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Show HN: Eigendrum - Draw any shape and hear what it sounds like as a drum (baselashraf81.github.io)

240 points by BaselAshraf81 ↗ HN
Hi HN, I built Eigendrum, a web tool that solves the 2D wave equation for arbitrary shapes so you can hear what they sound like as drums.

How it works: * Solves -∇²u = λu using finite element analysis (Kφ = λMφ) on a triangle mesh. * Validated to <0.1% error against closed-form solutions for circles (Bessel zeros) and rectangles. * Sound model factors in strike location, Rayleigh damping, and mallet width. * Includes Kac drums I & II to demonstrate identical sound spectra from different geometries. * No frameworks, build steps, or dependencies.

Repo and tests: https://github.com/BaselAshraf81/eigendrum

Happy to answer any questions about the FEM solver or Web Audio setup!

https://eigendrum.com/#p=circle

59 comments

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andai
Very cool. Number keys and QWERTYU (or clicking the rows on the right) trigger the "modes" in isolation, which are surprisingly microtonal.

Also you can draw your own drums! What! That's so cool

Jeff_Brown
I love it. I wish I could select materials.
BaselAshraf81
Thanks for reposting this! I'm the developer (BaselAshraf81) - happy to answer questions or hear suggestions here.

If you find it interesting, a star on the GitHub repo helps a lot.

And don't forget to follow me on github, I build cool stuff!

Waterluvian
I tapped twice and got nothing but sketchy popup ads suggesting I need to install a VPN. Does it work on safari mobile for anyone else?
stdatomic
I just entertained myself with this for 30 minutes.
discordance
Those ads are nasty and really take away from the cool stuff you build!
nxc18
Thanks, ChatGPT.
jmole
This reminds me of a tongue drum I have. Have you thought about building an iterative solver for specific scales?

It would be interesting if you could simulate and then print (or laser cut) your own instrument on demand.

uwagar
amazing stuff, congrats!
valleyer
If the author is here, do yourself a favor and rewrite the app's labels from Claudese to English.

"what the shape does not decide: Pitch is size and tension; fade is material and air. Neither is in the outline, so both are yours."

curt15
"No build step and no application backend: the mesh, the solve and the audio all run on your own machine."
b0ringdeveloper
I'm not sure if I'm learning a lot. All of the shapes and click locations basically sound the same to me.
mh-
Make sure your SoundBlaster16 drivers are loading properly, because I don't think I heard two clicks that sounded the same.
ttul
Try `1 + 0.16cos(4t) + 0.08cos(12t + pi/6) + 0.04cos(36t + pi/3) + 0.02cos(108t + pi/2)`
bowsamic
Very cool, reminds me of some of Aphex Twin’s percussive elements
_flux
This would be quite nice as a VST/CLAP for music production!
stavros
This website has a list of data vendors 200 pages long, and it forces you to uncheck each one if you don't consent. I decided to close the tab rather than deal with this illegal dark pattern.
aureate
The title alone sounds like this would be interesting, but I'll never know if it is because it has a trackers popup listing thousands of "partners" and a load of "legitimate interest" boxes ticked by default. This is Daily Mail level stuff, immediate back button for me.
letier
Not a fan of the cookie dialog. Had to close the page as there was no easy way to reject the ad cookies.
Ycros
what has the world come to when people beg for stars on github