Can't tell difference between mp3 and flac, what hardware do i need?

Would headphones make difference if i played flac files from Iphone?

if not, what about if i get this sound card for my computer: HT OMEGA Claro Halo PCI Sound Card, would Bose QC15 (currently have) headphones combined with this sound card improve the sound from mp3 to flac? Or will i need 5.1 or 7.1 / digital headphones?

i'm just trying to figure out where do people use flac files because i'm interested in improving sound quality.

IPhone can't play FLAC audio. FLAC auido is a kind of lossless auido format. Ithe sound is perfect and but the file is larger compared with MP3. If you want to convert audio formats, you can have a try with 4Videosoft Video Converter Platinum.