simple.json

{
    "chords": [
        {
            "instrument": "Grand Piano",
            "pitched_notes": [
                {},
                {
                    "interval": {
                        "denominator": 4,
                        "numerator": 5
                    }
                },
                {
                    "interval": {
                        "denominator": 2,
                        "numerator": 3
                    }
                }
            ]
        },
        {
            "interval": {
                "denominator": 3,
                "numerator": 2
            },
            "pitched_notes": [
                {
                    "interval": {
                        "denominator": 2,
                        "numerator": 3
                    }
                },
                {
                    "interval": {
                        "octave": 1
                    }
                },
                {
                    "interval": {
                        "denominator": 4,
                        "numerator": 5,
                        "octave": 1
                    }
                }
            ]
        },
        {
            "interval": {
                "denominator": 2,
                "numerator": 3
            },
            "pitched_notes": [
                {},
                {
                    "interval": {
                        "denominator": 4,
                        "numerator": 5
                    }
                },
                {
                    "interval": {
                        "denominator": 2,
                        "numerator": 3
                    }
                }
            ]
        }
    ],
    "gain": 5.0,
    "starting_key": 220.0,
    "starting_tempo": 120.0,
    "starting_velocity": 64.0
}