Get Vocal Remover splits MP3, WAV, M4A and AAC files into two stems with no signup, and files auto-delete after about an hour. Free use is up to 2 minutes and 50 MB, 3 splits a day, and the first split each day includes downloads. Credit packs cost $4.90, $9.90 or $19. Upload only audio you have rights to.

I wanted a fast, no-signup way for people to make karaoke tracks, acapellas and remix stems without installing software or paying a subscription.