Dr. Henry M. Truby of the University of Miami used samples from three Beatles songs sung by Paul McCartney (Yesterday, Penny Lane, and Hey Jude) and produced three very different sonagrams.Reeve, Andru J., Turn Me On, Dead Man: The Complete Story of the Paul McCartney Death Hoax, Ann Arbor: Popular Culture, Ink, 1994: 69.
[T]he term "record" means any item, collection, or grouping of information about an individual that is maintained by an agency, including, but not limited to, ... other identifying particular assigned to the individual, such as a ... voice print ...... (B) unique biometric data, such as ... voice print ...; ...[T]he district court found that duty titles were not comparable to captured immutable characteristics such as finger or voice prints or photographs. The district court reached these conclusions because an individual's duty title changes over time, because multiple people can concomitantly have the same or similar duty titles, and because each individual has predecessor and successor holders of the same duty titles. We agree with the reasoning and conclusions of the district court. In circumstances where duty titles pertain to one and only one individual, such as the examples of identifying particulars provided in the statutory text (finger or voice print or photograph), duty titles may indeed be "identifying particulars" as that term is used in the definition of "record" in the Privacy Act. For the reasons detailed by the district court, however, the [**9] duty titles in this [*188] case are not "identifying particulars" because they do not pertain to one and only one individual.
If you focus in on the voices, obvious differences are detectable.
It seems the studio magiCIAns might have used something called "audio stretching" to make Faul's voice sound more like Paul's. This is from "Sgt. Pepper":
The only real version of Sgt. Pepper is the mono version," says former Beatles sound engineer Richard Lush. "There are all sorts of things on the mono, little effects here and there, which the stereo didn't have."
Because stereo wasn't as commonplace in the 60's, the mono mixes were always given top priority. That meant in this case the mono mixing was done with much love and care, with the Beatles in attendance, whereas the stereo mixes were made in just a few hours afterwards by Producer George Martin alone. Of course, stereo was soon to take over and this meant that this original mono mix with all its subtle differences (like, for example, She's Leaving Home played at the right speed rather than slowed down as it is on the stereo) was soon deleted...
The Beatles - Sgt. Pepper's Monomix
Here is an example of studio magic being used on "Strawberry Fields Forever" to change how the voice sounded: