Pluckable Strings | Hacker News Reader

Pluckable Strings

string.spiel.com

705 pointsbcjordan119 comments

It is great that the author included some known pieces for you to "watch" (click the music icon on the bottom right). Of course one first goes to Bach to test the mettle. While "watching" BWV 578 one thing I immediately noticed was how the rhythm of the counterpoint stood out to me in a new way. I have seen many visualizers (the great https://www.youtube.com/user/smalin/videos deserves mention), but I have found most to have some sort of constant object moving around to visualization the tones (i.e. a ball moving up and down). In this case, there is no "moving object" that we follow and we are instead left with the tones in isolation. I greatly enjoyed seeing how this increased my appreciation of Bach's rhythmic counterpoint as I could see when multiple strings were plucked at the same time with the clear purple coloring. Amazing work!

Also love that MIDI velocity is mapped to pluck position, so higher velocity notes are brighter. This is a beautiful representation of physical modeling.

What I found weird is that there's only one guitar piece in the list: Asturias. The rest is keyboard music. And unfortunately, that piece shows weaknesses in the system. Notes get cut off, the rhythm is wrong, and there was one very loud buzzing sound, which suggests the buffer can't be filled fast enough.

Man, I didn't even notice the icons in the bottom corners. I thought it was just a quick toy on first pass which is a shame because loading existing songs is really cool.

I wonder how many other people close the tab without noticing the buttons like I did.

Plucking strings is usually synthesized using Karplus-Strong synthesis which is a very short delay line loop with a low pass filter. The delay gets excited with a short burst of noise. The length of the delay line tunes the string.

Karplus-Strong can be extended in ways to simulate different types of plucking, acoustic pickup at bridge, or electric pickup at any point along tbe string, and plucked at any point along the string. Body resonance can be simulated etc. It's a pretty fun synth technique to play with. Amazing to take beyond simulating conventional instruments.

Karplus Strong sounds kind of bad though, if your goal is accurate sounds of instruments. The reason it works at all is that the noise generates the initial high harmonics of a pluck, then a low-pass simulates the frequency-dependent decay of those harmonics.

But this is very primitive compared to a massive body of research on better simulation. The delay line works great though, that part hasn't changed.

The algorithm was discovered in 1983, and for how computationally cheap it is, I'd say it's pretty convincing. Waveguide synthesis is a generalization of the same idea, often with more realistic results.

Variations on Karplus-Strong synthesis can yield some pretty wacky, dry and plucky types of sounds. In the original paper, the authors propose a variant of the algorithm which involves randomly alternating the sign (+/-) of every sample in the feedback loop, which creates a lot more atonal information in the signal. There’s also a variation floating around which uses an allpass filter in the feedback loop to introduce inharmonicity in the signal, see for example https://www.youtube.com/watch?v=SpC3t1EVF_Q.

Really cool that plucking the strings near the edges gives a different timbre than plucking in the middle.

Oh hey, it does. But why? (Seems like the same thing is true on actual physical strings.)

See https://phys.libretexts.org/Bookshelves/Waves_and_Acoustics/...

Touching the string at different points will excite different vibrational modes. Notably if you pluck in the exact center you activate none of the even-numbered nodes, if you pluck around the 1/3 point that's optimal for activating the second harmonic, etc. You can never not activate the fundamental mode touching it in one spot but you activate it less if you get close to the edge.

The way strings resonate means the tone you hear contains the fundamental tone and a number of higher harmonics of that tone. Depending on where (and how) you play the string you can emphasise the harmonics more or the fundamental tone more.

Here for example is a piece made up largely of the harmonics (Portrait of Tracy Jaco Pastorius) https://www.youtube.com/watch?v=nsZ_1mPOuyk That's an electric bass and the bell-like sounds are harmonics. Basically he's just lightly touching the string in specific places to suppress the fundamental tone so you just hear the harmonics.

Whereas here (Stir it up - Bob Marley and the Wailers) https://www.youtube.com/watch?v=1hwL3S3Gtzs when the bass comes in, the player is holding his hand near the bridge (back of the strings) with the side of the palm resting on the strings to suppress all the harmonics so you only get the fundamental tone and it has this sort of muffled quality (because a lot of the brightness comes from harmonics).

