← The evidence ledger
Evidence row 2202255
Observed , by sync.x402_bazaar/1.
- Kind
- listing
- About
- source_record x402_bazaar:https://audio-calc.x402tookit.com/spl-distance
- Recorded
- Previous row
- None: the first of its kind about this subject
- Body SHA-256
- 93df2f42117e9f5746d2463e5532deb47e23eb194c3dd3fb39ed1285a9917680
- Leaf
- 0x974649c95e9cde5da2455be949ee3632cfcc5791660576136aea0acdc832495e
What was observed
{
"endpoints": [
[
"x402",
"https://audio-calc.x402tookit.com/spl-distance"
]
],
"name": "Audio Calc",
"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": "Sound level at another distance (inverse-square law; line sources fall 3 dB per doubling), or the distance for a level.",
"extensions": {
"bazaar": {
"info": {
"input": {
"method": "GET",
"queryParams": {
"distance": 8,
"level": 90,
"refDistance": 1,
"source": "point"
},
"type": "http"
},
"output": {
"example": {
"asOf": "2026-10-11T14:38:35.934Z",
"changeDb": -18.0618,
"dbPerDoubling": 6.0206,
"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.",
"distanceM": 8,
"intensityWPerM2": 0.000015624999999999987,
"levelAtReferenceDb": 90,
"levelDb": 71.9382,
"notChecked": [
"air absorption, which grows with frequency and distance (several dB per 100 m at high frequencies)",
"reflections, reverberation and diffraction (indoors the level stops falling near the reverberant level)",
"…3 more"
],
"pressurePa": 0.079056942,
"reasons": [
"Inverse-square law: the level falls 20 log10(r2/r1) dB.",
"Ideal free field: real rooms and air absorption change this."
],
"referenceDistanceM": 1,
"soundPowerLevelPointSourceDb": 100.9921,
"source": "Free-field spherical (20 log10) and cylindrical (10 log10) spreading; p0 = 20 micropascal; I0 = 1e-12 W/m2, computed locally",
"spreading": "point",
"summary": "90 dB at 1 m becomes 71.938 dB at 8 m (point source, 6.02 dB per doubling of distance).",
"verdict": "COMPUTED"
},
"type": "json"
}
},
"schema": {
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"additionalProperties": false,
"properties": {
"method": {
"enum": [
"GET"
],
"type": "string"
},
"queryParams": {
"properties": {
"distance": {
"description": "Distance in metres to find the level at (use this, or targetDb)",
"type": "number"
},
"level": {
"description": "Sound pressure level in dB measured at refDistance",
"type": "number"
},
"refDistance": {
"description": "Distance of the measurement in metres (default 1)",
"type": "number"
},
"source": {
"description": "point (default, 6 dB per doubling) or line (3 dB per doubling)",
"enum": [
"point",
"line"
],
"type": "string"
},
"targetDb": {
"description": "A level in dB to find the distance for",
"type": "number"
}
},
"required": [
"level"
],
"type": "object"
},
"type": {
"const": "http",
"type": "string"
}
},
"required": [
"type",
"method"
],
"type": "object"
},
"output": {
"properties": {
"example": {
"properties": {
"asOf": {
"type": [
"null",
"string"
]
},
"changeDb": {
"type": [
"null",
"number"
]
},
"dbPerDoubling": {
"type": [
"null",
"number"
]
},
"degraded": {
"type": [
"boolean",
"null"
]
},
"disclaimer": {
"type": [
"null",
"string"
]
},
"distanceM": {
"type": [
"null",
"number"
]
},
"intensityWPerM2": {
"type": [
"null",
"number"
]
},
"levelAtReferenceDb": {
"type": [
"null",
"number"
]
},
"levelDb": {
"type": [
"null",
"number"
]
},
"notChecked": {
"items": {
"type": "string"
},
"type": [
"array",
"null"
]
},
"pressurePa": {
"type": [
"null",
"number"
]
},
"reasons": {
"items": {
"type": "string"
},
"type": [
"array",
"null"
]
},
"referenceDistanceM": {
"type": [
"null",
"number"
]
},
"soundPowerLevelPointSourceDb": {
"type": [
"null",
"number"
]
},
"source": {
"type": [
"null",
"string"
]
},
"spreading": {
"type": [
"null",
"string"
]
},
"summary": {
"type": [
"null",
"string"
]
},
"verdict": {
"type": [
"null",
"string"
]
}
},
"type": "object"
},
"type": {
"type": "string"
}
},
"required": [
"type"
],
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}
}
},
"lastUpdated": "2026-11-01T22:36:54.36Z",
"quality": {
"l30DaysTotalCalls": 2,
"l30DaysUniquePayers": 2,
"lastCalledAt": "2026-11-01T22:36:54.174Z"
},
"resource": "https://audio-calc.x402tookit.com/spl-distance",
"serviceName": "Audio Calc",
"tags": [
"acoustics",
"spl",
"inverse-square",
"noise"
],
"type": "http",
"x402Version": 2
},
"source": "x402_bazaar",
"summary": "Sound level at another distance (inverse-square law; line sources fall 3 dB per doubling), or the distance for a level."
}What the leaf hashes
{"body":"93df2f42117e9f5746d2463e5532deb47e23eb194c3dd3fb39ed1285a9917680","id":2202255,"kind":"listing","method":"sync.x402_bazaar/1","observed_us":1793646814754037,"prev":null,"subject":"x402_bazaar:https://audio-calc.x402tookit.com/spl-distance","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).
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- 0xf89e4cf087ad9c407b2c65f8a81efac40c8ae8a21926f158fbc2da49496af5c3
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- Day root
- 0x78fecaabbe319e56f5c4b80fc02e2052e198ad24781da8832a475ff65f2002d1
- Chained
- 0xdc35957db5d1371ca382b9152878ffece28ec7c5cb4f98fd71ddb367f8b999b2
- Published
- On Arc Testnet, block 70432815: 0x56b814612eb2e3e544153df3e91e1f7199106d1e430c7d8c6b653feeb9ebe9af