Is it possible to have an accurate speaker

It's virtually academic, unless you're setting them up in a laboratory. Even the most accurate/lowest distortion speaker, when placed into the average home environment, will exhibit significant changes in frequency response due to room interaction. Just find something that sounds good to your ear in your room.

Magico is accurate.

Wolf, I so hear and feel that pain. When the folks at Meyer Sound Labs installed and calibrated their system at Yoshi's in Oakland the house reinforcement was simply stunning and throughout most of the room.

A few short weeks had past when the professional sound people began twiddling and that quality has never come close to the original setup since then.

The University Of California At Berkeley's Greek Theater is one of the crown jewels of outdoor acoustic architecture. It's simply amazing how sound companies take one look and begin hanging needles arrays totally overloading the space.

On the other hand, the crew working with the Fleet Foxes who had only heard of the Greek managed to come in and nailed it. Even the group on stage were amazed by what they were hearing.

If you know what the hell you're doing (and aren't deaf) ANY system can sound fine usually. Bands with too much stage volume are hardest in small rooms, but otherwise I find that keeping the hell out of the way with good mics, no compression, understanding trim pots, and having plenty of power amp headroom does ths job.

Many underestimate the power and headroom needed for BEST not just good results.. One of the most basic and common snafus for all audio affectionados to address IMHO.

I went to a show last summer where I asked a vendor to play some Rush on their very nice high efficiency speakers being shown off playing small ensemble acoustic jazz quite nicely off a <10 watt flea powered SET amp. It was totally underwhelming and the vendor admitted that the amp was underpowered for the task. I could have been cruel and asked for some big band jazz, but.....

For most speakers out there, 80-120 SS watts might get you in the ballpark but more is needed usually to hit a homerun regularly.

Newer high quality high efficiency Class D amps are the ticket to get there without having to deal with huge, heavy, power sucking amps. That's progress! Take advantage of it!