Many thanks to Laura Books-Rice for clueing me into this excellent video of Giacomo Lauri-Volpi giving a voice lesson back in the day when recordings were a new and miraculous thing. Of particular note to this listener is the unforced quality that Lauri-Volpi exhibits. The great tenor mentions three things as being necessary in singing: voice, ear and soul. How often do you hear this last word in the voice or rehearsal studio? He also mentions that - as a tenor - he does not sing F# uncovered. How to do what he means? That takes one back to his second requirement: ear.
Those seeking a deeper knowledge of Lauri-Volpe's thoughts on singing will want to find his 1955 treatise titled Voci Parallele (Parallel Voices), while an excellent post on Lauri-Volpe's life and career can be found at Opera Gems.
Photo by Herman Mishkin.