Please do your best to submit lossless files, that is, WAV, AIFF or FLAC format.
If you are not 100% positive that your tracks are 100% FCC-clean, please contact me at firstname.lastname@example.org BEFORE submittal. Let’s not risk removal of me as a host because of carelessness or cluelessness, okay? Please review this reference.
Here’s another excellent reference for good practice: PRX Guidelines
These are the only filetypes that are CD quality. MP3 and M4a are lossy, and even the highest bit rate conversion doesn’t overcome this. Please don’t convert a lossy file to a lossless format. An inferior file can’t be made better after the fact, the same way an enlarged cellphone photo can’t be made less grainy by taking a photo of the cellphone photo with an expensive DSLR.
When I’m developing a show playlist, I limit lossy files to 5 of the 35 tracks. By sending MP3s and similar, you limit your chance to be heard. There are more of us in the broadcast industry than you may realize. My longest-tenure station, for example, asks us hosts to avoid lossy files, and they are very reluctant to load these files onto the server for widespread use across shows.
Sometimes artists only have MP3s on hand, maybe because the recording engineer only provided them, and maybe because the artist didn’t ask for the lossless files. Just go back and ask the engineer.
Because WAVs, AIFFs and FLACs can be large, emailing is often not feasible. Many artists and labels use Dropbox, Google Drive or equivalent to deliver files. In either case, please direct files to email@example.com. If needed, I can provide you an upload folder. Thanks.
If you have a full album or EP, please send everything. Your favorite may not be mine, and the mood one day can be different the next.