I recently learned to grasp harmonics from learning how saturation works, this provides a good visualization using a sine wave: https://youtu.be/NO2OZ3UTy2k?si=2gS4vETZKiYli4DY&t=183

Dan Worrall's channel is incredible for these types of sound engineering topics.

https://www.youtube.com/@DanWorrall

> the player is holding his hand near the bridge (back of the strings) with the side of the palm resting on the strings to suppress all the harmonics so you only get the fundamental tone and it has this sort of muffled quality (because a lot of the brightness comes from harmonics).

Palm muting is one big technique to the more aggressive and chunkier metal sounds[1].

Even if you take out the music theory - or blatant disregard for - except kinda not, it's complicated, the different way you can create sounds with an electric guitar[2] in weird ways is quite amazing.

1: https://www.youtube.com/watch?v=yg4tKoiGoyM

2: https://www.youtube.com/watch?v=H4ax35i6aIY

This channel has lots of Youtube shorts about basic ideas in Black Metal guitar: https://www.youtube.com/shorts/c16tL6rdh7g

It's not just where you pluck the string: most electric guitars have a "neck" pickup and a "bridge" pickup (sometimes a third in the middle). The neck pickup is closer to the middle of the string, and the bridge pickup is close to the end of the string. Regardless of where you pluck, the bridge pickup has a significantly more prominent high-end, to the point of being a bit shrill when played in isolation. Typically rock guitarists play rhythm with the neck pickup so they don't overpower the vocalist, then lead with the bridge pickup so they cut through the mix without needing to amp the volume too loudly.

Why is this the case? It is funny that my guitarist's intuition seems very clear about it - "the string is tougher and clickier at the bridge compared to the neck, of course the tone is more shrill" - but in terms of actual analytical evidence I just have to say "something something Fourier coefficients" :) Refining the physical intuition a bit: I believe the boundary at the end of the string dampens lower-frequency (i.e. lower-energy) vibrations faster than higher-frequency vibrations, so the lower harmonics die off more quickly than the higher "nasal" harmonics.

Isn't it just the geometry of the guitar constraining the ends of the string to have zero amplitude? The fundamental has peak amplitude only at the center of the vibrating part of the string. Higher harmonics have peaks in amplitude at multiple places along the string, and the higher the harmonic the closer one of those maxima is to the bridge.

Bingo! It's all about harmonics' nodes. For a visualization, Cycfi Research has a great series on how pickup position affects tones. He also sells a "modeling pickup" based on this theory.

https://www.cycfi.com/2014/07/virtual-pickup-placement-part-...

The fundamental result of Fourier analysis is that we are saying the same thing :) Though I should have clarified that the kinetic energy is zero at the "boundary" (ie bridge).

IMO which answer you prefer depends on perspective:

- if you assume a wave can be broken down into sinusoidal overtones then your geometric approach is much more immediate and intuitive: sinusoidal overtones => higher overtones clearly have more kinetic energy near the boundary, just draw a picture.

- if you assume that higher-pitched overtones have more kinetic energy then the physics approach explains why they are sinusoidal. Not the specific shape unless you do the math, but the "gist" of the slope. If the overtones were more like square waves, with no real difference in shape between frequencies beyond the length of the rectangle, then the pickup position wouldn't matter. But they can't be, the overtones have to be more "trapezoidal." And in particular, the lower overtones must have a more gradual slope than the higher overtones.

The geometric approach makes a big (but correct) physical assumption for an easy analytical argument; the physical approach goes the other way, only depending on Newton's laws + a lot of elbow grease.

It does, and very cleverly too. The '?' button explains what's going on - he just takes the fourier analysis of the shape of the string when it's released, and plays tones from that.

Just like on a real string instrument! I was wondering if they implemented this, and they have! Colour me impressed!

It's shockingly easy to make it sound good! Someone who understands music please explain to me why this works so well, I'm amazed!

The notes assigned to strings are chosen to make up chords (harmony).

The four groups of strings make up four chords. Going clockwise, they are C, Am, F, G. This is a common chord progression[1] in pop music. It became popular because the chords sound good together.

https://en.wikipedia.org/wiki/%2750s_progression

A video to drive this home, with examples from pop songs: https://youtu.be/oOlDewpCfZQ

I should note that this is the same 4 chords as the '50s progression, but a different ordering (I V vi IV vs I vi IV V). One is associated with more recent pop/punk music and the others is more associated with doo-wop.

Even when making my own string it still sounds good. I didn't known I'm that gifted!

