You can get hi-def music in a few formats: WAV, AIFF, DSD, ALAC, and FLAC (the latter two known as lossless-compressed format). As we mentioned earlier, you can download songs at a 24-bit/96kHz encoding—higher than the 16bit/44kHz found in CDs—but there’s debate around whether the extra data in 24/96 can even be heard by the human ear (so your dog might be the only one who notices the difference), but some audiophiles swear by it; do a blind test of each to figure out what might be best for you.