Understanding the Infinity System

Multichannel Polyphonic Sustain

Overview

The Infinity System is a multichannel system with true polyphonic sustain. Polyphonic sustain means that all vibrating strings will sustain indefinitely until muted. You can play single notes, layered harmonies, counterpoint, or chords that sustain forever.

Each string forms a closed feedback loop consisting of a pickup, a driver, and a controller that manages the energy fed back to the string and balances drive across strings, so no single string overpowers the others. The controller coordinates these per-string loops for stable and natural sustain. The drivers are electromagnetic exciters that keep the strings vibrating, while the pickups serve as sensors in the feedback path.

The system has been thoroughly tested in Thor and Valkyrie guitars and is now being offered as a stand-alone kit for qualified builders, complete with defined baseline requirements and detailed installation guidelines.

Design Philosophy

Sustain first, tone shaping later.

Infinity is not an aggressive sustainer. The goal is a neutral platform that preserves pick attack and the instrument’s natural character. The sustain controller’s sole function is to manage per-string feedback and maintain balance across strings at any fret or volume level. In most cases, a sustain setting of 4–7 is adequate.

There are no complex dynamics and timbre manipulations in the guitar itself. The system adds energy to the strings without modifying timbre.

The rationale is that post-processing using a DAW or external effects hardware can be utilized much more effectively to shape the envelope and timbre. Post effects processing handles the heavy lifting, including compression, dynamic ADSR envelope shaping for volume and tone, and overdrive or distortion, as well as synthesis. All these happen after the sustain stage.

Following this rationale, there is no “harmonic mode,” unlike many traditional sustainers. The goal is a clean, sustained fundamental with minimal harmonic shift across all strings and fret positions. We want a natural sound with no audible processing artifacts. Harmonic effects, and much more, are better achieved with downstream synthesis and processing.

Sound Clips

Here are two experiments in sustain and tone. Sonic Envelopes explores clean, evolving textures. Poly Fuzz dives into per-string distortion. Both show what is possible with polyphonic sustain when each string has its own voice.

In Sonic Envelopes, short audio snippets were recorded using only the Thor Infinity guitar to demonstrate polyphonic sustain and multichannel processing. No synths, no drums, no bass, and no overdubs. The raw guitar, tracked per string, was processed in Logic Pro using various audio effects plug-ins. The goal was to morph the sustained signal into new textures through post-processing. A typical multichannel signal flow was outlined: per-string preprocessing, per-string inserts and sends, then a poly mix bus for final glue.

This second part, Poly Fuzz, explores polyphonic distortion. Traditional distortion extends sustain and changes timbre by adding harmonics, but with multichannel sustain the first role is already covered. Timbre can be shaped in other ways, so distortion becomes just one of many waveshaping tools.

Multichannel Configuration

Multichannel means the system captures and processes each string independently. Each string has its own pickup output, allowing separate processing chains with different effects, routing, and dynamics. This separation enables complex signal paths, made practical by modern signal processing. In practice, you will need an audio interface with at least six channels and a DAW, or multiple hardware effects processors, to run per-string chains.

Mono Configuration

Often, you simply want to plug into an amp and play. An optional XR-Spectra pickup can be installed for simple, plug-and-play mono operation. The XR-Spectra is a full-range, low-impedance pickup with a very clean and wide (20 Hz to 20 kHz) frequency response that can be tailored using a Tone-Block. It feeds an onboard buffer so you can run a standard instrument cable to any amp or pedalboard. This gives you a familiar mono path without setting up a multichannel interface or per-string effects. This is the quickest way to demo Infinity’s feel without a DAW or multichannel rig.

Roland/BOSS Configuration

The Infinity System supports integration with Roland/BOSS devices through the standard GK 13-pin interface, making it compatible with a wide range of existing multichannel processors and synth systems. This allows builders and players to take advantage of Roland/BOSS units for signal routing, effects, and MIDI conversion.

Core Architecture

Each string forms a closed positive feedback loop: pickup → controller → driver → string. The string acts as a resonant filter that only responds to its fundamental frequency and its harmonics. Positive feedback drives it into oscillation, and the controller adjusts feedback gain to maintain even sustain and output across all strings.

