I was taken aback by his soft, lilting voice. That isn't how he's supposed to sound, I thought. That isn't how this poem is supposed to sound.
How should a poem sound? The written word is a funny thing. Some people experience it visually. Others experience it audibly. Some experience both simultaneously. Is our audible experience of a poem as valid as the poet's intended phrasing?
Poet Sara Holbrook wrote about why she will not explain her intended meaning of a poem to students. Once a poem is released into the wild, the right of interpretation passes to the reader. Inflicting a single "correct" interpretation of the meaning on all readers is to take away the experience of discovering the resonances and relatability of the poem for the individual reader.
So too with the sound of the poem. What rhythm the poet intended to be present in the poem should be encoded into the poem itself, waiting for the reader to discover it. Finding out that the poet had read the poem completely differently than the reader has been hearing it can be a bit of a shock - but it is one that should not detract from the experience of the poem, nor does it invalidate the reader's interpretation.
Here, for example, is T.S. Eliot reading The Waste Land," a poem many encountered in high school. Does this differ from how you had heard it in you head?
There is a video with a clip of William Butler Yeats reading "The Second Coming," but it makes use of a visual gimmick so bizarre and disturbing I will not include it here. Surprisingly, his recitation is very close to how I imagined the poem to sound the first time I read it.
Here is another recording of Yeats where he tells an anecdote about another poet's reaction to hearing his own poetry read by someone else. He also recites several of his own poems, as he intended them to be heard.
There is value in hearing poems read in the poet's own voice. I have books that contain poems that I have heard read aloud by their authors, and it is fun to read them in the voices of the poets who wrote them. But the voice in which you hear the poem as you read it is just as valid. Perhaps more so. The poem as read by the poet involves just the poet and the words. But the poem as you hear it involves an interaction between poet, the poem, and the reader.