{
  "schema_version": "1.0.0",
  "content_version": "1.0.0",
  "module_id": "m24",
  "title": "Bass Staff Basics",
  "seed": 710041,
  "preset": {
    "id": "bass-staff-beginner",
    "difficulty": "beginner",
    "item_count": 10,
    "candidate_set": [
      "G2",
      "A2",
      "B2",
      "C3",
      "D3",
      "E3",
      "F3"
    ],
    "pitch_range_midi": [
      36,
      59
    ],
    "tempo_bpm": 90,
    "meter": [
      4,
      4
    ],
    "hints": true
  },
  "purpose": "Name written pitches in the bass clef.",
  "instructions": {
    "student": "Name each pitch with its written accidental. Use ledger lines as a continuation of the same letter sequence.",
    "teacher": "Play each numbered question from this page. Use the same replay policy for all learners. Keep the answer section separate until the first response is recorded. For tapping tasks, record an observation on paper; use the online trainer for device-timed scoring.",
    "follow_up": "Read new bass positions from the clef each time, even after practicing treble exercises."
  },
  "examples": {
    "demonstration": {
      "id": "m24-712465-0",
      "seed": 712465,
      "kind": "staff",
      "events": [
        {
          "midi": 47,
          "onset_beats": 0,
          "duration_beats": 1.5,
          "velocity": 0.7,
          "voice_id": "triangle"
        }
      ],
      "choices": [
        {
          "id": "B2",
          "label": "B2"
        },
        {
          "id": "D3",
          "label": "D3"
        },
        {
          "id": "A2",
          "label": "A2"
        },
        {
          "id": "G2",
          "label": "G2"
        },
        {
          "id": "F3",
          "label": "F3"
        },
        {
          "id": "C3",
          "label": "C3"
        }
      ],
      "answer": "B2",
      "explanation": "This written note is B2 in the bass clef (123.47 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "B2"
        ]
      },
      "total_beats": 2
    },
    "comparison": {
      "id": "m24-712465-0",
      "seed": 712465,
      "kind": "staff",
      "events": [
        {
          "midi": 48,
          "onset_beats": 0,
          "duration_beats": 1.5,
          "velocity": 0.7,
          "voice_id": "triangle"
        }
      ],
      "choices": [
        {
          "id": "C3",
          "label": "C3"
        },
        {
          "id": "E3",
          "label": "E3"
        },
        {
          "id": "B2",
          "label": "B2"
        },
        {
          "id": "A2",
          "label": "A2"
        },
        {
          "id": "G2",
          "label": "G2"
        },
        {
          "id": "D3",
          "label": "D3"
        }
      ],
      "answer": "C3",
      "explanation": "This written note is C3 in the bass clef (130.81 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "C3"
        ]
      },
      "total_beats": 2
    },
    "seed": 712465,
    "comparisonSeed": 712465
  },
  "questions": [
    {
      "id": "m24-710041-0",
      "seed": 710041,
      "kind": "staff",
      "events": [
        {
          "midi": 43,
          "onset_beats": 0,
          "duration_beats": 1.5,
          "velocity": 0.7,
          "voice_id": "triangle"
        }
      ],
      "choices": [
        {
          "id": "G2",
          "label": "G2"
        },
        {
          "id": "B2",
          "label": "B2"
        },
        {
          "id": "F3",
          "label": "F3"
        },
        {
          "id": "C3",
          "label": "C3"
        },
        {
          "id": "E3",
          "label": "E3"
        },
        {
          "id": "D3",
          "label": "D3"
        }
      ],
      "answer": "G2",
      "explanation": "This written note is G2 in the bass clef (98.00 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "G2"
        ]
      },
      "total_beats": 2
    },
    {
      "id": "m24-710041-1",
      "seed": 717960,
      "kind": "staff",
      "events": [
        {
          "midi": 53,
          "onset_beats": 0,
          "duration_beats": 1.5,
          "velocity": 0.7,
          "voice_id": "triangle"
        }
      ],
      "choices": [
        {
          "id": "B2",
          "label": "B2"
        },
        {
          "id": "A2",
          "label": "A2"
        },
        {
          "id": "C3",
          "label": "C3"
        },
        {
          "id": "F3",
          "label": "F3"
        },
        {
          "id": "D3",
          "label": "D3"
        },
        {
          "id": "E3",
          "label": "E3"
        }
      ],
      "answer": "F3",
      "explanation": "This written note is F3 in the bass clef (174.61 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "F3"
        ]
      },
      "total_beats": 2
    },
    {
      "id": "m24-710041-2",
      "seed": 725879,
      "kind": "staff",
      "events": [
        {
          "midi": 47,
          "onset_beats": 0,
          "duration_beats": 1.5,
          "velocity": 0.7,
