A larger voice will of course be heard as a larger voice if it has Singer’s Formant. If it doesn’t have Singer’s Formant it would not be easily heard over a full orchestra regardless of how large a voice it is. Intensity or volume of production has little to do with the ability to be heard over an orchestras.
All male singers produce fundamentals that are mostly within the loudest sounds of the orchestra which extends up to about the 500 KZ range. So, by definition their fundamentals are covered over by the orchestra, They are heard only because, and if, they are able to produce some sonic emphasis in the regions in which the orchestra is weaker and that is in the range of the Singer’ Formant. As listeners we are not aware of all of this but our ears send messages to our brain that correlates the Singer’s Formant to a fundamental and it translates that message such that we hear a loud fundamental as well as lower overtones and recognize not only the pitch but even the vocal quality. It is a wonder of how our minds make reality for us.
It is totally logical to expect that a louder voice will be heard more easily over the broad spectrum of orchestral sound but this is a case in which common sense logic fails us. Do not confuse the overall color or depth of a voice with its ability to be heard; it is primarily only the Singer’s Formant that gives the voice its ability to be heard and via that resonance frequency is able to present itself with all of its qualities.
This kind of implausible sonic logic also occurs in instrumental music. A faculty cellist once showed me that the cello’s lowest note on its open longest string has so little fundamental present that it could almost not be heard were it not for its overtones. He played that note (C2), recorded it and filtered out all of the overtones of that pitch. The result was a barely audible fundamental. His point was that if the cello part is not well written by the composer, the cello can be easily overpowered by the orchestral sound because the cello does not have a boost of tone in the 2800-3200 Hz range. The voice does. In short, it makes no difference how heavy or loud the instrumentation of the orchestra; their sonic emphasis is only at the 500 Hz range and their sonic intensity at 2500-3600 is extremely weak by comparison.