STEREOLABSL-1400
MOD-01ACOUSTIC MODESPAGE 1 OF 14

Room Axial Standing Wave Modes

Calculate 1st–4th order standing wave resonances, modal pile-ups, Schroeder transition frequency, and Bolt room ratios.

OSC-1: 440 Hz
BENCH PRESETS:
UNITMeasurement System
DIM-L
2 m1st Axial: 31.8 Hz15 m
DIM-W
2 m1st Axial: 38.2 Hz12 m
DIM-H
1.8 m1st Axial: 61.3 Hz6 m
TEMP
5 °Cc = 343.4 m/s35 °C
AXIAL STANDING WAVE SPECTRUM (20 Hz – 250 Hz)
Length (L) Width (W) Height (H)
20Hz50Hz80Hz110Hz140Hz170Hz200Hz230Hz250Hzf_Schroeder (137Hz)L1W1H1L2W2L3W3H2L4W4H3H4
L-AXIS PRESSURE MAP (1× HALF-WAVE)
SELECTED RESONANCE INSPECTOR (TAP SPIKES ABOVE)
Mode L1— 31.8 Hz(λ = 10.80m)

Bright bands show high-pressure antinodes (boomy zones); dark bands show pressure nulls (cancellations).

MODAL PILE-UP WARNING (1 COLLISIONS): H1/L2 near 61Hz (Δ2.3Hz) — Expect bass booming at these frequencies.
L1 Fundamental
31.8Hz
2nd: 63.6 Hz
W1 Fundamental
38.2Hz
2nd: 76.3 Hz
H1 Fundamental
61.3Hz
2nd: 122.7 Hz
Schroeder Freq
137Hz
Ratio 1:1.61:1.93
TECHNICAL MANUAL // MOD-01 REFERENCE SHEET

How It Works & Acoustic Engineering Principles

#standing waves#bass trap#room ratios#bolt area#schroeder#axial modes
GOVERNING ELECTRO-ACOUSTIC EQUATIONSI / IMPERIAL VERIFIED
f_n = (c / 2) × (n / D) | f_Schroeder ≈ 2000 × √(RT60 / V)
f_nResonant frequency of the n-th harmonic axial mode (Hz)
cSpeed of sound in air (~343 m/s at 20°C / 1125 ft/s)
nMode harmonic order (1 = Fundamental Half-Wave, 2 = Full-Wave, 3, 4...)
DParallel boundary dimension: Length (L), Width (W), or Height (H)

Physical Mechanism & Theory

Below the room’s Schroeder transition frequency (typically 120 Hz – 250 Hz in domestic and studio rooms), sound does not behave like rays bouncing off walls—it behaves like standing electromagnetic waves trapped inside a resonant cavity. Whenever a half-wavelength (λ/2) or any integer multiple fits exactly between two parallel walls, reflected waves lock in phase with incoming waves, creating fixed pressure peaks (antinodes) at the walls and deep cancellations (nodes) inside the room.

Axial modes (between two opposing surfaces) carry the highest acoustic energy—up to 6 dB stronger than tangential (4-wall) or oblique (6-wall) modes. When two or more room dimensions share equal or integer-multiple lengths (such as a cube or a room where Length = 2 × Width), their modal frequencies stack on top of each other ("Modal Pile-Up"), producing severe one-note bass boom and overhang.

Studio Bench Rules of Thumb

  • 01.Avoid integer dimension multiples: Never build or set up a listening room where Length, Width, or Height are identical or simple multiples (e.g., 2.5m ceiling with 5.0m width causes every 2nd width mode to collide with a height mode).
  • 02.Target Golden / Sepmeyer Ratios: Ideal dimensional ratios like Sepmeyer B (1 : 1.28 : 1.54) or Louden (1 : 1.4 : 1.9) distribute low-frequency resonances evenly across the 20–200 Hz spectrum.
  • 03.Pressure Antinodes are at the boundaries: All room modes reach maximum pressure right against the walls and corners, making tri-corners the single most effective location for bass trapping.