          "voice_id": "triangle"
        }
      ],
      "choices": [
        {
          "id": "B2",
          "label": "B2"
        },
        {
          "id": "A2",
          "label": "A2"
        },
        {
          "id": "D3",
          "label": "D3"
        },
        {
          "id": "F3",
          "label": "F3"
        },
        {
          "id": "C3",
          "label": "C3"
        },
        {
          "id": "E3",
          "label": "E3"
        }
      ],
      "answer": "B2",
      "explanation": "This written note is B2 in the bass clef (123.47 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "B2"
        ]
      },
      "total_beats": 2
    },
    {
      "id": "m24-710041-3",
      "seed": 733798,
      "kind": "staff",
      "events": [
        {
          "midi": 48,
          "onset_beats": 0,
          "duration_beats": 1.5,
          "velocity": 0.7,
          "voice_id": "triangle"
        }
      ],
      "choices": [
        {
          "id": "G2",
          "label": "G2"
        },
        {
          "id": "E3",
          "label": "E3"
        },
        {
          "id": "F3",
          "label": "F3"
        },
        {
          "id": "A2",
          "label": "A2"
        },
        {
          "id": "C3",
          "label": "C3"
        },
        {
          "id": "B2",
          "label": "B2"
        }
      ],
      "answer": "C3",
      "explanation": "This written note is C3 in the bass clef (130.81 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "C3"
        ]
      },
      "total_beats": 2
    },
    {
      "id": "m24-710041-4",
      "seed": 741717,
      "kind": "staff",
      "events": [
        {
          "midi": 48,
          "onset_beats": 0,
          "duration_beats": 1.5,
          "velocity": 0.7,
          "voice_id": "triangle"
        }
      ],
      "choices": [
        {
          "id": "A2",
          "label": "A2"
        },
        {
          "id": "E3",
          "label": "E3"
        },
        {
          "id": "B2",
          "label": "B2"
        },
        {
          "id": "F3",
          "label": "F3"
        },
        {
          "id": "G2",
          "label": "G2"
        },
        {
          "id": "C3",
          "label": "C3"
        }
      ],
      "answer": "C3",
      "explanation": "This written note is C3 in the bass clef (130.81 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "C3"
        ]
      },
      "total_beats": 2
    },
    {
      "id": "m24-710041-5",
      "seed": 749636,
      "kind": "staff",
      "events": [
        {
          "midi": 53,
          "onset_beats": 0,
          "duration_beats": 1.5,
          "velocity": 0.7,
          "voice_id": "triangle"
        }
      ],
      "choices": [
        {
          "id": "C3",
          "label": "C3"
        },
        {
          "id": "E3",
          "label": "E3"
        },
        {
          "id": "F3",
          "label": "F3"
        },
        {
          "id": "D3",
          "label": "D3"
        },
        {
          "id": "B2",
          "label": "B2"
        },
        {
          "id": "A2",
          "label": "A2"
        }
      ],
      "answer": "F3",
      "explanation": "This written note is F3 in the bass clef (174.61 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "F3"
        ]
      },
      "total_beats": 2
    },
    {
      "id": "m24-710041-6",
      "seed": 757555,
      "kind": "staff",
      "events": [
        {
          "midi": 48,
          "onset_beats": 0,
          "duration_beats": 1.5,
          "velocity": 0.7,
          "voice_id": "triangle"
        }
      ],
      "choices": [
        {
          "id": "E3",
          "label": "E3"
        },
        {
          "id": "F3",
          "label": "F3"
        },
        {
          "id": "D3",
          "label": "D3"
        },
        {
          "id": "C3",
          "label": "C3"
        },
        {
          "id": "A2",
          "label": "A2"
        },
        {
          "id": "G2",
          "label": "G2"
        }
      ],
      "answer": "C3",
      "explanation": "This written note is C3 in the bass clef (130.81 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "C3"
        ]
      },
      "total_beats": 2
    },
    {
      "id": "m24-710041-7",
      "seed": 765474,
      "kind": "staff",
      "events": [
        {
          "midi": 50,
          "onset_beats": 0,
          "duration_beats": 1.5,
          "velocity": 0.7,
          "voice_id": "triangle"
        }
      ],
      "choices": [
        {
          "id": "E3",
          "label": "E3"
        },
        {
          "id": "D3",
          "label": "D3"
        },
        {
          "id": "A2",
          "label": "A2"
        },
        {
          "id": "B2",
          "label": "B2"
        },
        {
          "id": "C3",
          "label": "C3"
        },
        {
          "id": "G2",
          "label": "G2"
        }
      ],
      "answer": "D3",
