“As Psychic Twin, Erin Fein’s songs are so illusory it’s sometimes hard to remember there’s only one person behind them. “In an ideal situation,” she says, “there would have been two of me singing and playing the music.” Her doubled-over vocals and counter-melodies ripple over a simple, pulsing beat, occasionally touched with tambourine or glockenspiel. In an ongoing series of 7"s, starting with he”