They are all chords (C, F, G, Am).

C/Am, F, G are adjacent in the circle of fifths so they will all play nice in a progression.

To flesh this out, the root notes of C and A minor are not that close in the circle of fifths, but the chords sound similar because they share 2 notes (C is spelled C, E, G, and A minor is spelled A, C, E). A common device in major keys is to take a part played over the "1" chord (C in this case) and play it again, or some close variation, over the chord 2 steps down (A minor in this case) to get a "kind of the same, but sadder" version of the same part.

As others said - they're chords. And not just any chords, but chords we know sound great together. (If you haven't seen the 'Pachelbel Rant' yet, you should, it's an entire comedy bit based on the fact that these chords are fundamental to music: https://www.youtube.com/watch?v=uxC1fPE1QEE)

If you click on the little notes in the bottom right, you can pick other sets of chords, which give a different "vibe". (Me, I'm partial to the Andalusian ones)

That's why common advice to people starting the guitar is "Three chords, you can play anything. Four, you control the mood. Five, you're a god among men"

Pachelbel is slightly more complicated than the default here, five chords instead of four (adding iii - F#m in the key of D that he used, or Em in the key of C which is the key that this defaults to). So I guess that makes Pachelbel a god among men.

Actually....Pachelbel used a major III

There is an acoustic version, you can tune it however you like, and choose from all kinds of chords, but once you chose a chord it has to be tuned precisely to that set of notes or it would be "out of tune".

Each course of strings on the webpage somewhat behaves and sounds like an "ovikannel" when you strum it manually.

Here's one that was found hanging on a wall but they were normally attached to an entrance door so the wooden balls would swing against the strings when the door was opened, and play the chime:

https://www.reddit.com/r/finnish/comments/dvd125/my_finnish_...

One of the commenters was quite curious as to what it would sound like. Well about like this.

FYI, in Chrome on Linux, there's a glitchy crackling noise. Maybe a buffer under run or something. It happens a lot more often if you strum lots of strings quickly.

It also happens in Firefox but a lot less.

Chrome on Windows as well.

Brave on Android also

Firefox on Android is fine

This can happen a lot with web audio stuff like this, it's the browser struggling to keep up.

Chrome on Android too

Yes, modifying buffer_size in audio_shader.js to 4096 completely fixes this issue on Windows (chrome).

Can confirm on Chromium/Linux.

Arc on MacOS too.

I also have serious popping in chrome on my mac.

This shouldn't happen.

The main reason is the use of createScriptProcessor.

This should be replaced with AudioWorklet. Use WASM + SharedArraybuffer for calculation.

The visual of picking the strings is great, I spent a lot of time on it, I believe the vote is also a recognition of this.

Here is a similar idea (karplus) implemented with Rust + WASM, which is much better in terms of audio quality:

https://jackschaedler.github.io/karplus-stress-tester/

I also wrote a simple api to use Rust wasm audio here:

https://glicol.js.org/

If you are interested in doing some use cases, leave a message. I am actively maintaining it recently.

No sound on firefox on mac or ipad, and glitchy sound on safari on mac

further idea: let strings resonate with the overtones of other strings being played

also: support different materials like steel/nylon/gut

reading some of the reactions to this, it amazes me how many free VSTs just need a web interface of some kind to suddenly become interesting and popular.

If you have a DAW there are so many interesting free sound generators on the internet. Just spitfire audio has their free lab VSTs which give you 60 VSTs to play with - and thats just one company.

https://labs.spitfireaudio.com/

Its all just missing the front end a DAW normally provides but is too complicated for people just looking to mess around with sounds.

It would be nice if he or she described the algorithm in more detail. A common and simple string-synthesis method is called Karplus-Strong, but this sounds a bit better.

In case you didn't see it, there's a little bit of detail given if you click the question mark in the upper left.

Make sure your phone isn’t on mute. On iPhone, the mute button. I was raising the volume to no avail.

Edit: I don’t know why I’m being downvoted, the mute button is very unintuitive. YouTube will play on a web page with mute on, but this page won’t.

You're not wrong. To this day I have no idea what my phone's mute button actually mutes and what it lets through.

I had the same issue. My phone is permanently muted so I forgot to even check that option.

Probably worth the app/os to give you a notice if you fiddle with the volume while muted.

Isn’t working on iOS 17.4, iPhone 14. Both in Safari and the App Store download.

