According studies conducted well before the release of Bohemian Rhapsody, Mercury was the one true all-time great, and they’ve got the acoustic research to prove it.
Czech and Swedish voice researchers Christian T. Herbst Stellan Hertegard, Daniel Zangger-Borch and Per-Åke Lindestad did an acoustical analysis of Mercury’s voice and found that his vibrato was truly different from those of classically-trained (opera) singers, reports Maxim.
First a quick explanation: the word “vibrato” as it relates to the human voice is one of those terms that gets thrown around a lot and no one knows how to explain it. Vibrato is simple, though—it’s just the steady pulse of the voice above and below the tone, and it’s produced by a natural muscle reaction to air flowing through the throat.
According to the researchers, opera singers make their tones “more vibrant” and that vibrato sits at around 5.5 to 5.6 Hz. But Mercury’s vibrato was higher frequency—about 7.0 Hz, and had a signature irregularity—a kind of “vocal fingerprint” that could only be from Freddie Mercury.