Complex sentence: Notwithstanding the imperfection of recording one can tell that the voice of Peter Slovtzov was naturally rich and attractive, of mellow timbre, clear and unique in its strength yet velvet sounding.
Split into simpler sentences: Notwithstanding the imperfection of recording one can certanly be sure, that the voice of Peter Slovtzov was naturally rich and charming. The voice of the singer was of mellow timbre, clear and exclusive in its strength with velvet sounding.