Extraction of the envelope from impulse responses using pre-processed energy detection for early decay estimation

Area of Science:

• Acoustics and Signal Processing
• Architectural Acoustics
• Psychoacoustics

Background:

• The Schroeder's backward integration method is standard for analyzing sound decay but has limitations.
• Classical methods struggle with early reflections, low signal-to-noise ratios, or missing direct waves, common in venues like Italian opera houses.
• Existing alternatives like Hilbert transform or non-linear techniques offer partial solutions.

Purpose of the Study:

• To propose a novel method for estimating early sound decay envelopes.
• To address limitations of the Schroeder's method in complex acoustic environments.
• To provide more accurate and representative decay parameters, especially for the initial decay phase.

Main Methods:

• Development of a pre-processed energy detection technique for envelope extraction.
• Application of the method to impulse responses measured in historical opera houses.
• Comparison with classical backward integration and preliminary perceptual analysis.

Main Results:

• The proposed method generates an envelope that accurately matches the early part of the sound decay.
• It performs well even in non-linear acoustic conditions and challenging measurement scenarios.
• Detailed information on the initial decay is successfully extracted.

Conclusions:

• The pre-processed energy detection method offers a robust alternative for early decay estimation.
• It provides more representative acoustic parameters, particularly in complex environments like opera houses.
• The method shows potential for improved acoustic analysis and design.