alt Hacker NewsShow HN: OnKey – I'm a bad singer, so I built an app to show where I'm off-key
Hi all
I was pretty terrible at singing, now I’d say I’m bad but not terrible. This is because I’ve been using a singing app (won’t name it here) that scores me on my pitch and timing throughout the song so that I can improve.
Lately however, the app I’ve been using has flooded their song list with songs that aren’t originals. I didn’t like this at all as for me, it’s easier to try to improve when you’re singing along to the original.
So, I asked an agent (Claude Code) if it could write some code to listen to Spotify and also listen to me and see if it could detect both pitches and score me. It impressed me by writing some Python and showing me my pitch in the terminal!
It couldn’t go all the way though and detect the singer’s pitch in real time.
So I found the next best setup and built OnKey, a Mac app that needs to listen to the song once (it doesn’t save it) and then when it’s learnt the song (takes a couple of minutes), you can sing along to the pitch track that it’s learnt. OnKey is free to use and open source under the MIT license.
It can listen to Spotify, Apple Music, and YouTube playing in your browser with the right permissions.
During the build I found that someone had done something similar in Nightingale, but this requires a library of songs exported to disk and who has this in 2026 (maybe some of you ;) - but we need to help the normies too).
You can check out a demo video on the site of me singing (warning given) here: https://singonkey.app
The app sends out to find the song info (short Shazam fingerprint, and looks up song details), lyrics (from LRCLIB), and checks for updates.
The app never sends the music (it doesn’t save this to disk) and your voice. Everything you’d expect to stay private does.
It’s still weak in a few places:
- when the song’s backing is noisy it’s hard to pick the pitch track out
- sometimes it gets a note an octave off
- it’s limited to Apple Silicon Macs, M1 or later, and only macOS 14.2 up because extra drivers aren’t required past this point
- the scoring is built for beginners like me so it’s fairly easy on you
Would love for people to try it out and let me know what works and what doesn’t for them!
Comments
I am sure this app will be very useful for my wife and daughter, who spent the whole day singing at the top of their lungs. It will also be a benefit for me, as I’ll get to hear more accurate notes.
Ok, I'll be that one today. This seems entirely vibe coded... why is it using webview/tauri? It could be so small and smooth in swift with just a small change to the prompt. People used electron/tauri/whatever to make things easier to write and maintain, but if we're just vibing things anyway, can we go back to respecting resources, please?
I like the idea though. I was using a paid app doing something similar in the past. Keen to get back into it.
Singing is about so much more than just hitting the right notes. Breath management is one of the most important skills you can develop to improve your singing. Proper vocal technique helps you avoid injuring your voice when tackling difficult songs. Learning to recognize and use techniques like belting, twang, head voice, chest voice, vocal fry, etc., can really bring your singing to life. Prosody and rhythm training help you develop good timing (one of the most important aspects of music), and there's so much more to it.
This kind of app is great for getting started and getting a taste of what singing involves, but it would be awesome to cover these other aspects as well, or at least mention their existence for aspiring singers.
The main demo video uses the Red Hot Chilli Peppers as an example. A singing app, for learning to sing, and Anthony Kiedis used as the model.
Red Hot Chilli Peppers. Anthony Kiedis.
It's like if you had let Shaquille O'Neal teach you how to shoot threes.
What a fun idea! I love that the song doesn't have to be programmed in by the developer. Will give it a try.
Have you played the Rock Band and similar "rhythm games" that were all the rage in the Wii era? I don't know that it helped my singing per se but gave some incentive to practice.
In case anyone is interested, you can test your relative pitch perception (as opposed to producing the pitch) in this excellent Yale site: https://www.themusiclab.org/quizzes/td I got 15th [sic] percentile!
Didn't know that external apps can interact with Youtube in a tab in Safari.
Looks nice, I sing so badly that I never dare to try if not alone. Maybe this app will help me to improve just little that I can sing along happy birthday quietrly in a corner without anyone turning heads.
I think my daughter will love this. How about some simple gamification mechanism? A score or a star rating on how well you performed, maybe combined with a difficulty level?
This is a great learning tool! I wish I could use it on Linux. :)
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Can you exclude a section from scoring if it picked up a backing vocal instead of the melody?