Edit: yes I’d pay $2 to play with this. lol

Works for me on iOS 17.4.1, iPhone 15 Pro.

You need to take your phone off silent.

Yeah I thought it was broken on iOS too, then flipped the silent switch and it worked.

Well, this fixed it. I bet there is a lot of confusion for the people reporting it just works, while their phone is on silent. Seems to work on silent if you have headphones on.

Interesting. I actually like this behavior and wish more applications would use it!

Having thought about it, it makes sense for the web browser. Though I think the app should do something to bypass it, but I realize it is probably just a browser embed.

I peeked at the source code and it’s pretty wild to see this is what JavaScript can do these day.

Definitely getting it for my kids!

amazing work!

However, I must point out that if tonejs is used here, audio will quickly become a bottleneck or even memory leak.

It reminds me of a Karplus Strong project written in rust that I saw before. This project is of course visually minimal, but demonstrates the use of rust + wasm audio.

https://jackschaedler.github.io/karplus-stress-tester/

I wrote a simple api to use Rust wasm audio here:

https://glicol.js.org/

If you are interested in doing some use cases, leave a message. I am actively maintaining it recently.

Correction:

The cause of the popping glitches is createScriptProcessor

this! So fun to play with. Love that you can edit and reposition the strings.

Wonderful!

Nice demo, but for me, plucking the string gives a lot of static noise/crumbling sounds. Anyone else having this issue?

yes, me. Chrome 125, Linux x86_64, pipewire.

I'm on Windows 11, Brave browser. Using Sound BlasterX G6 DAC.

It will happen to everyone due to use of createScriptProcessor.

This should be replaced with AudioWorklet. Use WASM + SharedArraybuffer for calculation.

Here is a similar idea (karplus) implemented with Rust + WASM, which is much better in terms of audio quality:

https://jackschaedler.github.io/karplus-stress-tester/

I had a fun time making a game using MIDI with some friends for a game jam. There was a godot extension for MIDI (that I ended up mostly cannabalizing to get more control) and I used it to read and animate musical bars in a sort of guitar hero-y setup.

It was a fun project, although the game was a little rough around the edges to say the least.

I did not look at the source code yet, but is this some sorta physics modeling problem? Treat the strings as a a bunch of interconnected balls, then apply the force at point, compute other forces, interpolate a curve through the new state, then compute frequencies based on where the string was plucked? this is pretty cool

My guess is the strings are not modeled as balls balls as continuous lines with a set tension oscillating based on their length and thickness. It's presumably a bunch of trigonometry, but not the most insane modeling problem I've seen. Very cool none the less

What's the most insane one ?

The piano is a hard one. Best current result: Pianoteq.

https://www.modartt.com/pianoteq_overview

The question mark top left kind explains

I remember haring about someone creating a musical software model that was supposed to allow you to do things that you normally couldn't do i.e. pluck or strum a cymbal.

I tried to find it but never have.

Does anyone else know what it is?

physical modelling synthesis has been around since the 70s. Some instruments are really complicated and require a bunch of FM oscillators to nicely replicate some physical sounds - things like cymbals and other metallic crashes especially.

Very cool project, I love the drawing function, can bring to interesting ideas. Unfortunately, some songs are broken, MIDI file 404. The code tries to parse the empty response, instead of escaping early.

Wow, I just tried. It's super easy to use and super fun. Whatever you draw on the screen, you basically obtain something not bad. A new generation of audio games.

Well that’s rather lovely.

As a musician, it's super interesting looking at the JS source (if you're a developer) and seeing how he applies musical concepts like notes and progressions to code.

Hey all: don't miss the music button in the bottom right!!

You can play classical music on the simulated instruments. This is the nicest thing I've seen in a long time.

The built in static, I'm not sure if it's purposeful or not, but I like it. If it is purposeful, it's a nice touch.

That just put the biggest smile on my face since an old 2009 vintage app to simulate the guzheng.

I'm going to pick this nit, but are they pluckable or strummable? Sounds more like strumming.

If you pluck one of the sets of strings, it's like strumming. But you can pluck them individually, which is definitely NOT strumming.

If you have a sense of the song and it's not to your liking, don't be too pluckable.

Fun.

I went to the TLD and couldn’t make sense of how this is connected to that.

Why is each string actually two strings next to each other?

This is delightful! Thanks so much for sharing!

