# Music Production Calc – Pitch/Speed Varispeed Ratio Converter

> Music Production Calc – Pitch/Speed Varispeed Ratio Converter is a paid API for AI agents from music-production-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-30).

Converts semitones, cents, speed percent, two frequencies, or two BPMs into a unified varispeed ratio with all pitch/speed equivalents.

## Facts

- Endpoint: GET https://music-production-calc.x402tookit.com/pitch-speed?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/music-production-calc-pitch-speed-varispeed-ratio-converter-9c0e6a8a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_pRD4_bi91pwRQ1kq39z3_

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability music-production-calc-pitch-speed-varispeed-ratio-converter-9c0e6a8a
```

Example prompt: What's the varispeed ratio and speed percentage if I pitch up by 3 semitones — and also show me what happens to a 120 BPM track?

## When to prefer this

Use this endpoint whenever you need to interconvert any pitch or speed representation — semitones, cents, speed percent, frequency ratio, or BPM ratio — into a single coherent varispeed ratio with all equivalents. Prefer it over generic calculators when you need multiple representations at once (e.g. semitones AND speed percent AND ratio) or when you want to see the downstream effect on a specific frequency or tempo.

## Known failure modes

- Missing or conflicting input group — only one input group (semitones, cents, speedPercent, fromHz+toHz, or fromBpm+toBpm) should be supplied at once
- Speed percent of -100 or below is invalid (zero or negative playback speed)
- Non-numeric or out-of-range values for frequency or BPM cause validation errors
- Partial frequency pair (only fromHz without toHz or vice versa) returns an error
- Partial BPM pair (fromBpm without toBpm) returns an error

## How this service works

Convert semitones, cents, speed percent, two frequencies or two BPMs into one varispeed ratio with all equivalents.

## Output

Returns a JSON object with the computed varispeed ratio, equivalent pitch shift in semitones and cents, octave fraction, speed percent, resulting frequency (hzAfter) and tempo (bpmAfter) if supplied, a human-readable summary, the detected input mode, the direction of change (isSpeedUp), and any warnings or disclaimers.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "hz": {
       "type": "number",
       "description": "Optional frequency to show after the change"
      },
      "bpm": {
       "type": "number",
       "description": "Optional tempo to show after the change"
      },
      "toHz": {
       "type": "number",
       "description": "Ending frequency in Hz (use with fromHz)"
      },
      "cents": {
       "type": "number",
       "description": "Pitch shift in cents (100 cents = 1 semitone)"
      },
      "toBpm": {
       "type": "number",
       "description": "Ending tempo (use with fromBpm)"
      },
      "fromHz": {
       "type": "number",
       "description": "Starting frequency in Hz (use with toHz)"
      },
      "fromBpm": {
       "type": "number",
       "description": "Starting tempo (use with toBpm)"
      },
      "semitones": {
       "type": "number",
       "description": "Pitch shift in semitones (give exactly one input group)"
      },
      "speedPercent": {
       "type": "number",
       "description": "Speed change in percent, for example 8 for +8 percent (more than -100)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "cents": {
       "type": [
        "null",
        "number"
       ]
      },
      "ratio": {
       "type": [
        "null",
        "number"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "hzAfter": {
       "type": [
        "null",
        "number"
       ]
      },
      "octaves": {
       "type": [
        "null",
        "number"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
  
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/music-production-calc-pitch-speed-varispeed-ratio-converter-9c0e6a8a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from music-production-calc.x402tookit.com](https://www.zero.xyz/host/music-production-calc.x402tookit.com/llms.txt)