Recently, I came across the need to reference a chart of musical notes and their frequencies, for the purpose of calculating the wavelengths of certain notes, and realized there wasn’t a great tool out there to do this automatically. So, I created a multi-dimensional PHP array so that I could access this data, loop through it, and make whatever calculations I needed to.
Below is the resulting Gist, and it is available to use freely in your own projects.
I used this PHP array to generate a handy reference table of musical frequencies and wavelengths, available here.
More info about the topic of Musical Frequencies at this Wikipedia entry.