Methodology & Standards | ResonAia
Every tool on this platform is built on published acoustic-engineering formulas and measurement standards, not estimation. This page documents the standards we align with and the physics behind each calculation.
Measurement Standards
The acoustic definitions ResonAia's tools are built on (RT60, scattering, absorption) follow the same international standards used in professional acoustic measurement labs.
- Reverberation time (RT60)
ISO 3382-1:2009 / ISO 3382-2:2008
Defines how reverberation time is measured in performance spaces and ordinary rooms. This RT60 definition underpins how the Schroeder frequency is derived.
- Scattering & diffusion coefficients
ISO 17497-1 / ISO 17497-2
Defines the random-incidence scattering coefficient (reverberation-room method) and the directional diffusion coefficient (free-field method) acoustic literature uses to characterize diffuser performance — the theoretical basis for the sequence geometries the Diffuser Designer generates.
- Sound absorption coefficients
ISO 354 / ASTM C423
Defines the reverberation-room method for measuring sound absorption — the standard our absorber tools, currently in development, are designed to align with.
Diffuser Sequence Design Theory
Each diffuser geometry ResonAia generates is derived from a published number-theoretic sequence, not a heuristic or trained model. The well depths come directly from the sequence math.
- Quadratic Residue Sequences (QRD)
Well depths are derived from the quadratic residues of a prime number, producing the wide-bandwidth scattering pattern Schroeder diffusers are known for.
- Primitive Root Sequences (PRD)
Well depths come from the primitive roots of a prime modulus, producing an asymmetric scattering pattern with different diffusion characteristics than QRD.
- Maximum Length Sequences (MLS)
A binary-depth sequence generated from a linear feedback shift register, producing a thin profile with broadband, near-uniform scattering.
Room Mode Calculation
Problem frequencies are computed from your room dimensions using the standard rectangular-room equations — the same formulas documented in the glossary.
- Room mode calculation
Axial, tangential, and oblique resonant frequencies are computed from room dimensions using the standard rectangular room-mode equation, the same formula documented in the glossary.
- Schroeder frequency
The crossover frequency between modal and statistical room behavior is calculated from room volume using a representative RT60 value. Full Sabine-equation reverberation estimation from your room's actual absorption is on the roadmap.
What ResonAia Calculates — and What It Doesn't
Transparency about scope matters as much as the formulas themselves.
- Calculated today
Diffuser sequence geometries (QRD, PRD, MLS, and the other six types) and room mode / Schroeder frequency calculations are computed live from the room and geometry inputs you provide, using the published formulas above.
- In development
Absorption coefficient calculations and full Sabine-equation reverberation estimation are not yet live — the Absorber Designer is currently a product overview while that tooling is finalized. The standards above describe what those tools are being built to align with.
- Not a substitute for lab measurement
Even once live, these are physics-based predictions from input data, not certified lab measurements. For acoustic certification or critical applications, validate with on-site measurement performed to the ISO/ASTM standards above.
Standards Referenced
- ISO 3382-1:2009 — Acoustics — Measurement of room acoustic parameters — Part 1: Performance rooms
- ISO 3382-2:2008 — Acoustics — Measurement of room acoustic parameters — Part 2: Reverberation time in ordinary rooms
- ISO 17497-1 — Acoustics — Sound-scattering properties of surfaces — Part 1: Measurement of the random-incidence scattering coefficient in a reverberation room
- ISO 17497-2 — Acoustics — Sound-scattering properties of surfaces — Part 2: Measurement of the directional diffusion coefficient in a free field
- ISO 354 — Acoustics — Measurement of sound absorption in a reverberation room
- ASTM C423 — Standard Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberation Room Method
Diffusor-Designer ·
Glossar
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