When I purchased my D-30R's I had a chance to listen to the D-20R. Given how similar they look, they do sound quite a bit different. The D-20R is slightly darker speaker with a full rich sound. They imaging was top notch and the sound was very seductive. Bass was a bit soft and maybe not as precise but overall it was impressive.
The D-30R is more like its big brother the D-48R. More neutral and detailed with better dynamics. All things being equal and depending on your budget the D-30R might be the better choice.
The D-30R is more like its big brother the D-48R. More neutral and detailed with better dynamics. All things being equal and depending on your budget the D-30R might be the better choice.