Because each string acts as a resonant filter, we could, in theory, mix the feedback signals into a single driver. In practice, the Infinity system uses two driver coils: one for the treble side and one for the bass side. The treble coil covers the plain strings, and the bass coil covers the wound strings. This dual-driver approach improves efficiency because thinner strings have lower magnetic mass and require more power to drive into oscillation.

Block Diagram

Modules

The Infinity system is composed of three modules that snap together vertically to maintain a small footprint.

The Driver module (rightmost board in the picture below) contains the amplifiers for driving the coils. These are linear class AB amplifiers specifically chosen to deliver clean, noise-free output.
The MCU module (middle board in the picture below) contains the microcontroller, which includes provisions for flashing the firmware via USB.
The Main module (leftmost board in the picture below) integrates the MCU module and the Driver module and connects them to controls and the Cycfi standard 19-pin output jack.

The Nexus System

All configurations require the Nu Multi pickup and the Nexus system for power, routing, and I/O. In multichannel configuration, each string’s signal from the Nu Multi is routed to a separate output for per-string processing in a DAW or hardware effects rig. In mono configuration, the signal comes from the optional XR-Spectra pickup.

The Roland/BOSS configuration requires the Nexus GK-MIDI module. The GK-MIDI module provides the necessary signal and power routing to the 13-pin connector. Each string’s output from the Nu Multi pickup is sent to the corresponding channels on the GK interface for processing or pitch-to-MIDI conversion in Roland/BOSS devices such as the GR-55, SY-1000, and GM-800.

The Nexus system also provides in-guitar control via control voltages (CV). CV signals from onboard sources such as potentiometers, sliders, switches, and the E-Whammy are carried over the 19-pin cable to Nexus along with audio and power. Nexus supplies clean, conditioned power and keeps wiring tidy, allowing power, audio, and CV to share a single connection. The GK-MIDI module converts these control voltages to MIDI inside Nexus.

The Infinity System requires the Nu Multi pickup and Nexus-GK version 2.5 or later.

Installation Requirements

If you have read this far, you know that integrating the Infinity System is far more involved than a pickup swap. It is a complete infrastructure with specific requirements to ensure proper performance. These include pickup and driver placement, guitar setup, tuning and string gauge, as well as the type and placement of auxiliary pickups. The following guidelines are based on configurations we have tested extensively—a careful, conservative approach.

Here, we focus only on installing the core (drivers, controller, and Nu Multi integration). For the rest of the system, see the Further Reading section at the end of this document. Complete, detailed instructions will be provided. This section offers an upfront overview of what to expect so you can assess whether the system is suitable for your needs.

One basic assumption is that you are a builder with a working background in electronics or you are closely coordinating with someone who does. You are comfortable installing electronic systems, such as assembling a desktop PC. Ideally, you can read schematics. At minimum, you can follow block diagrams.

The initial release will have strict requirements, not because there are intrinsic limitations, but because I cannot test every possible configuration and I do not want to be tied up with ongoing support due to incompatibility issues. We will start with a baseline that is well tested and stable. Once you have this baseline up and running, you can expand and experiment with other configurations. I will rely on you, the builder, to explore and test those variations. It is simply not feasible for me to test everything.

These requirements ensure compatibility with the fully tested Infinity baseline.

Solid-body electric guitar
6-string only (7+ strings not supported for the initial release)
Non-multiscale (straight scale length)
Scale length: 25.5 in / 647 mm
Fret count: 21–24 frets (fretless is not yet supported in the initial release)
Low action.
1. Straight, no bow and minimal relief
2. No fret buzz
3. 12th fret high E: 1.2 mm
4. 12th fret Low-E: 1.5
High-E minimum string gauge: .008”
String spacing (at the bridge): 10.5 mm, center-to-center

Pickups and Pickup Placement

The sustain drivers occupy the neck position. There can be no neck pickup.
Nu Multi 6 at the bridge position 20-25 mm from the bridge saddles.
Sustain drivers at the neck position: as close to the fretboard as possible.
Optional XR-Spectra pickup paired with the Nu Multi, for mono operation.