A filtering determination method for determining filtering combinations of a spatial processing operation, the filtering combinations being determined as follows: c l, m l ′, m ′ f = ∑ l " = 0 L ∑ m " = − l l " c l, m, l ", m " l ′, m ′ G l ", m " f where I and m respectively denote the order and the term of the coefficients of the initial representation, l', m' denote the order and the term of the coefficients of the modified representation and, I", m" denote the order and the term of the coefficients of the directivity function, the filtering combinations C l, m l ′, m ′ being intended to be applied to an initial sound field representation (P (l) l,m) formed by coefficients representative of the initial sound field in time and in the three spatial dimensions, where the Fourier-Bessel coefficients P l,m ( f) of the initial sound field correspond to the spherical harmonic coefficients of a directivity function P ( θ,φ,f), in order to provide a modified sound field representation (P l,m) formed by coefficients representative of the modified sound field in time and in the three spatial dimensions, where P l,m ( f) is a modified representation corresponding to a modified sound field, by applying to it the processing filtres representative of the at least spatial processing operation defined by the application of the frequency response processing filtres F l, m l ′, m ′ f in the following manner: P l ′, m ′ T f = ∑ l = 0 L ∑ m = − l I F l, m l ′, m ′ f P l, m I f where P l,m ( f) is the Fourier transform of P l,m ( t) and where P l,m ( f) is the Fourier transform of p l,m ( t), the coefficients relating to the initial representation and respectively to the modified representation, the method being implemented by a determination device and characterised in that it includes: - a processing definition step of defining the processing operation by a set of at least one directivity function, each directivity function associating with each direction of space a real value or a complex value; - a coefficient establishment step for establishing the spherical harmonic coefficients for each directivity function; and - a filtering determination step for determining the filtering combinations from the spherical harmonic coefficients; in that the processing operation is defined by a directivity function and a predetermined operation intended to be applied on: - the initial sound field represented as a directivity function; and - the directivity function of the processing operation; the method in addition including: - a coefficient determination step for determining the weighting coefficients (c) associated with the predetermined operation, in which the step of determining the filtering combinations comprises a step of determining each filtering combination from a linear combination of the spherical harmonic coefficients with the weighting coefficients (c); and in that the coefficients representative of the initial sound field and the coefficients representative of the modified sound field are Fourier Bessel coefficients; and in that it further comprises a parameter specification step of specifying a parameter representing the order limit of the Fourier-Bessel coefficients. - a processing definition step of defining the processing operation by a set of at least one directivity function, each directivity function associating with each direction of space a real value or a complex value; - a coefficient establishment step for establishing the spherical harmonic coefficients for each directivity function; and - a filtering determination step for determining the filtering combinations from the spherical harmonic coefficients; - the initial sound field represented as a directivity function; and - the directivity function of the processing operation; - a coefficient determination step for determining the weighting coefficients (c) associated with the predetermined operation, in which the step of determining the filtering combinations comprises a step of determining each filtering combination from a linear combination of the spherical harmonic coefficients with the weighting coefficients (c); and