EXCLUSIVE

Elizabeth Holmes ﻿is being outed as a fraud of epic proportions in the business world, but there's nothing deceitful about her curiously low voice ... so says her family.

Elizabeth, the disgraced Silicon Valley hotshot, is the subject of a new HBO documentary chronicling the meteoric rise and spectacular fall of her company, Theranos ... all the result of Elizabeth falsely claiming she discovered a way to revolutionize blood testing.

Elizabeth wowed world titans like Bill Clinton, George Schultz and Henry Kissinger, partly with her intoxicating pipes. But, a Stanford professor featured on the doc and others say even Elizabeth's voice was BS ... they say she faked it. Viewers of the doc made "voice" the buzzword for fraud.

Her family, however, is calling BS on the doubters.

Elizabeth's family members tell us her voice is naturally low. We're told most people in the fam have low voices, including her grandmother, and Elizabeth will occasionally change her pitch to a higher octave -- especially when she gets excited or passionate.

As for Elizabeth's fraudulent business practice ... her family tells us they're standing behind her and remaining supportive.

Her company went from being valued at more than $9 billion to below zero. She's also been indicted for allegedly defrauding investors out of hundreds of millions of dollars and deceiving hundreds of patients and doctors with the bogus blood test. She's pled not guilty.