PartialString by Different Instruments is a free physical modeling synthesizer released in July 2026 for macOS, Windows and Linux.
Instead of playing recorded samples or relying on a conventional oscillator, the plugin simulates the movement of a plucked string in real time. Its finite-difference engine can generate organic plucks, metallic tones, unstable textures, soft inharmonic sounds and slowly decaying pads.
What Is PartialString?
PartialString is a virtual instrument developed by Christian Baker under the Different Instruments name.
The plugin uses finite-difference time-domain physical modeling, commonly abbreviated as FDTD. It numerically simulates how an excitation travels through a virtual string and how that movement changes over time.
A virtual pickup measures the displacement at a selected position on the string and converts the result into audio.
A Different Approach to Physical Modeling
Many physical modeling instruments simplify the interaction between an exciter and a resonator. PartialString takes a more computational approach by representing the string as a series of displacement points stored in memory.
Lower notes require longer simulated strings and therefore more calculation points. When the string is excited, the plugin calculates how the displacement propagates along its length.
This creates a direct relationship between pitch, string length, simulation accuracy and CPU consumption.
Shape the String Excitation
The String State section controls how and where the virtual string is excited.
The excitation position and shape can respond to MIDI velocity. This allows softer notes and harder performances to affect more than volume alone.
Moving the excitation point changes the balance of harmonics, much like plucking a real string closer to its center or nearer to the bridge.
Adjustable Pickup Position
The pickup position determines where the movement of the string is measured.
Changing this position can emphasize or reduce different harmonics. A sound can move from rounded and fundamental-heavy to thinner, brighter or more metallic without using a conventional filter.
This makes pickup placement one of the most important sound-design controls inside PartialString.
Pickup LFO for Movement and Sidebands
An integrated LFO can automatically move the pickup position across the virtual string.
Slow settings create gradual tonal movement, while faster modulation can introduce more complex sidebands and amplitude-modulation-style textures.
The LFO can reach audio rates, allowing PartialString to move well beyond conventional plucked-string sounds and into more experimental electronic territory.
Damped and Undamped Decay
Separate controls adjust the decay of the damped and undamped string states.
Short decay settings produce compact plucks and percussive tones. Longer undamped values allow notes to continue ringing and interacting, making the instrument suitable for drones and pad-like textures.
The damper can remain disabled, stay permanently active or behave more like a piano damper that closes when a MIDI note ends.
Model Accuracy as a Creative Control
The Accuracy parameter changes the precision of the physical simulation.
Higher settings produce a more detailed representation of the vibrating string but require additional processing power. Reducing the accuracy creates softer, less realistic and increasingly inharmonic results.
This means simulation quality is not only a technical setting. It can also become a creative sound-design parameter.
Up to Ten Simultaneous Strings
PartialString supports up to ten voices of polyphony, with each voice representing an independently simulated string.
The available polyphony is adjusted dynamically according to the computer’s performance and the length of the strings being calculated.
Playing several very low notes can require significantly more processing than playing notes in the middle or upper registers.
Automatic Overload Protection
The plugin includes several options for managing demanding low notes.
PartialString can prevent notes that are estimated to overload the system from sounding. It can also shift demanding notes upward by one or more octaves to maintain real-time performance.
This protection applies during real-time playback. Offline rendering or freezing inside a DAW can use the full calculation without the same live performance restrictions.
Sounds You Can Create With PartialString
- Natural and synthetic plucked strings
- Metallic percussion
- Experimental bass sounds
- Soft inharmonic keys
- Long decaying drones
- Pad-like physical textures
- Prepared-piano-style tones
- Abstract cinematic sound effects
The plugin is especially interesting when its more unusual controls are automated. Moving the pickup, changing the model accuracy or extending the undamped decay can transform a simple note into a continuously evolving texture.
Best Uses for PartialString
- Experimental electronic music
- Ambient and drone production
- Cinematic sound design
- Organic plucks for House and Techno
- Game audio and interactive sound
- Metallic percussion layers
- Creative resampling
- Physical modeling experiments
Plugin Formats and System Requirements
- Windows: VST3, Windows 10 or later, 64-bit
- macOS: AU and VST3, macOS 10.13 or later
- Mac architecture: Intel and Apple Silicon
- Linux: VST3, x86-64
- Plugin type: Virtual instrument
A compatible DAW or plugin host supporting one of the listed formats is required.
No AAX, CLAP or VST2 version is currently listed on the official website.
Apple Silicon Performance
Different Instruments recommends running an Apple Silicon-native or Universal version of the DAW on M-series Macs.
Using an Intel-only DAW through Rosetta 2 also forces the plugin through the translation layer, which can reduce the available performance for its computationally intensive string simulation.
Download Requirements
PartialString is available as a free or pay-what-you-want download.
The official store provides separate downloads for macOS, Windows and Linux. An email address is used to deliver the receipt and download access. Joining the developer’s mailing list is optional.
Visit the official PartialString website
License Information
The developer clearly identifies PartialString as a free or pay-what-you-want plugin.
However, detailed software license terms are not currently displayed on the main product page. The plugin should therefore not be described as open source or assigned broader usage rights that the developer has not explicitly published.
Important Limitations
PartialString can require considerable processing power, especially when playing low notes with high simulation accuracy and long decay settings.
The maximum ten-voice polyphony may be reduced automatically when the system cannot calculate every requested string in real time.
The interface is also currently fixed in size. Producers using high-resolution displays may find it smaller than modern resizable plugin interfaces.
Final Verdict
PartialString is one of the more original free synthesizer plugins released in 2026.
Its finite-difference engine provides a genuine alternative to sample libraries, wavetable synths and conventional virtual analog instruments. Pickup position, audio-rate modulation, damping and simulation accuracy offer enough control to move from recognizable plucked strings into metallic, unstable and atmospheric textures.
For ambient music, experimental electronics, cinematic scoring and producers interested in physical modeling, PartialString is a distinctive free VST3 and Audio Unit instrument worth exploring.
