What Is Physical Modeling?

Sound Design

It seems today that many of the popular large synth engines have created a somewhat generic sound in synth and beat music. However, I sense the tides may be changing, as they constantly do in music, and more and more young producers are looking to make their mark with new, exotic timbres that would have been impossible to create in a bedroom in decades past. Enter physical modeling.

Physical modeling itself is not new, rather being rediscovered in our era. In the 90's, producers and synth enthusiasts swore that physically modeling real instruments was the next big thing. This never happened, and likely for various reasons. For one, the cost of more efficient CPUS allowed for more realistic samples to be integrated. At the same time, the technology to emulate realistic physical interactions of instruments (think bowed strings) was not being developed for the same reason. Why have a sound that sounds awkwardly like a computer emulating a human when you can just use samples? But now in 2019, the idea of creating sounds based on a physical objects could save us from the repetitive sounds we hear so often in electronic music. Popular artists such as Sophie, Flume, Iglooghost and Tycho are implementing physical modeling in new ways, and re-introducing producers and listeners alike to a taste of interesting and creative sounds.

Fundamentally speaking, physical modeling synthesis means modeling wave-forms after a simulated set of parameters that would exist as a physical instrument. Essentially, designing sounds to sound more like instruments. And of course, as a principle, most producers are familiar with this to some degree. However, have you ever thought about physical modeling in a more experimental way? What would happen if you had a six foot long steel string, resonating through a square bamboo body? What would that sound like? What about a giant nylon string attached from the ceiling to the floor? Is that instrument plucked or bowed? What kind of physical space would best suit these highly theoretical acoustics? You can quickly see how this can get quite abstract. How would you even go about attempting to design sounds like these?

Mechanisms and Methods

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On most synthesizers, you have your attack, sustain, decay and resonance envelope controls, which affect a desired waveform. In physical modeling, its more useful to describe your instrument by a comprehensive algorithm, because it more closely allows for subtle variation that would exist in a natural physical sound source. Rather than designing sounds, you can more accurately think of this as designing the physical object which will generate the sound.

This means that all the parameters on a virtual instrument emulating a physical mechanism are closely inter-related. This is one of the most confusing and frustrating problems for newcomers to these type of sound models. In virtual instruments like Sculpture, small UI adjustments can result in massive differences sonically. For deeper understanding, this algorithmic approach to modeling can be broken down in 2 essential categories:

  • Continuous Models

    Are sounds designed as bowed or blown, or more specifically sounds designed by continuous flows of energy into the instrument (like air or the motion of a bow).

  • Impulsive Models

    Are plucked or stringed models, which are sounded by an "impulse" of energy. These Instruments promptly decay once the "impulse" of energy is removed, and is lost as friction.

This is a totally different approach to synthesis and can be used to design incredibly rich timbres, both realistic and surreal. In addition, layering of sounds can be applied to create incredibly full sounding "hyper real" synth sounds. The track "Spring" from the latest Flume mix-tape is an excellent example. You can perceive the timbre of the lead synth melody distinctly as being a physically struck instrument, despite the fact that it is clearly a synth.

For me personally, I think the future of music could be enhanced by the idea of creating "impossible instruments". The possibilities are endless when you consider that you can create an endless range of modeled percussion as well. Ten foot bongo? Miniature glass jars? Giant wooden pallet? Wet metal? Why download the same generic percussion when you can set yourself apart completely through the creativity of your own sound design.

Software Instruments and Tools

Here are just a few VSTis which I find are on the cutting of edge of physical modeling synthesis. Ranging from strings to percs, springs and even water! Keep in mind this is a short list of instruments I have experimented with, however this is just the tip of the iceberg. If you want to find more physical modeling synths, there are plenty out there with all types of timbres, and at all price points. Some of these i have listed here are completely free, so you can load them into your DAW today. All of these are value packed though, and far exceed the sonic capabilities of sound banks and samples. If your the type of producer that loves getting their hands dirty and making breaking new sonic ground, all of these instruments are for you! And if your the type simply looking for a way out of sound bank-prison, most of these offer a practical element for creating lifelike instruments which, again, in all cases are superior to their sampled cousins. Note: I was not paid to review any of these products, I simply use and enjoy them myself and i think they are a great entry to the world of physical modeling synthesis. Enjoy!

