1. A method for sound spatialization, comprising the application of at least one transfer function with room effect to at least one sound signal, said application amounting to multiplying, in the spectral range, spectral components of the sound signal by the spectral components of a filter corresponding to said transfer function, each spectral component of the filter having a temporal variation in a time-frequency representation, wherein said spectral components of the filter are ignored, for said multiplications of components, beyond a threshold frequency and after at least a given instant in said time-frequency representation, and wherein, for an implementation by a sound spatialization module receiving a plurality of input signals and providing at least two output signals, in order to provide each output signal, a transfer function with room effect is applied to each input signal, each of said output signals being given by applying a formula of the type: O k = ∑ l = 1 L ⁢ ⁢ ( I ⁡ ( l ) ⁢ * [ 0 ; … ⁢ ; f k ⁡ ( l ) ] ⁢ A k ⁡ ( l ) ) + ∑ m = 1 M ⁢ ⁢ ( z - iDDm · G ⁡ ( I ⁡ ( l ) ) · ∑ l = 1 L ⁢ ⁢ ( 1 W k ⁡ ( l ) · I ⁡ ( l ) ) ) ⁢ * [ 0 ; … ⁢ ; f k ⁡ ( m ) ] ⁢ B mean k ⁡ ( m ) O k being an output signal, and k being the index relating to an output signal, l ε[1; L] being the index relating to an input signal among said input signals, L being the number of input signals, and I(l) being an input signal among said input signals, A k (l) being a transfer function with room effect, specific to an input signal, B mean k (m) being a general transfer function, with room effect, common to the input signals, W k (l) being a selected weighting factor, and G(I(l)) being a predetermined power compensation gain, z −iDDm being an application of a delay, counted as the number of blocks of samples, corresponding to a time difference between emission of a sound in a room corresponding to the room effect, and the beginning of the presence of the reverberant field in said room, the index m corresponding to a number of blocks of samples of a duration corresponding to this delay, M being the total number of blocks that a transfer function lasts in a time-frequency representation, the symbol “.” designating multiplication, the term “*[0;. .. ; f k (l)]” designating the convolution operator on a limited number of frequencies and ranging from a lowest frequency to a maximum frequency f k (l) which is a function of at least the input signal of index l, and the term “*[0;. .. ; f k (m)]” designating the convolution operator on a limited number of frequencies and ranging from a lowest frequency to a frequency f k (m) which is a function of the block of samples of index m.