  Coherent properties of the baryon-photon fluid decoupling are considered in
the terms of an effective nonlinear Schr\"{o}dinger equation for a macroscopic
wave function that specifies the index of the coherent state. Generation of a
transitional acoustic turbulence preceding formation of large-scale condensate
in the plasma and its influence on the CMB power spectrum has been studied. A
scaling $k^{-1}$ law is derived for the CMB Doppler spectrum $E(k)$
(angle-averaged) in the {\it wavenumber} space, for sufficiently large
wavenumber $k$ and for the weak nonlinear and completely disordered initial
conditions. Using the recent WMAP data it is shown that the so-called first
acoustic peak represents (in a compensated spectral form) a pre-condensate
fraction of the spectrum $E(k)$ at a rather advance stage of the condensate
formation process.
