Sound waves require a medium for propagation.
The Doppler formula for frequency shift differs slightly in two situations
(i) Source at rest, observer moving υ′ = υ [

v±v0

v

]
(ii) Observer at rest, source moving υ′ = υ [

v

v±v0

]
The two formulas are different because motion of the observer relative to the medium is different in the two situations for light waves in vacuum.
No such relative relation of observer and medium exist.
Hence only the relative motion between the source and the observer counts and the frequency shift is same , υ′ = υ [1±

v

c

]