PA3 Derailer

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The PA3 Derailer by Physical Audio Ltd. is a pretty forward thinking synthesizer. The Instrument has 2 primary elements. The first is a metal bar which can be bowed or struck. The other is a nonlinear mass/spring mechanism. The two can be joined, allowing for complex harmonic resonance to create entirely unique timbres. Derailer allows for 37 strike bars, 5 resonator bars per instance, and 81 mass/spring connections per instance. Mac users are the lucky ones here, because Derailer is an Audio Unit plugin that requires macOS 10.9 or higher. You can purchase Derailer here for $159

Lord of the Springs

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Lord of the Springs by Taron is an incredible VST for Windows (32/64) that features 88 voices of active spring systems. Conventionally, You can employ this VST to create traditional metallic sounds, such as bells, glockenspiels marimbas and more. However, at the experimental level, this VST can be made to make all kinds of sounds from insane "glossy", "smooth" pads to aggressive, metallic percussion. Lord of the Springs is incredibly valuable, and should be in every physical modelers arsenal since it comes at the amazing price point of... free! You can download Lord of the Springs for free, here.

GFM Koch

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Games From Mars has created this amazing plugin, a one stop shop where you build the punchiest percussion out there. Boasting an unusually vibrant sound, this plugin will give life to all kinds of emulated tonal percussion sounds ranging from bass to pianos and stabs. If your going for something in between a futuristic synth and physical percussive instrument, this synth is for you! This plugin is available both as an AU and VST for both Mac and Windows (64 bit systems only). The best part is, you can download GFM Koch entirely for free.

Learn More Here here


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Kaivo by Madrona Labs is a one-two punch sure to give hours of sound design to anyone interested in making genuinely unique sounds. Kaivo can create metal, strings, nylon, springs, chimes... the possibilities are practically endless! This instrument is so packed with so many features that allow for lifelike, realistic timbre control, that even small subtle changes to the instrument can give detail to an otherwise mundane sound (such as a sample of the instrument your trying to model). Speaking of samples, you can even incorporate those too! Kaivo includes a granulator and, and quick twitch of the knobs gets you into some experimental territory pretty quickly. Kaivo is available as a Audio Units plugins and as a VST for Mac OS and Windows. You can purchase Kaivo for $129 here.


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Strum is developed by Applied Acoustics and it is great. This synth is simple and elegant in it's design. Strum offers two independent string generators. The first emulates the sounds of basic string types, such as nylon, brass, etc. The second uses basic wave forms with the ability to adjust tension and position. Both generators are affected by the same envelope filter, tremolo and timbre controls. In addition you can use built in chorus, delay, reverb and a soft knee limiter. For all your string modeling needs, both experimental and conventional, you can get Strum completely for $129. Download it here.


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This one by xoxos kinda escapes description, your gonna have to hear and try it for yourself. Water emulates...well, water! It sounds ultra-realistic, but there is some level experimentation to be had. You can affect its pitch and adjust the timbre by way of ADSR controls, an envelope, depth, brightness, width and more! Again, you gotta try it. Water is available for Windows only and costs only $10. Get it here.


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Sylfid by Syflex is another excellent string instrument modeler, with an emphasis on simplicity. This synth allows for life-like emulation with impulse models, computing the movement of energy waves through the strings. The result is life-like decay and sustain! To add a little bit of experimentation on this one, your string is an adjustable spectrum between plastic and metal. This unlocks a variety of cool "life-like but yet abstract" timbres, while still maintaining an essence of a GUI and sensible controls. Sylfid-f2 is a VST only synth, available on Mac OS and Windows for $20 here.

Elder Thing

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Elder Thing by xoxos is giving us yet another synth that basically escapes description. This thing is a monster...literally! This synth emulates a vocal tract which can range from beastly to just downright creepy and ghostly! like Water, you kinda just got jump in and try it. You can also add your sound files and affect through Elder Thing, making this thing perfect for making anything you need to sound, well, monstrous! luckily it is available as a VST for Windows at a comfortable $25. you can download it here.


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Carillon by Tweakbench is a fairly straightforward bell and chime synth. However, since it does not incorporate samples, Carillon is capable of creating brilliantly resonating sounds, with a emphasis on modeling a harmonically resonant array of chimes and bells. A wide array of timbres can be used to create bells and chime sounds that far out-measure what would be possible otherwise with samples. You can get Carillon for windows. It costs $.99, and you can buy it here!

Categories: Free Stuff, Producer Tools