We go deep into the possibilities of the C4
The Source Audio C4 Bass Synth pedal is a cutting-edge, highly versatile tool that offers a treasure trove of sonic possibilities for bass players and guitarists alike. Whether you’re exploring massive synth textures, aggressive distortions, or deeply modulated tones, this pedal’s comprehensive suite of features and controls will undoubtedly elevate your sound. In this deep dive, we’ll explore everything from its basic functionality to its most advanced capabilities, showcasing why the C4 is not just another effects pedal, but an entire sonic landscape waiting to be discovered.
Disclaimer: This pedal was kindly provided by Source Audio for the purpose of this review. However, this does not influence our opinions or the content of our reviews. We strive to provide honest, unbiased, and accurate assessments to ensure that our readers receive truthful and helpful information.
Unboxing and First Impressions
Out of the box, the Source Audio C4 Bass Synth is ready to rock, packaged with everything you need to get started. You’ll find the pedal itself, all necessary cables, a 9V power supply, a quick reference card, and even some swag! At first glance, the pedal feels incredibly sturdy, encased in a solid metal chassis that promises durability and longevity. This pedal is designed to take the rigors of live performance and studio sessions without skipping a beat.
Controls and Features: What You See is Only the Beginning
The C4’s user-friendly design immediately stands out, featuring four main knobs and a few key buttons:
- Input: Controls the input level of your signal.
- Mix: Balances the dry signal with the synth voices.
- Control 1 and Control 2: These variable knobs adapt based on the preset you’re using, allowing for dynamic customization of each sound.
- 3-Way Switch: Lets you toggle between three top-level presets (#1, #2, and #3).
At the top of the pedal, you’ll find the ALT Control Button. By pressing this, you enter “ALT mode,” which changes the function of the Input and Mix knobs:
- Input becomes Sens Control: Adjusts the envelope sensitivity.
- Mix becomes Volume: Controls the master output volume.
The 3-way switch in ALT mode now lets you select between presets #4, #5, and #6. The pedal automatically exits ALT mode after five seconds, bringing you back to the original controls.
The footswitch allows you to engage or disengage the pedal, with an LED indicator showing its status. The C4 is powered by a 9V power supply, with both mono and stereo input/output options to accommodate a wide variety of setups.
The Default Presets: A Taste of What’s Possible
Out of the box, the Source Audio C4 comes with six default presets:
- Pure Octaves: Emphasizes octave shifting effects.
- Taurus: Emulates the classic Moog Taurus bass synthesizer sounds.
- EDM Swell: Provides dynamic synth swells with modulation.
- Poly Pitch Swell: Delivers layered polyphonic pitch shifting.
- Funk Dragon: Offers funk-inspired filter and synth textures.
- Flashlight Bass: Produces a punchy, modern synth bass tone.
These presets are a fantastic starting point, showcasing the range of sounds the C4 can create, from vintage analog textures to more modern, cutting-edge synth tones. Each preset explores different waveforms, pitch shifting, LFO controls, and more, allowing you to get a taste of the pedal’s extensive capabilities right away.
However, these six presets are just the beginning. The true power of the Source Audio C4 reveals itself when you dive into the Neuro App, a free preset-sharing and editing software that unlocks the full potential of the pedal.
Unleashing the Power of the Neuro App
While the default presets are impressive on their own, the real magic of the C4 lies in its ability to connect to the Neuro App. This app not only allows you to download and share presets from a growing library of over 10,000 community-created and Source Audio-designed sounds but also enables you to create your own custom presets and update the pedal’s firmware.
For many, simply accessing the preset library may be enough to explore the pedal’s vast capabilities. However, for those who want to truly push the limits, the editing functionality in the Neuro App is where the magic happens.
A Four-Voice Synth: Sculpting Your Sound
At the heart of the C4 is its four-voice synthesizer, which gives you immense flexibility in crafting your sound. Each of these voices can run its own waveform, modulation, and effects, allowing for intricate and complex sound design.
