Researchers from Carnegie Mellon University appeared to have solved the age-old problem of microphone bleed-through, using just a couple of cheap video cameras. Instead of recording sound using microphones, the cameras see the vibrations created by individual instruments and then translate that back into sound waves.
No matter how good microphones are, there are always going to be drawbacks when recording multiple instruments. In order to be able to edit the sound in post-production of just one instrument, they first have to be isolated. That’s why recording studios are set up usually with more than one room, or the instrument tracks are recorded separately and layered one on top of the other.