from C4 , my voice lost in timbre. I had a lot of answers on many singing forum. but nothing that really helped me I tried different vocalizations that have suggested me , the mouth (after I know the Latin etymology of the word..."ebouchure") , with a mirror. I have always been no clarification after taking singing lessons for several years TCM , SLS ( seth riggs methods ) I posted a song from someone who sings superbly well , pretty voice , but being a paid forum, did not wish to enroll in contrast technically , his singing is very good. it goes into falsetto at fa3 (G4) and being more comfortable than me in the treble, trying to get the classes mixed voice. without success I begin to wonder if it is not innate and if the ability to reach high notes in full voice are not already acquired by the configuration of the vocal cords .... the tessitura of the voice good continuation and good singing