Before even touching the synth waveforms, the C4 allows you to route your dry bass signal through a range of distortion, filter, and LFO effects. This means you can use the pedal purely as a distortion or filter unit, providing the same dynamic and cutting-edge options you’d find in Source Audio’s other pedals like the Aftershock (for distortion) and Spectrum (for filters).
You can apply multiple types of distortion—from light overdrive to aggressive fuzz—and pair them with filters, like low-pass or envelope filters, for tones that evolve and interact with the intensity of your playing. Each voice can be modulated independently with LFOs, further expanding your sound palette. The result is a truly versatile unit that can function as everything from a high-end distortion pedal to an advanced filter or modulation unit, all before you even dive into the more complex synth features.
This gives you the ability to generate anything from gritty, driven tones to smooth, evolving textures—all routed through the same pedal, with control over each voice’s modulation. The flexibility to use these blocks in creative ways is one of the major strengths of the C4, offering endless possibilities for sound exploration.
Once you start exploring the synth side of the pedal, the true potential of the C4 begins to unfold.
Advanced Modulation and Synthesis Capabilities
Each voice on the C4 can be independently modulated, including your dry signal. Thanks to the dual LFOs, you can control speed, waveform, and depth, adding incredible movement to your sound. This modulation capability is especially useful for creating evolving textures, classic tremolo effects, and the dynamic shifts that are a staple of modern EDM and synth-based genres.
The synthesis capabilities of the C4 extend far beyond basic waveforms. Each voice can be assigned one of several types of synthesis:
- Monophonic Pitch: Modeled after classic analog pitch-shifting pedals like the Boss OC-2 or the Octavia, this mode allows you to adjust octaves and semitones and even harmonize the pitch. It’s perfect for creating deep, growling bass sounds or high, soaring leads.
- Polyphonic Pitch: This mode enables multiple pitch-shifted voices to play simultaneously, ideal for creating lush textures or ambient soundscapes.
- Saw Wave, Sine Wave, and Square Wave: These classic waveforms provide the foundation for rich, synth-like sounds. The C4 can’t run more than two saw, square, or sine waves at the same time, but this limitation is rarely an issue, as more than two oscillators could lead to overly harsh sounds.
With the combination of pitch-shifting, modulation, and waveform manipulation, the C4 allows you to create sounds reminiscent of classic Moog synths, modular setups, or even cutting-edge digital synths. Whether you’re after deep, throbbing bass tones or shimmering, ethereal leads, the C4 has you covered.
FM Synthesis: A New Dimension of Sound
One of the standout features of the C4 is its ability to perform FM synthesis, which adds an entirely new dimension to the pedal. By modulating the frequency of one oscillator with another, or even with your dry bass signal, you can generate complex, harmonic-rich sounds that range from bell-like tones to harsh metallic noises. This adds incredible depth and nuance to the sound palette, making the C4 a truly powerful synth tool.
Step Sequencer: Rhythmic Control
The C4 also includes a 16-step sequencer that can be applied to each of the four voices independently. This feature is perfect for creating rhythmic, evolving patterns that add movement and complexity to your performances. When paired with LFO modulation, you can generate intricate, modular-style sequences that breathe new life into your compositions.
Conclusion: A Game Changer for Bass Players
The Source Audio C4 Bass Synth pedal is far more than just a basic effects unit. It’s a full-fledged synthesizer, modulation station, and multi-effects processor all wrapped up in a compact, rugged enclosure. From the default presets to the powerful editing capabilities offered through the Neuro App, the C4 allows you to craft sounds that are both incredibly unique and deeply musical.
Whether you’re looking to expand your tonal palette with deep synth basses, shimmering leads, or aggressive distorted textures, the C4 offers unparalleled flexibility and creativity. Its intuitive controls, robust build, and vast range of sounds make it an essential tool for any bassist or guitarist looking to explore new sonic territories.
In the world of effects pedals, the Source Audio C4 stands as a game-changer, and for those willing to dive deep into its capabilities, the potential is limitless.
