Piano Companion is a music theory reference app for songwriters, producers, teachers, and students. Look up any of 1,500+ chords or 10,000+ scales instantly, build progressions, and explore harmony on iOS, Android, and Mac.
Whether you're stuck on a progression, blanking on a scale name, or just exploring — Piano Companion gives you the answer in seconds. Press the keys you know, and it tells you what you're playing.
Search by name or tap the keys you know. Piano Companion identifies what you're playing — even from a MIDI keyboard.
The Chord Progression Builder suggests chords that fit your key. Experiment with patterns, listen back, and find what sounds right.
See notes on the grand staff, fingering for both hands, intervals, degrees, and compatible scales — all in context, not abstract textbook diagrams.
This article will explain what CHD is, why it’s superior to ZIP, and provide a step-by-step guide to converting your files.
You are in trouble. You cannot convert without a cuesheet. You must build a .cue file manually using a text editor or download the correct cue sheet from Redump.org.
Drag and drop your extracted files or entire game folders directly into the NamDHC window.
CHDMAN and NamDHC are designed specifically to handle this. The tool reads the .cue file, maps out all the separate audio tracks, and compiles them perfectly into a single, unified .chd file. Your emulator will still play the game music flawlessly. Verifying and Playing Your New CHD Files
Presenting reproducible workflows tailored to common scenarios. Convert Zip To Chd
The short answer is , CHD is significantly better for disc-based game images. While both ZIP and CHD compress data, they do so in fundamentally different ways, leading to vastly different results.
./chdtool.sh -r /path/to/roms
The evolution of retro gaming emulation has brought massive libraries of classic disc-based games to our fingertips. However, storing games for consoles like the PlayStation, Sega Saturn, Dreamcast, and PlayStation 2 demands an immense amount of digital storage space.
To convert these files, you’ll need a utility called . This tool is included by default with any MAME installation. Method 1: Using the Command Line (Manual) This article will explain what CHD is, why
For those who prefer a visual interface, namDHC is a highly recommended tool.
chdman createdvd -i "game.iso" -o "game.chd"
Unpack the contents into a folder. You are looking for files like .bin , .cue , .iso , or .gdi . 2. Download and Set Up chdman Download MAME to get chdman.exe .
: Save the all2chd.bat file from its GitHub repository into a new folder. You must build a
Double-click your cue_to_chd.bat file. A command prompt window will open and automatically scan all subfolders, converting every compatible disc image it finds into a single .chd file. Once finished, you can safely delete the old BIN, CUE, and ISO files. Method 2: NamDHC (Best for Beginners)
unzip "your-game-file.zip"
Extract the MAME folder and locate the file named chdman.exe .
Piano Companion is a music theory reference app that gives musicians instant access to 1,500+ chords with inversions, 10,000+ scales, a chord progression builder, reverse chord lookup, and an interactive circle of fifths. It is available on iOS, Android, and macOS, and supports 40+ languages. Whether you are a beginner learning your first chords or a professional songwriter sketching ideas, Piano Companion provides the answers you need in seconds.
Tap the piano keys you know on screen or connect a MIDI keyboard, and Piano Companion identifies every matching chord and scale in real time. This is especially useful when you hear a chord in a song but don't know its name — just play the notes and the app tells you what they form.
Piano Companion is free to download on iOS, Android, and macOS. The free version includes core chord and scale lookups. A Pro upgrade unlocks additional features including all chord inversions, the full scale library, the chord progression builder, and the circle of fifths tool.
Yes. Connect any MIDI keyboard to your device and Piano Companion will detect the notes you play, identifying chords and scales in real time. This works on iOS (via Camera Connection Kit or Bluetooth MIDI), Android (via USB OTG), and macOS (via USB or Bluetooth).
Piano Companion is available on iPhone, iPad, Android phones and tablets, and macOS. Your chord libraries sync across devices, so you can start on your phone and continue on your Mac.
Available on every major platform. Start exploring chords and scales today.
