AES-2id: AES information document for room acoustics and sound reinforcement systems — Characterization and measurement of surface scattering uniformity

Provides recommendations for measuring room impulse responses for characterizing room acoustics and evaluating sound reinforcement system performance.

AES-2id: AES Information Document for Acoustic Measurement

AES-2id is an information document published by the Audio Engineering Society that provides recommendations for measuring the acoustic performance of sound reinforcement systems. While not a mandatory standard, it serves as an industry-recognized guideline used by live sound engineers, system designers, and consultants worldwide.

Scope and Purpose

The document covers techniques for measuring frequency response, maximum SPL, directivity, and distortion of loudspeaker systems in real-world installed conditions. It addresses the practical challenges of measuring in occupied and unoccupied venues where controlled laboratory conditions are not available. AES-2id provides guidance on excitation signals, measurement positions, environmental corrections, and result presentation.

Key Recommendations

AES-2id recommends using time-windowed measurement techniques to separate direct sound from room reflections. The log sine sweep (Farina method) is the preferred excitation signal for impulse response measurement because it provides excellent signal-to-noise ratio and separates harmonic distortion from the linear response. For transfer function measurement, the document recommends dual-channel FFT analysis with coherence weighting to assess measurement quality. Multiple measurement positions should be averaged to characterize coverage uniformity.

Deconvolution Method

The sweep deconvolution process involves convolving the captured room response with the inverse of the excitation sweep. This produces a time-domain impulse response from which frequency response, phase response, and decay characteristics can be derived. SonaVyx implements this method in its IR measurement tool using Rust DSP for high-performance frequency-domain deconvolution.

How SonaVyx Implements AES-2id

SonaVyx follows AES-2id recommendations for sweep generation, deconvolution, and transfer function measurement. The log sweep generator produces configurable sweeps from 20 Hz to 20 kHz with durations from 2 to 20 seconds. Coherence-weighted averaging helps identify measurement positions with poor signal-to-noise ratio. Multi-trace overlay allows engineers to compare measurements across multiple positions as recommended by the standard.