Audio Calc
Convert a frequency ratio (3:2) to cents and semitones or back, name just and Pythagorean intervals and commas, apply to Hz.
MediaLiveeip155:8453Exactvia cdp
AudioCentsJust-intonationRatio
Calls · 30d
1
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 4 snapshots so far.
$24.31
Verified settled volume
1,175 settlements proven x402 by their on-chain EIP-3009 marker.
$0.020
Listed price
As published in the catalog. Always read the live 402 before paying.
1
Calls · 30d
Upstream's own call count for this endpoint, not ours.
1
Unique payers · 30d
Last called 2026-10-20 20:58Z
—
Upstream on-chain volume
Reported by the source catalog.
Paid to
0xb531320805C5BED1D46AEaDcF4F008FDF172DBDaThe wallet the 402 directs payment to. Its whole payment record — every payer, every chain — is on the merchant page.
Asset 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913
Provider
The payTo wallet does not resolve to a registered ERC-8004 agent. That is not a verdict on the service — most of the catalog is unregistered.
Live 402 challenge
Captured by the enrichment pass, not read just now. Prices can change — always read the 402 the endpoint answers with.
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"source": "cents = 1200 log2(ratio); just, Pythagorean and septimal interval ratios, computed locally",
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"Cents are logarithmic: 100 per equal-tempered semitone, 1200 per octave.",
"Recognised as perfect fifth."
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"verdict": "NAMED_INTERVAL",
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"resultHz": 660,
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"notChecked": [
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"how pitch is perceived: tiny commas are audible only as beating or drift",
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"octaves": 0.5849625,
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"Cents are logarithmic: 100 per equal-tempered semitone, 1200 per octave.",
"Recognised as perfect fifth."
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"degraded": false,
"resultHz": 660,
"semitones": 7.01955,
"disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
"notChecked": [
"which note names an interval takes in a given tuning (see /tuning-temperament)",
"how pitch is perceived: tiny commas are audible only as beating or drift",
"…1 more"
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"outputSchema": {
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"type": "http",
"method": "GET",
"queryParams": {
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},
"output": {
"asOf": "2026-10-11T14:38:34.612Z",
"cents": 701.955001,
"ratio": 1.5,
"baseHz": 440,
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"octaves": 0.5849625,
"reasons": [
"Cents are logarithmic: 100 per equal-tempered semitone, 1200 per octave.",
"Recognised as perfect fifth."
],
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"resultHz": 660,
"semitones": 7.01955,
"disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
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"how pitch is perceived: tiny commas are audible only as beating or drift",
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],
"x402Version": 1,
"alsoAvailable": {
"llms": "https://audio-calc.x402tookit.com/llms.txt",
"catalog": "https://audio-calc.x402tookit.com/catalog",
"message": "Audio Calc has 12 pay-per-call endpoints (Audio engineering maths for agents: sample rates, bit depth, bitrates, dB sums, SPL, LUFS, latency, tuning ratios and room modes.), from $0.02 a call. See the full menu and send your agents our way.",
"openapi": "https://audio-calc.x402tookit.com/openapi.json",
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"url": "https://audio-calc.x402tookit.com/tuning-temperament",
"path": "/tuning-temperament",
"what": "Frequencies, cents and ratios of the 12 notes in equal, 5-limit just, Pythagorean or quar…",
"price": "$0.02"
},
{
"url": "https://audio-calc.x402tookit.com/lufs-math",
"path": "/lufs-math",
"what": "Loudness maths: gain to a LUFS target or platform, resulting true peak vs ceiling, or com…",
"price": "$0.02"
},
{
"url": "https://audio-calc.x402tookit.com/sample-rate",
"path": "/sample-rate",
"what": "Nyquist frequency for a sample rate, plus the alias frequency and samples per cycle of a…",
"price": "$0.02"
}
]
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}Accepts
The payment requirements as published to the catalog. Read the live 402 before paying — a price here is a claim, not a quote.
0.02USDC≈ $0.02 USD
on Base · exact scheme
Pay 0.02 USDC on Base to 0xb531…2DBDa. The signed payment is good for 5 minutes.
