Free Tool

Room Mode & Bass Trap Calculator

Map every standing-wave resonance in your room. The bass-response chart shows where peaks and dips actually fall; the pressure map shows where to sit and where to put traps; the problem panel calls out the few modes that actually matter. Live, interactive, with audible sine playback for each mode.

My rooms

Save room configurations here. Useful when you're comparing rooms, planning treatment, or auditioning a new place.

Room-quality score - Ratio quality + mode spacing + density.
Worst issue
- -
Room
Volume-
Schroeder-
Modes to 300 Hz-

Dimensions

room
m
m
m
Unit

Compare to a textbook-good ratio

Conditions

tune
s

Treated room: 0.25-0.4 s. Living room: 0.5-0.7 s. Untreated bedroom: 0.4-0.6 s.

Quick RT60 presets
°C

Affects speed of sound (343 m/s at 20 °C). Shifts every mode about 0.18 % per °C.

Positions

seat

Positions are fractions of room length (xL) and width (xW) (0 = front-left wall, 1 = back-right). The pressure map below uses these to mark your seat and speakers; the "Seat sits on" stat tells you if you're parked on a peak or null at the worst mode.

xL
xW
xL
xW spread
Seat sits on -

Bass response: every mode below 300 Hz

live

Each spike is a single standing-wave mode at its resonant frequency. Tall red spikes are axial modes (the strongest); orange are tangential; yellow are oblique. When several spikes stack within a few Hz of each other you get an audible boom at that frequency. Above the Schroeder line the modes pack densely enough to smooth into reverb.

Pressure map: first axial mode

Top view (Length x Width)
Side view (Length x Height)

Modes that actually matter

below schroeder

Only the modes below your Schroeder frequency are audible as discrete bumps - everything higher merges into reverb. These are the ones to treat. Press play to hear what each mode actually sounds like in your room.

Show every mode in your room

How room modes work, in three minutes

The three mode types

Axial (strongest, 0 dB relative): one dimension. The first axial mode in a 5 m room is at 343 / (2 x 5) = 34.3 Hz. Most audible, hardest to treat.

Tangential (-3 dB): two dimensions at once. Less energy than axial but still audible.

Oblique (-6 dB): all three dimensions. At higher frequencies these merge into smooth reverb.

The bass-response chart above shows the type of every mode as colour; the spike height is the relative contribution.

Schroeder, treatment, placement

Above the Schroeder frequency, modes are dense enough that the response is statistically smooth. Below it, individual modes dominate and must be addressed.

Three treatments, in order of effort: move the listener off the node/antinode hot-spots the pressure map shows; move the speakers away from walls (corners excite every axial mode at once); add bass traps in the corners (where every axial mode's antinode coincides).

The room-quality score above combines ratio quality, mode spacing, and mode density into one 0-100 number, a quick proxy for how friendly the room is to bass before any treatment.

First-order axial mode by typical room dimension

Fundamental axial mode sits at f = c / (2 x dim). Below the Schroeder frequency, this mode and its harmonics define your bass response - change the dimension, change the music.

Dimension1st2nd3rdWhat it bumps
2.4 m / 8 ft (low ceiling)71 Hz143 Hz214 HzMale vocal fundamentals - boxy "in-the-room" voice.
2.7 m / 9 ft (typical ceiling)64 Hz127 Hz191 HzBass-guitar harmonics warm.
3 m / 10 ft57 Hz114 Hz172 HzKick body, double-bass overtones.
3.5 m49 Hz98 Hz147 HzPipe organ / synth bass fundamentals.
4.2 m (typical width)41 Hz82 Hz122 HzBass-guitar low E exactly - boomy.
5 m34 Hz69 Hz103 HzSub-bass. Pipe organ pedals.
5.5 m (typical length)31 Hz62 Hz94 Hz5-string bass low B (31 Hz) sits on the mode.
6.5 m26 Hz53 Hz79 HzSub-bass; floor-to-ceiling traps still required.

FAQ

Room modes and bass treatment FAQ.

What standing waves do to bass response, how to find them, and the three ways to fix them in real listening rooms.

  1. What are room modes and why do they matter?

    Room modes are standing-wave resonances that build up at specific frequencies determined by your room dimensions. They cause uneven bass: a 30 dB peak at one frequency and a null at another, sometimes in the same listening position. They are the single biggest reason a great speaker can sound bad in a small room.

  2. How do I calculate room modes for my listening room?

    Enter your room length, width, and height in meters or feet. The tool calculates every axial (1D), tangential (2D), and oblique (3D) mode below 300 Hz, the most audible range. The visualizer maps pressure nodes (quiet zones) and antinodes (loud zones) so you can see where bass peaks and dead spots will be.

  3. How do I treat room modes once I find them?

    Three approaches: (1) Move the listening position to a node-free spot the tool highlights. (2) Move the speakers: corners excite all modes, away-from-walls excites fewer. (3) Add bass traps at the room corners and rear wall to absorb the worst peaks. Most rooms benefit from all three.

  4. What room dimensions are best for music listening?

    Avoid square rooms or rooms with two equal dimensions. They stack modes at the same frequencies and create huge peaks. Golden ratio proportions (roughly 1 : 1.618 : 2.618) spread modes evenly across the spectrum. The calculator visualizes mode density so you can compare different aspect ratios for your build.