AMBIENCE1.0.1 Initial Release

Overview

Ambience is a high-quality, open-source algorithmic reverb VST3 plugin built on a 16-channel Feedback Delay Network (FDN) architecture. Designed with professional audio standards in mind, it delivers rich, natural-sounding reverberation ranging from intimate studio rooms to vast concert halls and beyond — with the precision and stability demanded by real-world production environments.

Ambience ships with 21 factory presets modeled after some of the world's most iconic acoustic spaces, including Abbey Road Studio 1 & 2, Vienna Musikverein, Amsterdam Concertgebouw, Boston Symphony Hall, Carnegie Hall, and more. Whether you need a tight drum room, a lush orchestral hall, a vintage plate, or an infinite ambient space, Ambience covers it all.

👉 Watch the Demo Video (動作デモ動画はこちら！)

Key Features

🏛️ 16-Channel FDN Reverb Engine

A research-grade Feedback Delay Network forms the acoustic core of Ambience:

• 16-channel FWHT Feedback Matrix: Fast Walsh-Hadamard Transform ensures dense, colorless diffusion with optimal mode distribution.
• Nearest-Prime Delay Allocation: Delay lines are tuned to unique prime numbers distributed on a logarithmic scale, guaranteeing mutual coprimality across all 16 channels and eliminating comb-filter artifacts at any room size.
• 7 Reverb Algorithms: ROOM1 / ROOM2 / HALL1 / HALL2 / PLATE / SPRING / GOLDFOIL — each with distinct topological routing, Allpass gain, and ER patterns.

🎛️ Professional DSP Modules

• Stage 2 GEQ Absorption (Välimäki-Liski): A 10-band biquad Graphic EQ cascade per FDN channel, solving a Weighted Least Squares system to achieve accurate, frequency-dependent RT60 targets across the full audible spectrum.
• ISM-Based Early Reflections: Image Source Method patterns tuned per algorithm, providing perceptually accurate pre-echo with full stereo imaging control.
• BandlimitedNoise LFO: Each of the 16 FDN channels is driven by an independent, mutually asynchronous low-frequency oscillator using a white noise source filtered by a 1st-order IIR — initialized via the Golden Ratio Weyl sequence to guarantee non-periodic modulation.
• ADAA Saturator (4 Modes): Anti-Derivative Anti-Aliasing saturation applied to the wet path. Modes: Warm (Vicanek x/√(1+x²)), Tape (Padé rational polynomial), Tube (asymmetric ADAA for even-order harmonics), Hard (hard clip + ADAA).
• Micro-Saturation (FDN Loop): An internal Padé saturator in the FDN feedback loop acts as a safety limiter, suppressing limit cycles without audible coloration.
• Output EQ: Linkwitz-Riley 12 dB/oct Lo Cut (20–500 Hz) and Hi Cut (1 kHz–20 kHz) applied exclusively to the wet path.
• Brick-Wall Output Limiter: -0.5 dBFS brick-wall limiter as the final stage, transparent under normal use.
• Ducking: Sidechain-style envelope follower with independent Threshold, Amount, Attack, and Release controls.