OP-XY Multisample Converter - Web App

A browser-based tool to convert multisamples to OP-XY format with automatic silence trimming.

🌐 Live Demo: https://cfurrow7.github.io/opxy-converter

Built to convert patches created with Tyler Neely's TV-7 sampler - a browser-based sampling tool that outputs .elmulti and .wav files. This converter breaks them into individual sample hits for the OP-XY.

Features

• 100% Client-Side Processing - All conversion happens in your browser, no server needed, no uploads
• No Installation Required - Just open the HTML file in any modern browser
• Two Input Modes:
  • Elektron Mode: Convert .elmulti + .wav files from Elektron devices
  • Folder Mode: Process individual WAV files with note names in filenames
• Automatic Silence Trimming - Removes silence from beginning and end (-60dB threshold)
• Format Support:
  • PCM audio (16-bit, 24-bit, 32-bit)
  • IEEE Float audio (32-bit float)
  • Mono and stereo samples
• Download as ZIP - Get a ready-to-use .preset folder
• Privacy First - No data leaves your computer

Quick Start

Option 1: Use Online (Recommended)

Visit the live demo URL above and start converting immediately.

Option 2: Download and Use Locally

1. Download index.html, styles.css, and converter.js
2. Double-click index.html to open in your browser
3. Start converting!

Usage

Elektron Mode

1. Select "Elektron Mode"
2. Upload your .elmulti file
3. Upload the corresponding .wav file
4. Click "Convert to OP-XY Format"
5. Download the ZIP file
6. Extract the ZIP to get the .preset folder
7. Copy the .preset folder to the presets/ directory on your OP-XY
   • Connect OP-XY via USB
   • Enter disk mode: Press com button and select mtp
   • Navigate to the presets/ folder
   • You can create subfolders for organization (e.g., presets/elektron/)
   • Paste your .preset folder
   • Safely eject the OP-XY disk

Folder Mode

1. Select "Folder Mode"
2. Enter a preset name
3. Select multiple WAV files with note names in filenames
4. Click "Convert to OP-XY Format"
5. Download the ZIP file
6. Extract the ZIP to get the .preset folder
7. Copy the .preset folder to the presets/ directory on your OP-XY
   • Connect OP-XY via USB
   • Enter disk mode: Press com button and select mtp
   • Navigate to the presets/ folder
   • You can create subfolders for organization (e.g., presets/elektron/)
   • Paste your .preset folder
   • Safely eject the OP-XY disk

File Naming for Folder Mode

WAV files should include note information in their filenames:

Supported formats:

Piano C3.wav
C3.wav
piano_C#3.wav
Bass_Db3.wav
SampleName D-1.wav (negative octaves supported)
Strings_F#4.wav

The converter will:

1. Scan all WAV files
2. Extract note names from filenames
3. Trim silence from each sample
4. Create proper MIDI key mappings
5. Generate OP-XY compatible preset

OP-XY Setup

After conversion, install your preset on the OP-XY:

1. Connect OP-XY via USB cable to your computer
2. Enter Disk Mode on the OP-XY:
   • Press the com button and select mtp
   • The OP-XY will mount as a disk drive
3. Navigate to the presets/ folder on the OP-XY disk
4. Organize (optional): Create subfolders like presets/elektron/ or presets/custom/
5. Copy the entire .preset folder into your chosen location
6. Eject the OP-XY disk safely
7. Browse presets on your OP-XY - your new preset will appear!

Important Notes:

• The .preset folder contains both the patch.json and all WAV files
• You can create subfolders inside presets/ to organize your sounds
• Folder/file names may only contain: a-z A-Z 0-9 space # - ( )
• OP-XY supports both .wav and .aif files (mono and stereo)

Technical Details

Audio Processing

• Silence Detection: -60dB threshold
• Frame-by-frame Analysis: Checks all channels
• Format Support: 16/24/32-bit PCM and 32-bit IEEE Float
• Output Format: Converts to 16-bit PCM for optimal OP-XY performance
• File Size Reduction: 50-75% smaller than original (32-bit → 16-bit)

Key Mapping

• Automatically calculates key ranges between samples
• Each sample's range is split between neighboring notes
• First sample covers MIDI 0 to its lower bound
• Last sample covers its upper bound to MIDI 127

OP-XY Format

• Creates proper patch.json with all required fields
• Platform: OP-XY
• Type: multisampler
• Version: 4
• Includes engine, envelope, FX, and LFO settings
• Configures loop points (loops before end to avoid clicks)
• Sets velocity sensitivity and playback mode

Browser Requirements

• Chrome: 51+ (Recommended)
• Firefox: 54+
• Safari: 10+
• Edge: 15+
• JavaScript enabled
• Modern File API support

Privacy & Security

All processing happens 100% locally in your browser:

• No files are uploaded to any server
• No data is collected or tracked
• No internet connection required after initial page load
• Your samples stay private on your device

Deployment Options

GitHub Pages (Free)

1. Fork this repository
2. Go to Settings → Pages
3. Set Source to "main branch"
4. Your tool will be live at https://yourusername.github.io/repo-name

Self-Hosted

1. Upload index.html, styles.css, converter.js to any web server
2. No server-side processing required - just static file hosting
3. Works with any hosting: GitHub Pages, Netlify, Vercel, etc.

Local Usage

Simply open index.html in your browser - no server needed!

Troubleshooting

Conversion fails:

• Ensure WAV files are valid (not corrupted)
• Check that .elmulti file matches the WAV file
• Try using Chrome if having issues in other browsers

"Could not extract note from filename":

• Filenames must include note names like C3, D#4, Gb2
• Use one of the supported formats listed above
• Remove special characters except # and b

"No valid samples found":

• Ensure WAV files have note names in filenames
• Check that files are actual WAV audio files
• Verify files aren't empty or corrupted

ZIP file is empty:

• This was an early bug, now fixed
• Make sure you're using the latest version
• Clear browser cache and try again

Audio sounds distorted:

• Early versions had issues with IEEE Float format
• Current version properly handles all audio formats
• Re-download the latest version if experiencing issues

Development

Project Structure

web/
├── index.html      # Main interface
├── styles.css      # Beautiful gradient UI
├── converter.js    # All conversion logic
├── README.md       # This file
└── test.html       # Test page

Key Functions

• parseElmulti() - Parse Elektron TOML format
• readWavFile() - Read and parse WAV headers
• trimSilence() - Detect and remove silence
• createWavFile() - Generate output WAV files
• createPreset() - Build OP-XY patch.json
• downloadPreset() - Package and download ZIP

Dependencies

• JSZip (CDN): For creating ZIP files
• No other dependencies!

Contributing

Contributions welcome! This tool is free and open source.

Ideas for improvements:

• Drag & drop file upload
• Batch conversion support
• Custom silence threshold settings
• Sample preview player
• Advanced key mapping options

Credits

Created for the OP-XY community. Based on the original Python CLI tool.

Related Tools:

• Python CLI Version - Command-line converter with GUI

License

Free to use and modify. Created for the OP-XY community.

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Made with ❤️ for OP-XY users

Having issues? Open an issue on GitHub.