  Can get into Roanoke easy enough.  It'll be a fun yet a tad stressful process.  

for your room size the Maggie 20.7s would be great.  The 3.7s which I also owned and loved don't go down as much but still have the Maggie resolution and midrange magic and would also be an option.  I probably  wouldn't go down to the lower models not because of their performance but just due to your room size depending on seat arrangement.  I would check with their reps or Wendel at magnepan. Good luck

OP,

Yes subwoofers extend the sound stage on most systems… maybe all.

What kind of budget are you thinking of allocating to speakers? That might be a good place to start.....not sure what $$$ means to you

Good point, was thinking 5-7k new but ok with used.  Lots of time to research.  Was hoping to get an understanding of what true mismatching sounds like (those difficult low impedance,  hi capacitive zones).  Besides the obvious of less dynamics or spl from too low of power.  

@vthokie83 FWIW our plan to build is 45 min sw of VATech.  

Single Ended Triode tube amp with high efficiency speakers is a great way to go.  You’d be very surprised just how loud a 3 wpc 2A3 amp can get with very efficient speakers > 100 db.

But depends on the kind of music you listen too…

Well AKGWIZ a 17x 32 room, with a "half" vault of 13 ft, and the rest 9ft ceilings, is a pretty clean slate to start with. Great for long standing frequencies.

With a room that size there are numerious full range speakers that'll shine, so IMHO - kiss (keep it sweet & simple). The fancier the plumbing the more likely you'll clog the drain. So why monkey with subs if you don't have to.

Lots of files like their Maggie's, & they have their pro's, but for my ear I'd choose the big Martin Logans. Both brands love power amps, I'd say you'll get considerably more speaker from the Logans. But there's also the school of thought that lower power amplifiers sound better, for example the Classe' DR3 VHC, Mark Levinson ML-2, Krell KSA-50S, Valve Amplification Company PA90D in triode, or the  Wyetech Topaz 572.

These amps will run high efficiency speakers with a nominal impedance of 8 ohms all month. Offering transparency, attack, articulation, headroom, timbre and a soundstage that dazzles, matched with the proper speaker ....  to kill for.

Think Avantgarde, Tannoy Westminster or even Canterbury's, Volti Audio Vittora's, and don't forget the humble Klipsch K-horn.

To get the most out of any of these combinations not only requirers, but demands outstanding upstream components (garb in garb out), that said, I'm sure you already knew that.

Enjoy the voyage.

@thehorn thanks for the thoughtful and helpful opinions.  Yeah, if this project goes ahead I'm very excited to move a bit up from my current setting, as much as I think it's s outstanding already.  Seen lots of love for Qualiton valve amps so keeping eyes peeled for a 50w version.  New ones are 75w.  Trying to watch budget so used is fine.  I'll look into your suggestions too.  Plenty of time to scheme and watch listings.