Sound Wavelength

{
  "asOf": "2026-10-11T14:38:35.670Z",
  "degraded": false,
  "delayMs": null,
  "delayPerMetreMs": 2.913629,
  "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": null,
  "feetPerMillisecond": 1.126032,
  "frequencyHz": 1000,
  "halfWavelengthM": 0.17160731,
  "metresPerMillisecond": 0.343215,
  "notChecked": [
    "humidity (moist air is slightly faster: about +0.3 m/s at 20 C and 50% humidity)",
    "altitude: speed of sound depends on temperature, not pressure, but temperature changes with height",
    "…2 more"
  ],
  "periodMs": 1,
  "quarterWavelengthM": 0.08580366,
  "reasons": [
    "Speed of sound rises about 0.6 m/s per degree C.",
    "Each metre of distance adds 2.9136 ms of delay."
  ],
  "source": "c = 331.3 sqrt(1 + T/273.15) m/s for dry air; wavelength = c / f, computed locally",
  "speedOfSoundMs": 343.2146,
  "summary": "At 20 C sound travels 343.21 m/s: 1000 Hz has a wavelength of 0.34321 m (period 1 ms).",
  "temperatureC": 20,
  "verdict": "COMPUTED",
  "wavelengthCm": 34.321462,
  "wavelengthM": 0.34321462
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://audio-calc.x402tookit.com/sound-wavelength?frequencyHz=1000&temperatureC=20'

# 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/sound-wavelength?frequencyHz=1000&temperatureC=20' \
  | 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%2Fsound-wavelength
const res = await pay("https://audio-calc.x402tookit.com/sound-wavelength?frequencyHz=1000&temperatureC=20");
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/sound-wavelength?frequencyHz=1000&temperatureC=20")
    print(res.status_code, res.text)