We can, however, look at his career milestones:
* Early roles (1999-2001): In his early roles, like "David Copperfield" and "The Tailor of Panama," Radcliffe's voice still had a noticeable childlike quality.
* "Harry Potter and the Sorcerer's Stone" (2001): At age 11, Radcliffe's voice was already showing signs of deepening, but it still had a relatively high pitch.
* Later "Harry Potter" films (2002-2011): Throughout the series, Radcliffe's voice noticeably deepened, especially during his teen years.
* Post "Harry Potter" (2012-present): By his late teens, Radcliffe's voice had fully matured and settled into its current, lower register.
Therefore, we can say that Daniel Radcliffe's voice deepened gradually during his teenage years, between the ages of 12 and 18, coinciding with his time filming the "Harry Potter" series.