I was able to disable the bells (both auditory and visual) in MacVim simply by adding "set vb" to ~/.gvimrc. The visual bell doesn't work for me in MacVim. Not having a visual bell was my desired outcome, but this isn't a very straightforward way to get it. This works for now, but I would like to know of a more legitimate way to disable both the auditory and visual bells, in case the visual bell starts working in MacVim in the future.

Further reading

• Vim wiki: "Disable beeping and flashing"
• Vim wiki: "Disable beeping"
• Learning the vi Editor