Interval Ratio

{
  "asOf": "2026-10-11T14:38:34.612Z",
  "baseHz": 440,
  "cents": 701.955001,
  "centsFromEqualTemperament": 1.955001,
  "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.",
  "intervalName": "perfect fifth",
  "nearestNamedCentsAway": 0,
  "nearestNamedInterval": "perfect fifth",
  "nearestNamedRatio": "3:2",
  "nearestSemitones": 7,
  "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"
  ],
  "octaveReducedCents": 701.955001,
  "octaves": 0.5849625,
  "ratio": 1.5,
  "reasons": [
    "Cents are logarithmic: 100 per equal-tempered semitone, 1200 per octave.",
    "Recognised as perfect fifth."
  ],
  "resultHz": 660,
  "semitones": 7.01955,
  "simpleFraction": "3:2",
  "source": "cents = 1200 log2(ratio); just, Pythagorean and septimal interval ratios, computed locally",
  "summary": "Ratio 1.5 = 701.955 cents = 7.0196 semitones (perfect fifth); nearest equal-tempered interval is 7 semitones (+1.96 cents).",
  "verdict": "NAMED_INTERVAL"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://audio-calc.x402tookit.com/interval-ratio?baseHz=440&ratio=3%3A2'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - 'https://audio-calc.x402tookit.com/interval-ratio?baseHz=440&ratio=3%3A2' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.02 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.02" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.02 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Faudio-calc.x402tookit.com%2Finterval-ratio
const res = await pay("https://audio-calc.x402tookit.com/interval-ratio?baseHz=440&ratio=3%3A2");
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.02 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.02"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://audio-calc.x402tookit.com/interval-ratio?baseHz=440&ratio=3%3A2")
    print(res.status_code, res.text)