A general transport theory of the electronic contribution to the acoustic attenuation and amplification in nondegenerate semiconductors is presented. External electric and magnetic fields are applied parallel to the acoustic wavevector. The piezoelectric and the deformation potential coupling mechanisms have been taken into account together with self‐consistent electromagnetic fields. The classical theory predicts that there is no dependence of the attenuation on longitudinal magnetic field. A numerical example has been fully developed and the results are compared with the approximations for low (ql<1) and high (ql>1) frequencies. The values of both the frequency and amplification coefficient for the frequency of maximum amplification are found to be larger in the exact theory than those found by extrapolation of theql<1 approximation.