acoustic-mcp

An MCP (Model Context Protocol) server for acoustic room treatment design. Calculates absorption coefficients for porous absorbers, perforated panels, membrane absorbers, and Helmholtz resonators using the Transfer Matrix Method (TMM).

Designed to be used with Claude or other LLM clients to interactively design acoustic treatments for studios, listening rooms, and other spaces.

Tools

Tool	Description
calculate_porous_layer	Absorption of fibrous/foam absorbers (fiberglass, mineral wool, polyester, melamine) with optional air gap. Models: Delany-Bazley, Miki, Allard-Champoux.
calculate_perforated_panel	Absorption of perforated, slotted, or micro-perforated panels backed by an air cavity.
calculate_membrane_absorber	Absorption of membrane/panel absorbers (plywood, MDF, vinyl) backed by an air cavity.
calculate_helmholtz	Resonance frequency, impedance, and absorption area of a Helmholtz resonator.
calculate_multilayer	Arbitrary multi-layer absorber stacks — combine porous, air, perforated, and membrane layers.
optimize_absorber	Optimize absorber design for a target frequency or broadband NRC within a depth budget.
room_modes	Calculate room mode frequencies and Schroeder frequency for a rectangular room.
material_properties	Look up flow resistivity and density for 9 common absorber materials.
list_available_models	Catalogue of all supported acoustic models with parameters, valid ranges, and citations.

Quick Start

Requirements

• Python 3.10+
• uv package manager

Install and Run

cd acoustic-mcp
uv sync
uv run acoustic-mcp

Claude Code Integration

The .mcp.json at the project root configures the server for Claude Code:

{
  "mcpServers": {
    "acoustic-mcp": {
      "command": "uv",
      "args": ["--directory", "acoustic-mcp", "run", "acoustic-mcp"]
    }
  }
}

Run Tests

cd acoustic-mcp
uv run --with pytest pytest tests/ -v

Architecture

acoustic-mcp/
├── acoustic/
│   ├── server.py          # FastMCP server — tool definitions and Pydantic schemas
│   ├── tmm.py             # Transfer Matrix Method engine
│   ├── diffuse.py         # Diffuse field integration (Paris formula)
│   ├── optimizer.py       # Absorber optimizer and room mode calculator
│   ├── utils.py           # Air constants, NRC/SAA metrics, frequency axes
│   └── models/
│       ├── porous.py      # Delany-Bazley, Miki, Allard-Champoux, JCA
│       ├── perforated.py  # Ingard, Kristiansen, Maa MPP
│       ├── membrane.py    # Limp membrane / panel absorber
│       ├── helmholtz.py   # Helmholtz resonator
│       └── air.py         # Air gap layer
└── tests/

How It Works

The server uses the Transfer Matrix Method to compute absorption coefficients:

1. Each acoustic layer (porous material, air gap, perforated panel, membrane) is represented by a 2x2 complex transfer matrix
2. Layer matrices are multiplied front-to-back to get the total system matrix
3. Surface impedance is extracted assuming a rigid wall backing
4. Absorption coefficient is calculated from the reflection coefficient: α = 1 - |R|²
5. Standard metrics (NRC, SAA, octave-band summary) are computed from the absorption curve

Acoustic Models

Porous Absorbers

Four empirical/semi-empirical models for fibrous and porous materials. Each takes frequency and flow resistivity (σ) as primary inputs.

Model	Source	Notes
Delany-Bazley	Acustica 23 (1970)	Original empirical model
Miki	JASE 11(1) (1990)	Improved low-frequency behaviour. Default.
Allard-Champoux	JASA 91(6) (1992)	Separates viscous and thermal effects
JCA	Johnson (1987) + Champoux-Allard (1991)	5-parameter microstructure model

Perforated Panels

Model	Source	Use Case
Ingard	JASA 25(6) (1953)	Macro-perforated panels (holes > 1 mm)
Kristiansen-Vigran	Applied Acoustics 43 (1994)	Slotted panels
Maa	JASA 104(5) (1998)	Micro-perforated panels (holes < 1 mm)

Other Layers

• Membrane: Mass-law impedance sheet (Kuttruff 2009)
• Helmholtz resonator: Ingard formula with viscous losses (Kinsler et al. 2000)
• Air gap: Lossless propagation layer (Allard & Atalla 2009)

Material Database

Material	Flow Resistivity (N·s/m⁴)	Density (kg/m³)
OC703 Fiberglass	10,000–16,000	48
OC705 Fiberglass	20,000–32,000	80
Rockwool 60 kg/m³	8,000–14,000	60
Thinsulate SM600L	3,000–5,000	16
Basotect Melamine	3,000–8,000	10
Soft Polyester Batting	1,000–3,000	20
rPET Felt (Soft)	5,000–12,000	100
rPET Rigid Board	50,000–150,000	200
Recycled Cotton Batt	2,000–6,000	30

Other Project Files

This repository also includes design files for a 3D-printable metadiffuser acoustic panel:

• metadiffuser_tile.scad — OpenSCAD parametric design (160x160x25mm tile)
• METADIFFUSER_README.md — Metadiffuser design documentation
• THEORY.md — Acoustic theory background (Helmholtz resonators, dispersion, TMM)
• ASSEMBLY.md — Assembly, mounting, and testing instructions
• QUICKSTART.md / FEDORA_QUICKSTART.md — Quick start guides
• build.sh — STL generation script (headless OpenSCAD)

References

• Cox, T.J. & D'Antonio, P. (2009). Acoustic Absorbers and Diffusers
• Allard, J.F. & Atalla, N. (2009). Propagation of Sound in Porous Media
• Kuttruff, H. (2009). Room Acoustics
• Kinsler, L.E. et al. (2000). Fundamentals of Acoustics
• Jiménez, N. et al. (2017). Metadiffusers: Deep-subwavelength sound diffusers. Scientific Reports, 7, 5389.

License

This project is licensed under the GNU Affero General Public License v3.0 (AGPL-3.0).