.mp3 and .m4a files below 25Mb are permitted. (iPhone voice memos record to .m4a)
Online Convert is a good place to convert your files online if you are not familiar with Audacity
40.740119, -73.967926
40°44'24.4"N 73°58'04.5"E
We also accept what3words addresses
Audio files should be longer than 1 minute and shorter than 10. Field recordings and voice memos of all kinds are great