Last Thursday night, I attended the first concert of the Waco Symphony Orchestra’s new season. It was a fine performance in which the orchestra played pieces by Russian composers Sergei Prokofiev and Pyotr Tchaikovsky, in addition to opening the show with a Brazilian piece. The Prokofiev piece was an orchestral suite of music from his ballet “Romeo and Juliet,” and the Tchaikovsky was his Violin Concerto in D performed by the WSO’s guest artist, Serbian-born violinist Andrej Kurti

As I listened to Kurti play the piece with unquestionable brilliance, I reflected on why it is that I often find myself reacting very differently to some solo concertos. I should say up front that I like Tchaikovsky. I think a lot of his ballet music is some of the catchiest even written. A lot of people agree — he’s unquestionably popular and not just during Nutcracker season. His name up on the marquee is a good way to get people into the hall. Neville Garden, in a useful little book titled “Good Music Guide,” says audiences flock to Tchaikovsky concerts simply because “he wrote wonderful, heart-filling, emotional melodies and was a master of brilliant, luxurious orchestration.”

Russian composers like Tchaikovsky and several of his contemporaries have such melodic power chiefly because they were deeply rooted in the culture of Russian folk music. As Tchaikovsky himself explained it, he was “saturated from earliest childhood with the miraculous beauty of Russian popular song,” and this in part accounts for the stirring melodic content in so much of his work.

On the other hand, I often get a very different feeling from his concertos, and this struck me particularly hard Thursday. To be sure, these pieces can contain some great melodic lines (just think of the first part of his famous Piano Concerto No. 1), but just as dependably they descend into what strikes me as a comparatively arid showcase of unrelenting technical virtuosity (think of the rest of the Piano Concerto No. 1).

In a way, that’s sort of the point of the solo concerto. There’s something emphatically romantic about its very form: an individual performer standing against the whole assembled power of an orchestra, persevering against the odds through his or her technical mastery of a single instrument. It’s the musical equivalent of Audie Murphy standing atop a tank holding off an entire German battalion. It is, in short, heroic.

Feeling bad for my reaction, the first thing I did the next morning when I got into the office was put on a CD of Tchaikovsky’s Sixth Symphony, one of the most emotionally loaded pieces of music ever. (The composer himself conducted its November 1893 premiere in St. Petersburg, and nine days later he was dead. Soon people were listening to the somber symphony as being some kind of suicide message as theories quickly cropped up about the real cause of his death.) I wanted to hear the kind of unforgettable melody for which he was famous, and I found it.

What this points to is a subtlety that’s key to appreciating the variety of what we tend generically to call “classical” music. Despite what may seem a superficial similarity between pieces of music, there are different purposes at play. Being aware of these varying purposes helps make sense of what we’re hearing. Some works are composed to accompany ballet. Others are intended to highlight the technical ability of a soloist. Others are meant to evoke particular emotional responses, from celebration to mourning. Keeping this in mind makes the rich variety of orchestral music much easier to understand.