ATC scm40 or Spendor A9

We need more information--associated equipment, room size, listening preferences and priorities, etc.

Dedicated Listening room / Acoustic treatment with rug, acoustic panel, diffusion panel.
Size room : 12 FT x 32 FT x 7 Ft (3.65 m x 9.7 m x 2.1 m)
Distance available between speaker and back wall : 1.7 FT (0.5 m)
Distance from the speaker to the listening position : 11 - 12 Ft (3.65 m)

Here my specification:

Music Server : HAP-Z1ES Sony
Preamp : Tube / Shengya / CS 6
Amplifier : Monobloc / Pure class A
Speaker Cable : Shunyata / Aeros / Stratos

What sort of speaker i can use to have the best sound :
ATC scm40 or Spendor

Not sure what your amps are capable of in terms of power or current, since you did not specify a make or model, nor can I figure from the website what specs the Spendors have. I can say that ATC speakers are among the two or three best speakers I have heard with respect to reproducing realistic dynamics, though I was listening to their powered versions of the SCM 40s. I can't speak to the Spendors, having not listened to them, though they have a reputation for being very natural, musical speakers. Hopefully others who own them can help. What do you value most in a system--musicality, dynamics? That may help you in making a decision.