Calculate the standing waves and resonant frequencies in your room. Works with any room shape — not just rectangles.
Free room analysis — no account needed
Room modes are resonant frequencies caused by sound waves reflecting between parallel surfaces. At these frequencies, the reflected waves align to create standing wave patterns with fixed areas of high pressure (peaks) and low pressure (nulls). Every room has three types of modes: axial (between two parallel surfaces), tangential (involving four surfaces), and oblique (involving all six surfaces). Axial modes are the strongest and most problematic for bass reproduction.
Most room mode calculators use the simple formula f = (c/2) × √((n₁/L)² + (n₂/W)² + (n₃/H)²), which only works for rectangular rooms. Atuund uses finite element method (FEM) analysis to compute modes for any room geometry — L-shaped rooms, rooms with alcoves, angled walls, and other irregular shapes. The FEM solver meshes your room into thousands of elements and solves the acoustic wave equation numerically.
Once you know your room modes, the most effective solution is strategic speaker and listener placement. Positioning speakers and your listening seat away from mode pressure maxima reduces excitation of problematic frequencies. Bass traps at room boundaries can also absorb low-frequency energy, though placement matters significantly more than most people realize.
For rectangular rooms, modes can be calculated analytically using the room dimensions and the speed of sound. For non-rectangular rooms, Atuund uses finite element analysis (FEM) — the room is divided into a 3D mesh of tetrahedral elements, and the acoustic eigenvalue problem is solved numerically to find resonant frequencies and their spatial patterns.
Room modes are most significant below 200–300 Hz, where wavelengths are comparable to room dimensions. Above this range (the Schroeder frequency), modes overlap so densely that the room behaves more diffusely. Atuund analyzes modes from 20 Hz to 200 Hz, covering the critical bass region where placement has the most impact.
Yes. Rooms where dimensions are multiples of each other (e.g., 10×20×10 ft) concentrate modes at the same frequencies, creating severe peaks. Ratios like 1:1.26:1.59 (Bolt area) spread modes more evenly. But even in a poorly-proportioned room, optimized speaker placement can dramatically improve the frequency response.
Atuund uses finite element method (FEM) modal analysis to model room acoustics. Built for hi-fi enthusiasts, home theater builders, and anyone who wants better sound from their speakers.