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Evidence row 2201544

Observed , by sync.x402_bazaar/1.

Kind
listing
About
source_record x402_bazaar:https://music-theory.x402tookit.com/note-freq
Recorded
Previous row
None: the first of its kind about this subject
Body SHA-256
f66a0a2bc596942c5c61f8d34742eccf55917b22d95ae9c8cc87f102d44aec31
Leaf
0x4cbffd5bf3d32031bd2b31e4f13be39f8ea2a0faea81a51d5d3537d6d3400988

What was observed

{
  "endpoints": [
    [
      "x402",
      "https://music-theory.x402tookit.com/note-freq"
    ]
  ],
  "name": "Music Theory",
  "owner_address": "0xb531320805c5bed1d46aeadcf4f008fdf172dbda",
  "raw": {
    "accepts": [
      {
        "amount": "20000",
        "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "extra": {
          "name": "USD Coin",
          "version": "2"
        },
        "maxTimeoutSeconds": 300,
        "network": "eip155:8453",
        "payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
        "scheme": "exact"
      },
      {
        "amount": "20000",
        "asset": "EPjFWdd5AufqSSqeM2qN1xzybapC8G4wEGGkZwyTDt1v",
        "extra": {
          "feePayer": "D6ZhtNQ5nT9ZnTHUbqXZsTx5MH2rPFiBBggX4hY1WePM",
          "transactionVersions": [
            0
          ]
        },
        "maxTimeoutSeconds": 300,
        "network": "solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp",
        "payTo": "DUPiupXtuox38dcGoXUKer5mAydCzmaHjrbQ66qeEm8s",
        "scheme": "exact"
      },
      {
        "amount": "20000",
        "asset": "0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359",
        "extra": {
          "name": "USD Coin",
          "version": "2"
        },
        "maxTimeoutSeconds": 300,
        "network": "eip155:137",
        "payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
        "scheme": "exact"
      },
      {
        "amount": "20000",
        "asset": "0xaf88d065e77c8cC2239327C5EDb3A432268e5831",
        "extra": {
          "name": "USD Coin",
          "version": "2"
        },
        "maxTimeoutSeconds": 300,
        "network": "eip155:42161",
        "payTo": "0xb531320805C5BED1D46AEaDcF4F008FDF172DBDa",
        "scheme": "exact"
      }
    ],
    "description": "Note name (C#4, Bb3) or MIDI number to MIDI, frequency in Hz and wavelength, with adjustable A4 reference pitch.",
    "extensions": {
      "bazaar": {
        "info": {
          "input": {
            "method": "GET",
            "queryParams": {
              "a4": 440,
              "note": "C4"
            },
            "type": "http"
          },
          "output": {
            "example": {
              "a4Hz": 440,
              "asOf": "2026-10-11T14:26:14.258Z",
              "degraded": false,
              "disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
              "enharmonicNames": [
                "C4"
              ],
              "frequencyHz": 261.6256,
              "midi": 60,
              "notChecked": [
                "historical or non-equal temperaments (just intonation, meantone, well temperaments)",
                "stretch tuning of real pianos",
                "…1 more"
              ],
              "note": "C4",
              "octaveConvention": "C4 = middle C = MIDI 60",
              "pitchClass": 0,
              "reasons": [
                "MIDI 60 is middle C (C4) in scientific pitch notation.",
                "Frequency = A4 x 2^((midi - 69) / 12)."
              ],
              "source": "computed locally (12-tone equal temperament)",
              "summary": "C4 = MIDI 60 = 261.6256 Hz (A4 = 440 Hz).",
              "verdict": "COMPUTED",
              "wavelengthCm": 131.1034,
              "wavelengthNote": "wavelength in air at about 20 C (343 m/s)"
            },
            "type": "json"
          }
        },
        "schema": {
          "$schema": "https://json-schema.org/draft/2020-12/schema",
          "properties": {
            "input": {
              "additionalProperties": false,
              "properties": {
                "method": {
                  "enum": [
                    "GET"
                  ],
                  "type": "string"
                },
                "queryParams": {
                  "properties": {
                    "a4": {
                      "description": "Reference pitch for A4 in Hz, 400 to 480 (default 440; baroque 415, Verdi 432)",
                      "type": "number"
                    },
                    "note": {
                      "description": "Note name with octave (A4, C#5, Eb3) or a MIDI number 0 to 127",
                      "type": "string"
                    }
                  },
                  "required": [
                    "note"
                  ],
                  "type": "object"
                },
                "type": {
                  "const": "http",
                  "type": "string"
                }
              },
              "required": [
                "type",
                "method"
              ],
              "type": "object"
            },
            "output": {
              "properties": {
                "example": {
                  "properties": {
                    "a4Hz": {
                      "type": [
                        "null",
                        "number"
                      ]
                    },
                    "asOf": {
                      "type": [
                        "null",
                        "string"
                      ]
                    },
                    "degraded": {
                      "type": [
                        "boolean",
                        "null"
                      ]
                    },
                    "disclaimer": {
                      "type": [
                        "null",
                        "string"
                      ]
                    },
                    "enharmonicNames": {
                      "items": {
                        "type": "string"
                      },
                      "type": [
                        "array",
                        "null"
                      ]
                    },
                    "frequencyHz": {
                      "type": [
                        "null",
                        "number"
                      ]
                    },
                    "midi": {
                      "type": [
                        "null",
                        "number"
                      ]
                    },
                    "notChecked": {
                      "items": {
                        "type": "string"
                      },
                      "type": [
                        "array",
                        "null"
                      ]
                    },
                    "note": {
                      "type": [
                        "null",
                        "string"
                      ]
                    },
                    "octaveConvention": {
                      "type": [
                        "null",
                        "string"
                      ]
                    },
                    "pitchClass": {
                      "type": [
                        "null",
                        "number"
                      ]
                    },
                    "reasons": {
                      "items": {
                        "type": "string"
                      },
                      "type": [
                        "array",
                        "null"
                      ]
                    },
                    "source": {
                      "type": [
                        "null",
                        "string"
                      ]
                    },
                    "summary": {
                      "type": [
                        "null",
                        "string"
                      ]
                    },
                    "verdict": {
                      "type": [
                        "null",
                        "string"
                      ]
                    },
                    "wavelengthCm": {
                      "type": [
                        "null",
                        "number"
                      ]
                    },
                    "wavelengthNote": {
                      "type": [
                        "null",
                        "string"
                      ]
                    }
                  },
                  "type": "object"
                },
                "type": {
                  "type": "string"
                }
              },
              "required": [
                "type"
              ],
              "type": "object"
            }
          },
          "required": [
            "input"
          ],
          "type": "object"
        }
      }
    },
    "lastUpdated": "2026-11-01T23:39:45.027Z",
    "quality": {
      "l30DaysTotalCalls": 2,
      "l30DaysUniquePayers": 2,
      "lastCalledAt": "2026-11-01T23:39:44.781Z"
    },
    "resource": "https://music-theory.x402tookit.com/note-freq",
    "serviceName": "Music Theory",
    "tags": [
      "music",
      "midi",
      "frequency",
      "pitch"
    ],
    "type": "http",
    "x402Version": 2
  },
  "source": "x402_bazaar",
  "summary": "Note name (C#4, Bb3) or MIDI number to MIDI, frequency in Hz and wavelength, with adjustable A4 reference pitch."
}

