Last week, I saw two classic Broadway musicals in seven days: “Annie Get Your Gun” at Glimmerglass, which I wrote about in my recent article about that festival, and Oklahoma! at the Arena Stage in Washington, which I finally saw on Saturday night.

Opera companies all over the country are putting new emphasis on presenting classic musicals in the original orchestration, without amplification: the Chicago Lyric Opera, Glimmerglass, and probably the Washington National Opera in the future. In theory, I’m all for it. Amplification has raised the decibel level of the Broadway experience and done some sad things to the vocal technique of many Broadway singers, who croon rather than projecting. At the Arena Stage, “Oklahoma!” opened with Curly singing the first phrase of “Oh What A Beautiful Morning” offstage, and then the amplification ramped up when he made his entrance, and I felt the palpable sense of disappointment of a burst bubble; something of the initial magic was lost.

Yet as I said in my earlier article, the singing in “Annie Get Your Gun,” though unamplified, was not particularly exciting either. Indeed, Deborah Voigt and Rod Gilfrey gave the impression of being less invested in, or less serious about, this musical than about opera, as if carelessness were a hallmark of the “lightness” of this particular style. At two different junctures, Voigt let loose with a full-throttle operatic high note, and in each case it was as a kind of punchline — “See? This is what I can really do.” Rather than being funny, the moment became frustrating: if you can sing that well and that loudly, why does the rest of your singing seem so pale?

Voigt might answer, reasonably, that the music wasn’t in the best range for her. Much was made of the fact that “Annie Get Your Gun” was being presented in the original orchestrations, in the original key, but I’d counter that if you want to observe this kind of authenticity you might want to cast someone in the lead role who had the vocal range the music was written for -- whose voice is trained to boom out in that lower register like Ethel Merman, the first Annie. I personally think that as a dramatic soprano, Voigt really ought to have a more solid lower voice, but since she doesn’t, why not shift the music to a range where it would suit her better?

Here we have a pitfall of what I’ll call the opera-izing of the American musical: fetishizing authenticity is of questionable value when it comes to the Broadway tradition. Unlike opera, most musical scores aren’t actually written by the composer; the outlines are fleshed out by a professional orchestrator. Yes, what we heard at Glimmerglass was the version of the score that Irving Berlin sanctioned; but wouldn’t Berlin have sanctioned other versions if they had been better suited to other performance conditions? Binding a production to this kind of authenticity becomes a form of straitjacketing -- and may even allow directors to punt on their dramatic responsibility. “Annie,” at Glimmerglass, was treated very much like too many American companies treat opera: present it as originally written, don’t do much to it dramatically, keep it in a glass case to give patrons the “authentic” experience. (Zambello’s sterile, kid-gloves approach to “Annie” was a far cry from the deep-digging dramatic exploration she undertook of Wagner’s Ring.)

The Arena Stage’s “Oklahoma!” couldn’t have been more different. The energy crackled on stage right from the start, as an excellent cast worked with all their hearts to bring to life an idealized vision of a past America, a multicultural home on the range. (E. Faye Butler did such an outstanding job as Aunt Eller that I was and will remain convinced the character was always meant to be African-American; and casting Ado Annie as a real-life high-schooler, June Schreiner, was an inspired idea that stripped the schtick from the character and made her simply adorable.) If the book was dated, the cast didn’t know it; the audience was laughing as freshly at the 70-year-old lines as if the jokes were new.

Yes, the original orchestration was reduced to a chamber ensemble of only 12 instruments. But the arrangements, many of them reworked by the show’s music director and conductor George Fulginiti-Shakar, were outstanding. They incorporated local color (banjo, harmonica), worked in some new dance numbers, and helped revitalize the whole experience. Don’t get me wrong; I’m thrilled when I get a chance to hear a full-size orchestra in a Broadway show. But I’d rather hear a thoughtful reorchestration that actively enhances a production than a dutiful performance that merely goes through the motions. (And since I mentioned dance: Parker Esse’s energetic, even hyperactive choreography gave “Oklahoma!” a teenage, even “Rent” vibe. Glimmerglass, alas, didn’t have the resources to mount the dance numbers as more than seat-of-the-pants approximations.)

Of course, “Oklahoma!” is a better piece than “Annie Get Your Gun.” It suffers from a long-standing affliction of musical comedies from Rossini’s day on, a weak second act, and it could use some dramaturgical rearranging, but it’s still more naive, more solid, more moving than “Annie,” which has a deliberately tongue-in-cheek flavor. Part of the difference between the two works comes from the way musicals used to be tailored to their casts: “Oklahoma!” was written for young unknowns, “Annie Get Your Gun!” was written for Ethel Merman. Operas, too, were originally tailored to specific singers, and reworked when other singers came into the mix; of course, we don’t take such liberties today, but there is an attempt made to cast roles with singers who are suited to them. (The degree to which this is or isn’t done is a steady topic of debate in opera chat rooms.)

It may be heretical to say it, but I came away from seeing these two productions feeling that, for all my love of unfiltered sound and big orchestras, there are more important things than authenticity. Indeed, I’m concerned that in staking out Broadway territory, opera houses might coast on their presumed superiority, offering authentic but lukewarm productions that lack the sparkle and pizzazz of commercial theater. I love this tradition, but I’d hate to see it sanitized, in the name of protecting it, to a point where its natural audience appeal is eradicated. If I’m forced to choose between miking and theatrical efficacy, the show I actually enjoyed is the one that’s going to win out.