No reason other than at the time 256 loaded sound samples was plenty. Have you every had more than 256 samples loaded into memory for any game you've made? So far I've not so this seemed like a good upper limit. Loaded samples are one thing, but dynamic playing buffers are another. You want to keep those to a reasonable amount for performance sake. At first I had them set to 256 as well. Having up to 32 sound buffers all playing at the same time, is/was plenty. You can however set what ever values that you need for you project. For me those were good numbers that worked well over the years. I never got around removing the hard limits because the need never came up.