Vegetal wools present interesting acoustic insulation and absorption properties and are now identified as key solutions to promote green buildings. However, their fibres size distributions are spread and variable. So, in order to optimize the acoustic performances of vegetal wools, it is necessary to take into account these microstructural characteristics by using a model based on a micro-macro homogenization approach. Thus, an approach based on a mix between Homogenization of Periodic Media (HPM) and Self-Consistent Method (SCM) with cylindrical geometry is developed to model the intrinsic parameters and the sound absorption coefficient of vegetal wools. The specificity of this Self-Consistent approach is based on the energy equivalence between a generic cylindrical inclusion, representative of the vegetal wools physical and geometrical properties at microscopic scale, and the homogeneous equivalent medium at the macroscopic scale. Future investigations will aim at extending this method at the thermal properties modeling in order to develop an acoustic and thermal joint approach for vegetal wools.