# Audio Calc

Audio engineering maths for agents: sample rates, bit depth, bitrates, dB sums, SPL, LUFS, latency, tuning ratios and room modes.

## How to pay

Machine-payable over x402. USDC on: Base (eip155:8453), Solana (solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp), Polygon (eip155:137), Arbitrum One (eip155:42161).
No accounts. No API keys. No signup. The paying wallet is the account.

## Machine-readable

- OpenAPI: https://audio-calc.x402tookit.com/openapi.json
- x402 manifest: https://audio-calc.x402tookit.com/.well-known/x402
- Catalog (free): https://audio-calc.x402tookit.com/catalog
- Health (free): https://audio-calc.x402tookit.com/health
- Uptime (free): https://audio-calc.x402tookit.com/uptime

## Endpoints (12)

### GET /bit-depth — $0.02
Dynamic range, levels and smallest step for a PCM bit depth, theoretical SNR, and the bit depth needed for a dB range.
Params: bits?: integer, dynamicRangeDb?: number, fullScaleVolts?: number
Example: https://audio-calc.x402tookit.com/bit-depth?bits=16

### GET /bitrate-size — $0.02
Audio file size from bitrate and duration, or the bitrate or duration it implies; PCM size from rate, depth and channels.
Params: sampleRate?: number, bitDepth?: integer, channels?: integer, bitrateKbps?: number, seconds?: number, sizeBytes?: number
Example: https://audio-calc.x402tookit.com/bitrate-size?sampleRate=44100&bitDepth=16&channels=2&seconds=3600

### GET /buffer-latency — $0.02
Audio buffer size to latency in ms (one way and round trip) at a sample rate, or the buffer needed for a latency target.
Params: sampleRate: number, bufferSamples?: number, targetMs?: number, buffers?: number, converterMs?: number
Example: https://audio-calc.x402tookit.com/buffer-latency?sampleRate=48000&bufferSamples=256

### GET /db-sum — $0.02
Add, average or subtract sound levels in dB: total of several sources, N identical sources, or background-corrected level.
Params: levels?: string, count?: integer, total?: number, background?: number
Example: https://audio-calc.x402tookit.com/db-sum?levels=60%2C60%2C70

### GET /dbfs — $0.02
Convert between linear amplitude and dBFS, and get the RMS level and crest factor of a sine, square, triangle or sawtooth.
Params: amplitude?: number, dbfs?: number, shape?: string
Example: https://audio-calc.x402tookit.com/dbfs?dbfs=-6&shape=sine

### GET /interval-ratio — $0.02
Convert a frequency ratio (3:2) to cents and semitones or back, name just and Pythagorean intervals and commas, apply to Hz.
Params: ratio?: string, cents?: number, baseHz?: number
Example: https://audio-calc.x402tookit.com/interval-ratio?ratio=3%3A2&baseHz=440

### GET /lufs-math — $0.02
Loudness maths: gain to a LUFS target or platform, resulting true peak vs ceiling, or combining segment loudness.
Params: lufs?: number, target?: string, truePeakDbtp?: number, ceilingDbtp?: number, segments?: string
Example: https://audio-calc.x402tookit.com/lufs-math?lufs=-9.5&target=spotify&truePeakDbtp=-0.3&ceilingDbtp=-1

### GET /room-modes — $0.02
Room mode frequencies (axial, tangential, oblique) for a rectangular room, plus Schroeder frequency from RT60.
Params: length: number, width: number, height: number, temperatureC?: number, speedOfSound?: number, maxHz?: number, count?: integer, rt60?: number
Example: https://audio-calc.x402tookit.com/room-modes?length=5&width=4&height=3&temperatureC=20&rt60=0.5

### GET /sample-rate — $0.02
Nyquist frequency for a sample rate, plus the alias frequency and samples per cycle of a tone, and the guard band above 20 kHz.
Params: sampleRate: number, frequency?: number
Example: https://audio-calc.x402tookit.com/sample-rate?sampleRate=44100&frequency=30000

### GET /sound-wavelength — $0.02
Speed of sound in air at a temperature, wavelength and period for a frequency or the reverse, with delay per metre.
Params: frequencyHz?: number, wavelengthM?: number, delayMs?: number, distanceM?: number, temperatureC?: number
Example: https://audio-calc.x402tookit.com/sound-wavelength?frequencyHz=1000&temperatureC=20

### GET /spl-distance — $0.02
Sound level at another distance (inverse-square law; line sources fall 3 dB per doubling), or the distance for a level.
Params: level: number, refDistance?: number, distance?: number, targetDb?: number, source?: string
Example: https://audio-calc.x402tookit.com/spl-distance?level=90&refDistance=1&distance=8&source=point

### GET /tuning-temperament — $0.02
Frequencies, cents and ratios of the 12 notes in equal, 5-limit just, Pythagorean or quarter-comma meantone tuning.
Params: temperament: string, root?: string, a4?: number
Example: https://audio-calc.x402tookit.com/tuning-temperament?temperament=just&root=C4&a4=440

## Terms

Results are computed locally from standard audio, acoustics and loudness formulas, provided as is, with no warranty. Loudness targets are commonly published conventions that platforms change; verify them before delivery. Not for hearing-safety or legal noise compliance.