Unlocking the Potential of Physical Modeling Synthesis with Serum

Hello everyone! I'd like to share one of my favorite aspects of synthesis with you - physical modeling synthesis, and more specifically, how to achieve it using Serum.

Serum is often known for its versatility as a synthesizer. You may associate it more with its prowess in subtractive synthesis, considering the extensive filters available, or its capability in additive synthesis. It also functions as a basic sampler and even allows for some frequency modulation. If you're adventurous enough, you might have explored its potential for West Coast synthesis, given its foldback distortion and features resembling a low-pass gate (LPG).

However, you may not associate Serum with physical modeling synthesis. And that's what I want to change today. So, let's dive right in and discover the surprising capabilities of Serum in the realm of physical modeling synthesis.

Understanding Physical Modeling Synthesis

Physical modeling synthesis, as per Wikipedia, is a methodology that incorporates mathematical models, equations, and algorithms to emulate a physical sound source and conform to the laws of physics. It might seem, at first, that you would require a specialized synthesizer to cater to such complex requirements.

Interestingly, if you conduct a simple Google search using the phrase "physical modeling in Serum," you'll encounter an array of articles and videos about physical modeling synthesis. However, there is a notable lack of information specifically about using Serum for physical modeling. This could easily lead one to conclude that Serum is, perhaps, ill-equipped for this particular type of synthesis.

I'm here to challenge that notion and demonstrate that Serum, despite appearances, has a surprising and quite effective capacity for physical modeling synthesis. So, let's continue and take a closer look.

Demonstration

As astonishing as it may sound, the ability to execute physical modeling synthesis in Serum is merely 12 clicks away. The depth of its capabilities is quite surprising. For instance, Serum can be used to emulate the nuanced sounds of a nylon guitar, changing the tonality with different picks and pick positions.

Beyond that, we can convincingly produce the sounds of woodwind instruments or simulate the resonant tones of pipes. We can even venture into creating beautiful, abstract pads that provide rich, textured soundscapes.

How is this feat possible within Serum, a synthesizer that isn't typically associated with physical modeling synthesis? The answer lies in the innovative usage of its features and a deeper understanding of the synthesis process. So let's move forward and unravel the mystery.

The Basics of Karplus-Strong Synthesis

To better understand the concept of physical modeling synthesis, let's delve into an intriguing technique known as Karplus-Strong synthesis. This method was elucidated in a groundbreaking paper published in 1983 titled "Digital Synthesis of Plucked String and Drum Timbres," which is considered a pioneer in the field of physical modeling synthesis.

The ingenious technique, formulated by Karplus and Strong, opened up a new avenue for simulating the sounds of acoustic instruments. Remarkably, their method sidestepped the need for intricate 3D models or comprehensive simulation of the laws of physics. Instead, they offered a relatively straightforward algorithm that produced realistic and compelling results.

In the Karplus-Strong synthesis process, an impulse or a burst of noise is introduced into a delay loop. This impulse then passes through a delay, which is quite short and determined by the desired frequency. Subsequently, the impulse encounters a low-pass filter within the loop. This process is repeated continuously, with the impulse being fed back into the loop over hundreds or thousands of cycles. Over time, the high frequencies of the noise diminish, causing it to morph into a sine wave.

This clever method echoes the acoustic properties of plucked string instruments as perceived by human ears. It's a simple yet incredibly powerful algorithm that paved the way for a revolution in the world of synthesizers. And, excitingly, this technique can be replicated within Serum. Let's explore how.

Physical Modeling in Serum

Now that we have a grasp on the Karplus-Strong synthesis technique, let's translate that understanding to Serum. This might be surprising, but this versatile synthesizer can indeed emulate the concept quite effectively.

Firstly, initialize a patch in Serum and deactivate Oscillator A. Switch on the noise engine, which will function as our sampler. Here, load a kick drum sample in one-shot mode; this provides a brief burst of noise, serving as the impulse required in Karplus-Strong synthesis.

The next step involves replicating the Karplus-Strong algorithm. This requires a delay with a feedback loop and a low-pass filter. Conveniently, Serum's delay module can offer these. Adjust the feedback level and link the channels to initiate the feedback loop. Exploring these settings can yield fascinating sounds, but there's a snag – the pitch tracking is tricky, rendering it challenging to play various melodies.

Though Serum's built-in delay module might not be entirely sufficient, there's an alternative hidden in the filter section – the comb filter. In particular, the Comb Filter L6 is a delay equipped with a 6 dB per octave low-pass filter in the feedback loop. By fine-tuning the settings of this filter, we can achieve quite a practical implementation of Karplus-Strong synthesis. Plus, this filter includes keyboard tracking functionality, resolving our previous issue.

In essence, this exercise unveils Serum's hidden potential for physical modeling synthesis. By understanding and manipulating the synth's features, we can emulate and explore a whole new universe of sounds.

Examples

To truly appreciate the breadth of physical modeling synthesis in Serum, let's explore some examples:

1. Bouncing Effect: In this example, we use the oscillators as impulse generators. Modulate the tuning and volume with an LFO to create a characteristic bouncing effect. This can provide an engaging rhythmic texture to your mix.

2. Hemiola Rhythm: The second example exhibits oscillators tuned at a perfect fifth ratio. This arrangement forms a rhythmic pattern often referred to as a 'hemiola'. It can produce an intriguing polyrhythmic feel, adding an intricate depth to your composition.

3. Guitar Emulation: The third example takes a stab at emulating a guitar-like instrument. When the note is released, the sound mutes, resembling a guitarist's hand muting the strings. This example provides an excellent illustration of Serum's potential in simulating real-world instruments.

4. Abstract Pad: The final example showcases an abstract pad, where the pitch is animated to induce a filter sweep effect. This sound can add a unique ambient texture to your production, demonstrating the synth's capabilities for creating abstract sounds.

Conclusion

Serum is a powerful synthesizer for physical modeling synthesis when used creatively. Its flexibility allows for a wide range of sounds, from mimicking real-world instruments to crafting unique synthetic textures. The power is in your hands to explore and discover the wealth of sounds it can produce.