I think what makes Crowe's voice a bit jarring is it sounds kind of unnatural. What I mean is it sounds as if he is consciously (or maybe subconsciously) trying to deepen his voice. The result comes off as amateurish.
I will say that, even so, I'm not all that disappointed based on what I've heard of him so far. It's one of those things that I'm sure I'll get used to enough that it won't bother me half way through the film.
But, as is usually the case with me, my mind is relentlessly detail obsessed and nit picky, so of course I've got a theory, hehehe.
And the following is just that, a subjective theory. I am in no way claiming it is a fact.
Why might he be deepening his voice? The same reason all those American Idol rejects embarrassingly have the tendency to imitate the original artists of their chosen song, but they imitate them badly, of course, and with emphasis on only the few characteristics that are more a unique part of the original singer rather than characteristics of an artistic interpretation. This is usually done subconsciously (like 99.9% of Idol rejects), and it happens when a mind can't refer to any natural, inherent talents. Of course, if one is determined to be a star, they cling onto any recourse available and thus the mind assumes if they can sound as much like the original artist as possible, then that = a GREAT singer, because, hey, you sound just like someone famous!! Never mind whether or not that famous person really possesses a spectacular singing voice, just emulating a person who happens to be famous is enough. When a no-talent decides to compete in a singing competition, they are going on purely what they hear through their heads and if it matches in some way to a famous singer, that must mean they are gifted singers. Case in point:
https://youtu.be/6ijx-oe0o64?t=40s Dude honestly thought he was awesome because his mind had tricked him into believing just that. He actually successfully emulates some of Madonna's unique inflection, but that's not interpretation, it's Madonna! So copying her is trying to sound like a woman, a woman with a very high pitched voice, and it's trying to be someone you're not, lol. Throw in no talent and you've got a BAD imitation, a caricature of Madonna.
An artist interprets and creates. Emulating and attempting to carbon copy is the mark of an amateur. Unless, of course, you are an impersonator and have talent and thus are good at impersonating. Imitation, reproduction, and impersonation are certainly valid artistically as well, but what distinguishes them from what an amateur does is one's inherent good taste and natural talent regulates all those fine details and turns in a winning performance. An amateur approaches it without any intention of copying consciously, they sincerely think that reproducing only one or two distinct traits of a famous singer means they've arrived and they are GREAT.
So if a performance feels iffy (emphasis on "feels" because it can technically sound good, be on key, and not have obvious flaws but can also still have a jarring quality to it) it's more often than not due to misguidedness on the part of the singer.
Now, I'd never be so mean as to place Crowe in that category and he certainly has many diverse talents that he applies effectively to his craft, but he might be guilty of either intentionally or unintentionally morphing his voice in a way he perceives a Javert should sound like, based on the many men who have played him onstage. To his credit, it isn't over-the-top or ridiculous but I get the distinct impression one gets when witnessing a singer trying to be an *idea* of a singer and character rather than an artist crafting an interpretation of a character.
I probably typed all of this for nothing because I realized before even typing it that it's certainly possible Crowe's singing voice simply has that quality--a quality that comes across as what I wrote above, but isn't actually borne out of that and is inherent. I've never heard the man sing before and knew I could be very wrong. But I decided to type this without even first checking some of his earlier singing work, because the point isn't that I think I'm right or want to be right. Nor did I post this to school anyone on anything.
I'm a fan and this is the kind of sh*t fans do! LOL. I just turn it up a few hundred notches...thanks to my uber nit-pickiness, roflmao. People always assume I go through all this trouble. Trouble? I produce this crap in minutes. Not like I sit here half the day writing stuff about amateurs, ha! I do this and don't even post it sometimes, and just save it for myself.
And the length helps weed out those who can't care less about the things I care about, which is always a nifty bonus.
Recreation of original John Cameron orchestration to "On My Own" by yours truly. Click player below to hear.