🎸 NeurAmpli: Guitar DSP Amplifier

NeurAmpli is a minimal & powerful virtual guitar amplifier (Amp Simulator) written natively in VB.NET. By pushing the NAudio architecture to its limits, it transforms a dry input signal from your audio interface into a compact, saturated, and musically rich even-harmonic tube tone with near-zero latency.

🌟 Key Features & Strengths

• ⚡ Dynamic WASAPI Engine (Exclusive/Shared): A dedicated UI toggle allows you to seamlessly switch between Exclusive Mode (completely bypassing the Windows native mixer for microscopic 10ms output buffers and maximum real-time responsiveness) and Shared Mode (perfect for practicing over YouTube backing tracks or Spotify with ~15ms latency). The stream gracefully auto-restarts upon switching without breaking the UI.

• 📈 192kHz Implicit Oversampling: Internal DSP engine tested to run natively at 192,000Hz. Operating at this extreme frequency not only offers crystalline precision but naturally prevents catastrophic digital aliasing ("fizz") when generating extreme high-gain distortion.

• 🔥 Asymmetric Tube Simulation with 2x Oversampling: The distortion (Drive) stage doesn't rely on artificial symmetric clipping. A Parametric DC Tube Bias offset is applied within the Math.Tanh transfer function. It's now heavily upgraded with internal 2x Oversampling (anti-imaging and anti-aliasing filters) to perfectly emulate the color and warmth of true thermionic vacuum tubes without generating high-frequency digital "fizz" artifacts.

• 🔊 6-Stage Advanced Cabinet Simulator: Instead of a basic low-pass filter, the Cab Sim algorithm mimics the acoustic mass and air movement of a large 4x12 Studio Cabinet using cascaded BiQuadFilter instances:

  • 75Hz HPF: Removes subsonic "boom" for a tight low-end.
  • 100Hz Peaking EQ: Simulates the resonant body of a large closed-back wood cabinet.
  • 4.8kHz Cascade LPF: Cuts the harsh top end while letting the tone breathe.
  • 3.5kHz Presence Notch: Beautifully captures the distinct mid-scoop of guitar speaker cones.
  • 6.0kHz Rolloff: Ensures a natural smooth fade-out matching real microphones off-axis.

• 🎛️ Comprehensive DSP FX Chain (With Dynamic Tweaker Rack): ALL effects are meticulously calculated to be completely Sample-Rate Independent.

  • Soft-Knee Noise Gate (Exponential dial curve, time constants auto-scaling with sample rate).
  • Dynamic VCA Compressor with Envelope Tracking (Adjustable Ratio and Threshold).
  • LFO Modulated Chorus highly upgraded with Cubic Hermite Interpolation for extremely clean (artifact-free) delay modulation.
  • Dark Analog Tape Delay (Low-pass filtered feedback loop for a degrading BBD tone).
  • 8-Tap Diffusion Reverb upgraded with High-Frequency Damping to absorb treble in the tail, simulating real acoustic rooms/springs.
  • LFO Tremolo (Adjustable Rate and Depth).

• 💾 Thread-Safe WAV Recording: A dedicated button allows for surgical high-resolution recording (wet loop) by asynchronously dumping massive buffer chunks in the background. It utilizes strict SyncLock synchronization to guarantee thread-safe stability without audio dropouts or memory leaks.

• ⛓️ Drag & Drop Signal Chain: Reorder your pedals on the fly. The engine dynamically rewrites the audio processing loop to accommodate any configuration (e.g., Delay before or after Drive).

• 🎵 Integrated Backing Track Player: Jam along with your favorite tracks. Supports real-time hardware resampling to 192kHz to maintain the highest audio fidelity while mixing external files into the exclusive audio stream.

• 🗃️ Studio Rack UI: Automatic form positioning logic that "docks" the Looper, Metronome, Tuner, and Backing Track around the main amplifier, ensuring perfect visibility on 1080p monitors.

• 🎨 Fluid UI: Integrated fast-presets, a responsive hardware-style VUMeter with peak-hold, and real-time Noise Gate status via a dedicated LED indicator.

🚀 Quick Start / Usage

1. Select the hardware input receiving your guitar from the dropdown menu.
2. Click ON (Boots with a Clean tone preset).
3. Feel free to tweak the Gain, EQ, or play with the built-in Presets (Crunch, Heavy Metal) in real-time!
4. Custom Presets: Tweak your tone to perfection, right-click any USR slot to save, and left-click it later to instantly recall your setup.

🛠️ Built With

• Visual Studio / VB.NET
• NAudio API (WasapiOut, WaveInEvent, DSP BiQuadFilter, BufferedWaveProvider)
• Win32 API Integrations (User32.dll) for borderless window dragging events.

📝 License

MIT License - Open Source Educational/Musical Project. Feel free to use these DSP functions as a foundation to build more complex VSTs or standalone pedalboards.