It seems like every year Opera News has an article or an editorial on opera singers singing "popular" music. The current issue has one such article, by Matthew Gurewitsch, plus an editorial that makes the usual points: why shouldn't opera singers cross over, why are you all such snobs, wasn't Eileen Farrell great.
The thing I don't usually see addressed in these articles and editorials is the fact that there's another type of "crossover" singing besides the one that Gurewitsch writes about. He's mostly writing about opera singers who sing popular music or record a few show tunes. But there's also a longish history of opera and classical singers actually performing in full-fledged forms of popular entertainment, especially Broadway musicals.
If you listen to a Broadway cast album from the '50s, one thing you might notice is how many trained voices there are – not "musical theatre" trained, but classically trained, with baritone, tenor and soprano voices that were produced just like operatic voices. Most Broadway shows before the '60s did not have microphones; singers were expected to project to the whole theatre. That's why Broadway orchestrators tended to thin out the orchestration when people were singing, and use the brass only to punctuate the sung lines: there was no amplification, so it was essential to make sure that the singers weren't drowned out by the orchestra. Many Broadway shows included singers who also performed in operas and oratorios, singers such as the New York City Opera's John Reardon (who introduced "Make Someone Happy" in DO RE MI), Patricia Neway, the original Magda Sorel in Menotti's THE CONSUL (and the Mother Abbess in the original production of THE SOUND OF MUSIC), and Carol Brice, possessor of a great contralto voice, who recorded El Amor Brujo with Fritz Reiner but is probably best known for her roles in musicals like The Grass Harp (where she introduced one of that show's many cult-classic songs, "If There's Love Enough"). Fifty years ago, the term "crossover" was almost irrelevant: if you were a singing actor working in New York, you went where the work was. It was considered "crossing over" if an operatic star, like Ezio Pinza, did a Broadway show. But there have never been all that many stars in the opera world; mostly there are singers, and in Broadway's Golden Age (tm), Broadway shows tended to need a lot of good, trained, "legit" singers.
As it happens, The Grass Harp in 1971 spelled the end of that kind of singing in Broadway theatres, because it was the last show with no microphones. Amplification eliminates the need for voices that can project on their own, and, indeed, a voice like Brice's would probably not come off well through a modern theatre sound system. It's only fairly recently that "musical-theatre" has become a style of singing in and of itself, requiring specialized training. But I would say that the style of good classical singing is more suited to the great musical theatre songs than the whiny, microphone-centric singing that today's musical-theatre training encourages. I never took a course in musical-theatre singing, but I used to go to shows given by people who did. A singing teacher would sit at the piano while her pupils came out on stage and demonstrated their voices in numbers from the "HACKNEYED BROADWAY SONGS EVEN YOUR KIDS WILL HAVE HEARD OF" songbook. I admired said voices, and their ability to get through the lyrics of "I Enjoy Being a Girl" without embarrassment. What I didn't like was the stuff that their teachers had told them to do. These young women, who were obviously capable of singing full-out, would instead sing in a kind of ear-piercing head voice that had little to do with the kind of voices that these songs were written for; a Richard Rodgers or Cole Porter would usually be writing for a legit soprano, or an impossible-to-categorize singer like Ethel Merman, but not singers who sang in a tone that gave you the feeling that, if they went any higher, only dogs would be able to hear them. (Please note that I'm not knocking the students I heard; just the way they had been trained to sing.)
If you want to worry about what's happened to musical theatre singing in the last 50 years (and who doesn't enjoy worrying?), listen to the "Conversation Piece" number from WONDERFUL TOWN. At the climax of the number, composer Leonard Bernstein writes a little coloratura obbligato for the character of Eileen, a funny bit of operatic spoofery that looks forward to "Glitter and Be Gay" in CANDIDE. On the original cast recording, Edie Adams -- a classically trained singer, though she didn't always let on -- handles the coloratura with ease; Jacquelyn McKeever on the TV cast recording (from 1958) has more trouble with it, but gets through it all right. Recent Eileens tend to have serious trouble with this bit, kind of faking their way through it and requiring a slow tempo even to do that much (case in point: Rebecca Luker on the 1998 two-disc studio recording on the JAY label). Broadway musicals need good legit singers, but there are getting to be fewer and fewer who can do it, because the art of musical-theatre singing often seems to be thought of as something separate from classical singing, instead of an extention of it.
This is one reason why I've never understood the praise for Eileen Farrell's "popular" singing. Farrell had a wonderful soprano voice. So what does she do when she sings Cole Porter? She does her damndest to disguise her wonderful soprano voice, instead using a chesty, piercing voice that makes her sound like just another pop singer with a larger-than-usual voice. When I hear Farrell singing "In the Still of the Night" as though she were a louder, heavier Margaret Whiting, I wish she'd just cut it out and be herself -- especially since Porter wrote "In the Still of the Night" for a legit singing voice, that of Nelson Eddy. This is, to an extent, my complaint about a lot of opera singers who sing "crossover," that they feel a need to try and be jazzy and cool and all the other things that have little to do with a Rodgers and Hammerstein song. Of course, if an opera singer decides to just be himself or herself in singing musical-comedy songs, that's no guarantee of a good rendition -- but that's in part because he or she may simply display the same flaws as in his or her operatic work. Thomas Hampson, on his various EMI recordings of show music, is rather stiff and mannered -- but those problems are there in a lot of his operatic and art-song singing, too.
I don't really have a good conclusion for this post, so I'll close instead with my favorite anecdote about the legit singing style on Broadway: for the musical The Pajama Game, the producers hired a young pop songwriting team, Richard Adler and Jerry Ross, with no Broadway experience. Deciding that leading man John Raitt (not precisely an operatic singer, but certainly a "legit" Broadway singer) was too square, they tried to teach him to sing their songs off the beat, pull the tempo around, depart from the written notes, just the way pop singers do. Raitt told the songwriters he wouldn't sing off the beat, that Richard Rodgers had taught him that a theatre song works better if you sing it "straight." I would have to agree.