      "explanation": "This written note is D3 in the bass clef (146.83 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "D3"
        ]
      },
      "total_beats": 2
    },
    {
      "id": "m24-710041-8",
      "seed": 773393,
      "kind": "staff",
      "events": [
        {
          "midi": 53,
          "onset_beats": 0,
          "duration_beats": 1.5,
          "velocity": 0.7,
          "voice_id": "triangle"
        }
      ],
      "choices": [
        {
          "id": "D3",
          "label": "D3"
        },
        {
          "id": "F3",
          "label": "F3"
        },
        {
          "id": "E3",
          "label": "E3"
        },
        {
          "id": "A2",
          "label": "A2"
        },
        {
          "id": "B2",
          "label": "B2"
        },
        {
          "id": "G2",
          "label": "G2"
        }
      ],
      "answer": "F3",
      "explanation": "This written note is F3 in the bass clef (174.61 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "F3"
        ]
      },
      "total_beats": 2
    },
    {
      "id": "m24-710041-9",
      "seed": 781312,
      "kind": "staff",
      "events": [
        {
          "midi": 50,
          "onset_beats": 0,
          "duration_beats": 1.5,
          "velocity": 0.7,
          "voice_id": "triangle"
        }
      ],
      "choices": [
        {
          "id": "A2",
          "label": "A2"
        },
        {
          "id": "D3",
          "label": "D3"
        },
        {
          "id": "F3",
          "label": "F3"
        },
        {
          "id": "C3",
          "label": "C3"
        },
        {
          "id": "B2",
          "label": "B2"
        },
        {
          "id": "G2",
          "label": "G2"
        }
      ],
      "answer": "D3",
      "explanation": "This written note is D3 in the bass clef (146.83 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "D3"
        ]
      },
      "total_beats": 2
    }
  ],
  "answer_key": [
    {
      "number": 1,
      "question_id": "m24-710041-0",
      "answer": "G2",
      "label": "G2",
      "explanation": "This written note is G2 in the bass clef (98.00 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "G2"
        ]
      },
      "total_beats": 2
    },
    {
      "number": 2,
      "question_id": "m24-710041-1",
      "answer": "F3",
      "label": "F3",
      "explanation": "This written note is F3 in the bass clef (174.61 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "F3"
        ]
      },
      "total_beats": 2
    },
    {
      "number": 3,
      "question_id": "m24-710041-2",
      "answer": "B2",
      "label": "B2",
      "explanation": "This written note is B2 in the bass clef (123.47 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "B2"
        ]
      },
      "total_beats": 2
    },
    {
      "number": 4,
      "question_id": "m24-710041-3",
      "answer": "C3",
      "label": "C3",
      "explanation": "This written note is C3 in the bass clef (130.81 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "C3"
        ]
      },
      "total_beats": 2
    },
    {
      "number": 5,
      "question_id": "m24-710041-4",
      "answer": "C3",
      "label": "C3",
      "explanation": "This written note is C3 in the bass clef (130.81 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "C3"
        ]
      },
      "total_beats": 2
    },
    {
      "number": 6,
      "question_id": "m24-710041-5",
      "answer": "F3",
      "label": "F3",
      "explanation": "This written note is F3 in the bass clef (174.61 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "F3"
        ]
      },
      "total_beats": 2
    },
    {
      "number": 7,
      "question_id": "m24-710041-6",
      "answer": "C3",
      "label": "C3",
      "explanation": "This written note is C3 in the bass clef (130.81 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "C3"
        ]
      },
      "total_beats": 2
    },
    {
      "number": 8,
      "question_id": "m24-710041-7",
      "answer": "D3",
      "label": "D3",
      "explanation": "This written note is D3 in the bass clef (146.83 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "D3"
        ]
      },
      "total_beats": 2
    },
    {
      "number": 9,
      "question_id": "m24-710041-8",
      "answer": "F3",
      "label": "F3",
      "explanation": "This written note is F3 in the bass clef (174.61 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "F3"
        ]
      },
      "total_beats": 2
    },
    {
      "number": 10,
      "question_id": "m24-710041-9",
      "answer": "D3",
      "label": "D3",
      "explanation": "This written note is D3 in the bass clef (146.83 Hz at A4 = 440 Hz).",
      "notation": {
        "clef": "bass",
        "notes": [
          "D3"
        ]
      },
      "total_beats": 2
    }
  ],
  "record": {
    "learner": "",
    "date": "",
    "first_responses": "",
    "same_question_corrections": "",
    "new_question_check": ""
  }
}