I need to make an audio recording of performing vocal and piano (acoustic piano, two different performers), using the "pocket studio" recorder (Tascam DR-07MKI if the model matters). I cannot bring any larger equipment or connect external microphones.
This recorder has two condenser microphones on the top. These microphones can be rotated to cross together or moved widely apart (this appears to be a common feature of many such recorders).
The manual talks very briefly something about X/Y and A/B modes but does not even clarify which one is which, leave alone when to use one or another. I tried some test recordings, both configuration do record sound. From Wikipedia, seems that X/Y is a "crossed" and A/B is a "opened" position. This still leaves the question about the optimal setup unanswered.
Which microphone setup (crossed together or flipped apart) should normally be used for recording piano and singer playing together in relatively silent room at close distance?