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▲ 234 points

Show HN: Eigendrum - Draw any shape and hear what it sounds like as a drum

baselashraf81.github.io
by BaselAshraf81·6d ago·100 comments·view on 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

100 comments
“Everything’s a Drum!”

https://eigendrum.com/#s=__Ap66fz1em9-NXp7_6a6-0AJu1AAiTv6gK...

So in Dutch one expression for "that makes no sense" is "dat slaat nergens op", which literally translates to "that doesn't hit (slap, beat) anything".

A ruder variation of that is "dat slaat als een … op een drumstel", or "that hits like a … on a drum set".

For some reason I felt like sharing this trivia.

Aunty Donna were so wise.
Now try to draw a donut.
This is brilliant! I wish I had seen this a few years back!

Q: Generating higher quality sounds with a specified duration (e.g. within a 300ms margin) -- is it possible with your approach, is it hard, how would you go about that?

I'm asking because a few years back I had an idea for a breathwork/meditation app that would allow you to connect / control the breath duration using a gong sound. Example pattern: 4s in, 4s wait, 8-10s out. Next: use a feedback loop with the real user breathing pattern, slowly extend towards the goal.

Ended up with scaling it down to a "dot to stare at" + basic gong, because I realised how ridiculously chromatically complex the sound is. (my approach was to synthesise an envelope with a shape determined by time -- pity the fool who thought it was easy or even made sense!)

https://untested.sonnet.io/notes/projects-and-apps-i-built-f...

I got +100k people visiting it and still a couple dozen daily users running a 5+ min session, so I'm happy with it. But, the itch is still there, so I'd love to revisit my old nemesis so to speak :)

Also, if you want to chat about this, hit me up sonnet.io/posts/hi !

Anyone else seeing "net::ERR_SSL_VERSION_OR_CIPHER_MISMATCH"? Happens both in Firefox mobile and another browser that's a thin wrapper around Google's Chromium Webview. I'm surprised nobody mentioned it yet if firefox and chromium both struggle with this site. Or do they use a common TLS engine on Android?

Sadly http is not supported, it forces https for what I understand (from the title) to be a little web toy

Edit: same issue on Firefox desktop on Linux. It gets the redirect from github.io and then a ciphersuite mismatch. I now guess the host got some faulty update and it's not a me issue

Hi, I was propagating DNS nameservers, sorry for the delay.

Let me know if you still face any issues.

EDIT: The DNSSEC validation error was caused by a cached TTL mismatch during the nameserver migration. I've temporarily disabled DNSSEC while it clears up and am getting it sorted out.

same for me
This is so dang cool. I’m sorry that all people can do is complain!
Contemptible cookie dialog.
What, didn’t you want hundreds of companies track you while you try to get the audio work on a drum simulator?
Sometimes you guys sound like big babies
Separate to the concerns about privacy others have, I found some ear-splitting pitch errors with making very narrow asterisk-shaped drums with a number of spokes not divisible by 2 or 3. Good thing my volume was low.
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.

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.
Try `1 + 0.16cos(4t) + 0.08cos(12t + pi/6) + 0.04cos(36t + pi/3) + 0.02cos(108t + pi/2)`
This is very fun to play with and design different drums. I was able to make one that had 4 connected but distinct regions giving different pitches, then within each of those regions (which look like 4 lobes of different sizes) where you tap on that region will further change the sound! Then I realized I basically just made a hand pan.
Fun concept. Absolutely carcinogenic approach to monetization.
I disabled the ads 1 hours after I seen this but I totally forgot about the consent banner, sorry for that. Hope it didn't affect your experience much.
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

there's an amazing video on youtube about how metal bar/gong instruments (like gamelans) have different overtones, and regular western intervals instead of being consonant (like with vibrating strings) are dissonant - even perfect 5ths - and a totally different set of intervals are consonant (slendro and pelog tunings are a bit different for this reason).

thinking about it, each drum here would have totally different ideal scales to the others.

this is cool.

Audio doesn’t seem to work in mobile safari.
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?
actually too cool. very addictive, while changing different parameters and playing.
Could something like this be used to design speakers?
I would love you to get all this in JUCE or w/ever and make a plugin.

have you seen https://differentinstruments.com/ ?

This would be quite nice as a VST/CLAP for music production!
It seems to simulate only the membrane, and not the body of the drum, so no bass drum, no snare and no hi-hats?
I just entertained myself with this for 30 minutes.
I approve.
What a great visualizer tool!

Observation: I never saw the link between Wave Equation Solvers, Finite Element Analysis (Eigenvalues, Eigenvectors, etc.) and Cymatics -- until I visited the above web page!

Related:

Cymatics: Chladni Plate - Sound, Vibration and Sand:

https://www.youtube.com/watch?v=tFAcYruShow

Cymatics:

https://en.wikipedia.org/wiki/Cymatics

Can it remain stable at a certain MHz?
The tone is kind of snippy. It refuses to play when there would be numerical artifacts ("there would be numbers, and they would be wrong") and if your drawn shape self-intesects it complaint rather than just giving a reasonable answer with a warning (minimum crossing width, separate bodies).

Overall a cool tool, but pretty annoying. I point it out not really to criticize this project, but because I see a trend in software that has a holier-than-thou sort of paternalistic tone. LLMs are obviously rife with this, but I also see interfaces from some humans that give me the vibe of a snooty Parisian waiter.

I love it. I wish I could select materials.
I'm not sure if I'm learning a lot. All of the shapes and click locations basically sound the same to me.
Very cool, reminds me of some of Aphex Twin’s percussive elements
Thanks, ChatGPT.
Why does the submitted link redirect? Is that allowed on HN
> If you find it interesting, a star on the GitHub repo helps a lot.

I am genuinely curious, how?

Great! I vote for a skin tension control.
should be a vst intrument
Can you do this for a didgeridoo?
amazing stuff, congrats!
This is very cool stuff, indeed!
this is pretty cool
very nice! but having the "this space for rent" , space is the thing that realy says that it's someone doing there thing, everything is cool, no worrys, here play with a drum, and you knid of know that whoever might go in that space will be truely random, and interesting to some further subset of those that jump at an internet drum thing. thanks!
what has the world come to when people beg for stars on github
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.