Best Loudspeakers for Rich Timbre?

You’re so funny when you channel the big windbag from 12 Angry Men. 😡 “No, it’s not!” “You can’t prove it!” 

audiotroy writes:So the reason why timbre is so difficult is that all systems are colored and true accuracy accross all freqencies is very hard to achieve.

True enough as stated, but I submit that the speaker/room interaction and the resulting radiating patterns have a profound influence on timbre.
It also has a profound influence when speakers have radiating diaphragms that approximate the instruments they are reproducing.
In my experience, the X.7i series Magnepans with their large dipolar radiating surfaces reproduce piano better for less money than just about any other speaker I've heard, including earlier Maggies.
I grew up in a live music environment; my mom was church organist and pianist for 20+ years; so was my sister. Her son competed in the Tchaikovsky piano competition. I used to hear him practice extensively on their family's grand piano. In 1991-3 I worked part time at a mega piano store that carried Steinway, Boesendorfer, Schimmel, Seiler, Falcone, and Mason & Hamlin concert grands. They also were skilled piano restorers, and I heard plenty of 100 to 180 yr. old restored grand pianos.

A well-recorded grand piano played through my Magnepan 1.7s astounds me every time. A part of it is the radiating surface size, but so is the radiating pattern and how the audio output energizes the room as a piano would.
If you disagree, fine. YMMV.

kosst_amojan writes:

Lots of things aren’t huge radiating surfaces. Flutes. Horns. Human voices. I certainly think dipole speakers have advantages you can’t get any other way, but they have disadvantages unlike any other speaker too.

Well, the funny thing about my 1.7s is how well it reproduces the very things you cite--flutes, horns, and voices.
I first noticed it when--soon after installing my 1.7s, I played the LP version of Holly Cole’s "Temptation" album. The song, "The Briar and the Rose," is accompanied by the Canadian Brass. The rendition of this brass ensemble was stunning, the best I’ve ever heard in my house, and only (maybe) bettered by a demo I heard of the Wilson Alexandrias.
The Magnepans are more than just dipoles. They are boxless panel speakers. They are also line sources, and their radiating patterns have nulls to the sides, keeping the rooms side walls largely out of the equation (true also of other dipoles).
There are several things about the Magnepan x.7 series that supersede all the dogma about previous maggies--grainy, lack of low level detail, hard to drive, etc. The first in the current series, the 1.7 wound up being the proof of concept of the new generation, and soon Magnepan offered the .7, 3.7, and 20.7, and a few years later, the very ambitious 30.7.
Whatever the new Maggies do for piano reproduction (which is hard to ignore), it does not affect their ability to provide stunning reproductions of a wide selection of instruments and voices.
I have been listening to mine almost daily for nearly 5 years.