Having heard hundreds of students preach in my various classes, I’ve discovered that there is a limit to a person’s “dynamic range.” Like a musician that can sing over multiple octaves, some preachers are capable of hitting the high notes as well as the low notes, speaking loudly and confidently at one point of the sermon and softly and sensitively at another. Others, however, bring a narrower range. Their highs are not as high and their lows not quite so low.
Ideally, I would want all of my students to be able to expand their range. Professional singers always work to broaden the range of their voices and their emotional capacities. Preachers ought to also.
However, it seems obvious that there is a limit to what any of us are going to be able to reach. We are all limited by our personalities. Some of my students are soft-spoken by nature and will never be able to reach the boisterous levels achieved by some of the other more extroverted students.
This is not to say that a limited range necessarily makes for poorer preaching. I would suggest, however, that each of us ought to be working to explore the outer edges of our range. We need to vary our emotional tone. The changes can be subtle, but listeners need to sense some modulation in our voice and in our emotional intensity.
However wide your range, you ought to explore every note of it.