- Paid to
- 0xb531…2DBDa
- USD Coin contract
- 0x8335…02913
- Payment window
- 5 minutes
- As published
- 20000 smallest units
20000units
on solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp · exact scheme
That figure is in the token’s smallest units. Roundhouse does not hold this contract’s decimals, so it is shown as published rather than converted.
- Paid to
- DUPiup…eEm8s
- Token contract
- EPjFWd…TDt1v
- Payment window
- 5 minutes
20000units
on Polygon · exact scheme
That figure is in the token’s smallest units. Roundhouse does not hold this contract’s decimals, so it is shown as published rather than converted.
- Paid to
- 0xb531…2DBDa
- Token contract
- 0x3c49…c3359
- Payment window
- 5 minutes
20000units
on Arbitrum · exact scheme
That figure is in the token’s smallest units. Roundhouse does not hold this contract’s decimals, so it is shown as published rather than converted.
- Paid to
- 0xb531…2DBDa
- Token contract
- 0xaf88…e5831
- Payment window
- 5 minutes
The catalog’s raw entry
[
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{
"bazaar": {
"info": {
"input": {
"type": "http",
"method": "GET",
"queryParams": {
"ratio": "3:2",
"baseHz": 440
}
},
"output": {
"type": "json",
"example": {
"asOf": "2026-10-11T14:38:34.612Z",
"cents": 701.955001,
"ratio": 1.5,
"baseHz": 440,
"source": "cents = 1200 log2(ratio); just, Pythagorean and septimal interval ratios, computed locally",
"octaves": 0.5849625,
"reasons": [
"Cents are logarithmic: 100 per equal-tempered semitone, 1200 per octave.",
"Recognised as perfect fifth."
],
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"verdict": "NAMED_INTERVAL",
"degraded": false,
"resultHz": 660,
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"which note names an interval takes in a given tuning (see /tuning-temperament)",
"how pitch is perceived: tiny commas are audible only as beating or drift",
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]
},
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"type": [
"null",
"string"
]
},
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"type": [
"null",
"number"
]
},
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"type": [
"null",
"string"
]
},
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"type": [
"null",
"number"
]
},
"centsFromEqualTemperament": {
"type": [
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"number"
]
}
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}
}Provenance
- Seen in the source catalog
- 2026-10-20 20:58Z
- Last indexed by Roundhouse
- 2026-10-22 12:40Z
- Last enriched (probe, favicon, geo)
- 2026-10-20 22:15Z
- x402 version
- 2
- Max timeout
- 300s
- Liveness probe
- HTTP 402
Hand this page to an agent
Copy the prompt and paste it into Claude, an MCP client or your own agent — it will vet this service and call it over the free read API. No key, no account.
GET api.roundhouseai.io/v0/endpoints
This endpoint's own trailing-30-day call count, as published by the upstream catalog and snapshotted daily. 4 snapshots so far. Verified volume counts only settlements with an on-chain EIP-3009 marker.
Show the promptHide the prompt
Using Roundhouse, look up the x402 service Audio Calc and tell me whether it is worth paying: what a call costs, whether the endpoint answered when last probed, and what its payment record actually shows. curl -s 'https://api.roundhouseai.io/v0/endpoints?q=Audio%20Calc' curl -s 'https://api.roundhouseai.io/v0/merchants/<the payTo wallet returned above>' Then call it: read the price from the live 402 at https://audio-calc.x402tookit.com/interval-ratio, never from a cached figure, and pay with an x402 client. The /v0 API needs an API key (`authorization: Bearer rh_live_…`) on everything except /v0/unified* and /v0/endpoints. Either pay over x402 (mint a personal key for $0.01 at GET https://api.roundhouseai.io/v0/test/x402), or ask me for an organization key, which I create at https://roundhouseai.io/dashboard/connections. If you have neither, ask before going further. If you do not have Roundhouse tools or skills installed, read https://roundhouseai.io/skill.md first — it is the whole procedure.