What the leaf hashes

{"body":"f66a0a2bc596942c5c61f8d34742eccf55917b22d95ae9c8cc87f102d44aec31","id":2201544,"kind":"listing","method":"sync.x402_bazaar/1","observed_us":1793646806601225,"prev":null,"subject":"x402_bazaar:https://music-theory.x402tookit.com/note-freq","subject_kind":"source_record"}

Proof

Fold these into the leaf in order, hashing each sorted pair with keccak256, to reach the root of (444186 rows).

  1. 0x4cc0046e64ee02dd7233ff6cad8ec5c590b006ab51500feceb0f57113aa09c64
  2. 0xcf88157f0c00c04059b58a842f9d8d23263e280754b0ae22b0f2bd80fd19fd7b
  3. 0x0642146d87f15a2ce472e485f7c8cb50a1c9d13ee91279e2ef852e1279ff2597
  4. 0x0eb28103706b80aa70093bd76ef8cbcfe9b4d2783ac54696c749d11dd0c34fa8
  5. 0xaa7b0f70b1250ba39e73ac5acc14cb301da30ccea08111b824389a27662e9b5f
  6. 0xb461aa3450a9997a8a567d88d2c48ffd68825dc9581acce0686a0d786c88ea8f
  7. 0x642a7e99e0528ff19870cdc21fc708a31b0643a9476aa89de21259eab38f0a1d
  8. 0x50cdad6905e0950fc8c8b29089d9c942d19e8281fc868c58d8171c3fc7f36826
  9. 0xe7e9e683f1772d7eb377b5f8660adbd169e2a0480688557dcf82dd447fee5c00
  10. 0xd0910c161ee3210f22a96d10e77dd46ebf3c06f561aeb5a66fadce489ef4cd62
  11. 0xa7f63fc52aa867079bccf41e1c316b83669bdc729aefcd02142cda6d20ee0f97
  12. 0x61b34ad045e6450b81b7a4502b2d97d0cc31cbac450cec30794ecaf30d1a78e3
  13. 0xc2ea6f7cdcf0c6904201c0d186a72f2a6fa2d355f41deec0e55aad057d5b8897
  14. 0xf01d425f0c05ac504062d9b471f06fbf10480b3526efb1ee77bb71aebd05f0de
  15. 0x67c99d356de30f9cfab88af48fbaa18909ef230dd09947e84da060bc03aca929
  16. 0x1068659ec8f2bcf26e4ad39786557a8c45d60e5ebba4fce2fb9962b2c9c59920
  17. 0xf9973981f80219d4f00fa9186b40a8144accc0c9875572fb79eaea312a21a187
  18. 0x4d205063c881c48edbbb37762a8d3bbb7444d4c42daa882f663a231893d25c35
  19. 0x365b161a4b68d750dcc4b3ecce1154a2163c87b08762079428e68f0ebb6a754e
Day root
0x78fecaabbe319e56f5c4b80fc02e2052e198ad24781da8832a475ff65f2002d1
Chained
0xdc35957db5d1371ca382b9152878ffece28ec7c5cb4f98fd71ddb367f8b999b2
Published
On Arc Testnet, block 70432815: 0x56b814612eb2e3e544153df3e91e1f7199106d1e430c7d8c6b653feeb9ebe9af

How to check it · This row as JSON