What you are training
A vocal has four bands that decide whether it sits forward or sinks: low mud around 200 to 300 Hz, honk around 800 Hz, presence around 3 to 5 kHz, and air above 10 kHz. Most vocal EQ decisions live in those four places, and most amateur vocal mixes are wrong in one of them: too much mud from a close mic, or a presence boost that turned sibilance into pain. This drill applies a boost or a cut to a real vocal phrase and asks you to name the band. Because the source is a voice rather than noise, you learn what each band sounds like on the instrument you will actually EQ, which transfers to the session in a way that noise-only ear training does not. Expect the 800 Hz and 3 kHz rounds to be the ones that separate a trained ear from a guess.
After this drill, the plan: The daily plan starts you on vocal mud and presence, the two bands behind almost every "my vocal sounds amateur" complaint, then adds air and honk.