Your room is moderate sized and if you want anything close to realistic levels, I would try and stay with 90 dB or higher. Just as important as overall efficiency is the impedence curve. Are there any frequencies at which the impedence drops significantly? You can always use Zero autoformers if that's the case, but a 6 ohm or greater nominal impedence and a smooth impedence curve will indicate an easy to drive speaker. Looking at the Europa spec, its 5.25 ohms, very smooth curve, sensitivity 88 dB. You might try it with the autoformers, or it could be OK if you don't push it hard. I would say you are right on the edge, but there are other good higher eff speakers out there that MIGHT be a better match. I only heard that amp once at a show, but it sounded great with some very good, high eff horns.
Speaker Choice for Almarro 318B
Guys, I'm a budding audiophile looking to jump up to tube amps after a few years with an Arcam/B&W integrated combo. I've become smitten with the Almarro 318B integrated tube amp and now I'm in the market for some affordable speakers that will suit the amp better than my B&W DM 602 S3 speakers. The room is approx 14'X 16', hardwood floors with a small area rug, celings are approx 10' high. Speakers will need to be placed close to the wall. I listen to an eclectic mix of music that veers from noise rock to experimental electro acoustic to HEAVY avant metal ala Sunn O))) to more traditional things like PJ Harvey and Radiohead. I'm in need of a good speaker recommendation. I've been looking into Green Mountain Audio Europas, Zu Tones, Gallo Ref 3.1s, and the Omega Super XRS speakers. Can anyone point me in the right direction here? If I had the cash I would get the GMA Callistos based on reputation, or the Zu Druids, but I don't think I even have the space for these speakers. I am leaning toward a used pair of Europas for $650 shipped. Should I take the plunge? Please help! I want a speaker that will be a noticeable step up from my current setup...Will the GMA Europas mix well with the Almarro 318B? Thanks!