Accurate frequency reproduction makes it possible to evaluate the quality of the vocal performance.
That's why a professional voice-over recording studio like Lisa Jayne’s will use Studio Monitors to play back "uncolored" audio.
Lisa Jayne uses BLOW5D Near Field Studio Monitors from SIMS Audio, a global audio equipment manufacturer that is a well-kept secret here in the US.
Lisa Jayne's BLOW5D monitors offer high output (90 Watts of power) with a flat frequency response (±1.5 dB, 58 Hz to 20 kHz) and wide pass-band frequency (50Hz ~ 22kHz). They excel at pure frequency reproduction.
All this makes for professional voice-overs that are carefully evaluated with frequency-accurate playback.