The sound does not seem to work on iPad?

That's seriously awesome!

Bookmarked for stress-relief

Very pleasant, thanks!

Very interesting

In a similar fashion a choir where you pull on lips, more of a gag page though. https://www.adultswim.com/etcetera/choir/

Really wish this wasn't so... nsfw. My kid would love it, but there's no way in the world I'm sending him this link.

Blob Opera might be more family friendly: https://artsandculture.google.com/experiment/blob-opera/AAHW...

https://d21u3ic0kp9e91.cloudfront.net/choir/04/index.html

here's the lips choir detached from the rest of adult swim

I let my toddler play with it for a while on my phone, he didn't enjoy it very much.

This is fantastic, and with the vowel has another dimension. Love it, thank you!

Whats nsfw about it?

Nothing I think. But I can see why some people will find the opposite.

Why? I honestly have no idea why anyone could consider this NSFW. I will absolutely be showing it to my kids.

The sticky lips may illicit impure thoughts.

Especially in his child, apparently. What an odd idea.

Scandalous!

That says more about the beholder.

Yup

Let me rephrase.

Sticky lips ARE eliciting impure thoughts.

I think the poster referred to other parts of the adult swim website. It's not NSFW, but more like M+ TV rating.

Yeah that just occurred to me too when someone posted a free-from-adult-swim link to the same thing.

The name is a bit of a clue.

Scroll down.

OMG, this is so insanely cool. Love it.

Doesn't seem like a gag to me. I find this one to be a lot more musically interesting. The "pluckable" demo makes it kind of hard to do anything musically interesting based on the constraints of the screen-based UI.

The blob one harmonizes in a very interesting way. I would love to know the algorithm. Maybe even enough to pull apart the source code or reverse engineer it.

IIRC the progressions are generated by a small neural network trained on Bach chorales.

Interesting idea.

I went to share it with some musician friends of mine, but first wanted to give them a TL;DR.

I tried to copy info out of the "?" dialog so that I didn't have to re-type the details but the page blocked the operation. That was enough for me to pass. I don't have time to do extra work to explain someone else's project.

"pluckable strings". Don't really need anything more exhaustive than that. The discovery process is part of the fun.

This seems like a case where a more generous take would be productive. The page itself is a tool that intercepts drags, it seems like an oversight, not intentional, that it also intercepts drags on the help page.

I totally agree. Many folks overlook the UX decisions they make when sharing a project. That's why (in the spirit of HN) I began with a compliment and provided information as to why I made the choice.

While I can cop to the fact that some may interpret my comment as "Please don't complain about tangential annoyances—e.g. article or website formats, name collisions, or back-button breakage. They're too common to be interesting." it seems there is an equal and opposite lack of consideration around "Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith. "

Here's the text extracted from a screenshot of the ? provided to ChatGPT so you don't have to do extra work.

Pluck by Murat

A math-based string simulator.

Download on Apple App Store for $1.99 [Image of Apple App Store download button]

- It's fun to have on iPad with multitouch, especially for kids (even 1 year olds). - Support this project

Both the audio and visuals are generated using the same math, rendered at different speeds so the eye can see.

No tricks or audio files are used: everything is calculated from raw sine waves, with a theory of how energy is released in a pluck. - The vibrations are modeled based on how far down the string you pluck from. - The velocity of midi notes are mapped to both pluck position, as well as pluck strength.

This YouTube video of a slow motion string pluck proves that our simulated result is very close to reality. [Embedded YouTube video of slow motion pluck]

Technical details: - Each string is simulated with 12 overtones (integer multiples of the note frequency) - To calculate amplitude of each overtone, we take the Fourier transform of the plucked string at the time the pick is released - Higher frequency overtones decay faster than lower frequency overtones - 72 strings x 12 overtones x 44,100 samples per second = 52,920,000 calculations per second - Audio buffer of 1024 samples are sent to the GPU to compute in parallel on each tick

There are several directions I can take this project from here: 1. Turn it into an interactive educational tool to teach physics of sound, timbre & music. 2. Turn it into a music learning tool for kids where songs are pre-made as chords that the user can pluck to learn rhythm and feel. 3. Turn it into an interactive art installation 4. Turn it into a game where i.e. a bouncing ball plucks the strings & you try to match the melody

If you are interested in any of the above, please get in touch at murat@ayfer.net or @moyfer.

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