const loop = new Tone.Sequence(
  function (time, col) {
    const selectedPads = store.selectedPads
    const playingPads = selectedPads.filter(
      pad => pad.n === col
    )
    playingPads.forEach(pad => instrument.start(pad.m, time, 0, '1', 0))
  }, [ 0, 1, 2, 3, 4, 5, 6, 7 ], '8n')