Acoustic Room Mode Analyzer

Find axial, tangential, and oblique standing-wave modes for a rectangular room, flag problematic low-frequency resonances, and check recommended room ratios.

Room Geometry

Room Mode Results

Fundamental Axial Modes

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Hz along Lx / Ly / Lz

Flagged in Problem Range

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modes below display cutoff

Modal Density Estimate

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modes / Hz at 200 Hz

Room Volume

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cubic units

# Mode Type Indices (nx, ny, nz) Frequency (Hz) Status

Recommended Room Ratios (Bolt Area & Common Standards)

Ratios are scaled so the smallest recommended dimension equals the current shortest side. Well-spread ratios avoid coincident (clustered) modes.

Standard Ratio (H : W : L) Recommended Dims (current units) Match

Formula Breakdown

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Informative Guides & Helper Articles

How to Use the Acoustic Room Mode Analyzer

Computes axial, tangential, and oblique room modes, flags problem frequencies, and checks Bolt-area room ratios.

  1. Enter room dimensions (L x W x H).
  2. Read the mode map: axial modes dominate; stacked modes below 300 Hz are the booms.
  3. Check the Bolt ratio for room proportion quality.

Room Modes: f = c/2L

Axial mode f = c/2L | modes matter < 300 Hz

Axial modes (strongest) resonate at f = c/2L - with c ~343 m/s, a 4.57 m room length modes at ~37.5 Hz and its multiples; width and height add series, and coincident series stack into boom-or-dead spots. Below ~300 Hz is modal territory where treatment is positioning, not foam: moving speakers and listener off mode extremes (the 38% rule for listener depth is the classic start) fixes what EQ cannot. Bolt ratios identify proportions that spread modes evenly - cubes are worst because every axis modes identically.

Acoustic Room Mode Analyzer FAQ

Why does my room boom at certain notes?

Standing waves: dimensions resonate at f=c/2L and multiples. Coincident modes from different axes stack.

What is a Bolt ratio?

A room-proportion check: dimensions that spread modes evenly. Avoid cubes and 1:2 integer ratios.

Can EQ fix room modes?

No - nulls cannot be boosted back. Move speakers/listener off extremes first, treat corners second.