Room Modes in a 12x19 ft Room with a 10 ft Ceiling

Mode spectrum

Each line is one standing wave. Axial modes, the strongest kind, stand tallest; tight bunches and wide empty stretches are where the bass will sound uneven.

Axial modes by dimension

What this means for your room

• The lowest room mode is 29.6 Hz, set by the 19 ft length.
• Between 29.6 Hz and 46.9 Hz there are no modes at all, so notes in that 17.3 Hz gap will sound thinner than the bass around them.
• Mode density drops in the 40 Hz third-octave band (0 modes against 1 in the band below), so bass will sound uneven from note to note.
• The proportions (1 : 1.20 : 1.90) fall outside the Bolt area because the room is long and narrow for its height, so modes bunch up along the length.
• Below about 157 Hz (the Schroeder frequency) individual modes shape the sound; above it, reflections and reverb matter more.

Between 29.6 Hz and 46.9 Hz there is no mode to reinforce anything, a gap of 17.3 Hz. Notes that fall in that gap sound thinner and quieter than notes just above or below it.

If you use this room for movies, that gap tends to show up as boom on specific low-frequency effects rather than an even rumble. If it is a music or mixing room, that same spot makes some bass notes read louder on playback than they actually are on the recording, which makes mixing bass by ear risky here.

This room's ratio (1 : 1.20 : 1.90) is outside the Bolt area: the room is long and narrow for its height, which bunches modes up along the length. Treatment can still get it sounding good, but the shape is not helping as much as it could.

How to fix it, in order

1. Put your first traps in the four vertical corners where floor meets ceiling; that is where every mode in this room reaches its loudest point.
2. At 40.0 Hz the quarter wavelength is about 7 ft, deeper than any practical panel, so a porous trap alone will not fully absorb that note. Build corner traps as thick as you can fit (6 to 12 in, straddling the corner with an air gap behind) to take the edge off, then handle the note itself with a membrane or pressure trap tuned near it, careful seat position, and more than one subwoofer with EQ.
3. Avoid the exact middle of the 19 ft length for your seat or mix position; try around 7.2 ft from the front wall (38% of the length) as a starting point, then nudge from there by ear.
4. Test more than one subwoofer position. Corner placement drives the most output but also the least even bass; moving it along a wall or using two subs at different spots tends to average out this room’s peaks.
5. Confirm the fix with an REW measurement at the listening position, paying closest attention below 157 Hz; above that, general room reverb matters more than any single mode.

Every mode below 200 Hz

The table below lists every mode under 200 Hz for this room: 84 in all, 13 axial, 40 tangential and 31 oblique. Axial modes bounce between just two parallel surfaces (say, the two side walls) and are the loudest and most audible; tangential modes involve four surfaces and are quieter; oblique modes bounce off all six surfaces and are the faintest. Start with the axial rows; they cause most of the boomy or thin spots you will actually hear.

Questions about 12x19 rooms

Will a 12x19 room work for a home theater?

This size suits a bedroom theater or dedicated music room, though the 68/100 modal score signals some work ahead, mainly because there is a gap of 17.3 Hz between 29.6 Hz and 46.9 Hz with no mode in between.

Where should I put bass traps in a 12x19 room?

Start in the four floor-to-ceiling corners; every mode in this room peaks there. The 40.0 Hz mode itself would need about 7 ft of depth to fully absorb, more than any panel can give, so build corner traps as thick as you can fit (6 to 12 in) and pair them with a membrane trap tuned near 40.0 Hz.

What subwoofer size is right for a 12 by 19 ft room?

There is no fixed sub size tied to 228 sq ft; that number mostly sets this room's mode frequencies (84 of them under 200 Hz). At this size you will want more headroom than a small room needs, and two subwoofers usually beat one at keeping bass even from seat to seat.

Why does my 12x19 room have weak bass notes?

The short answer for this room: there is a gap of 17.3 Hz between 29.6 Hz and 46.9 Hz with no mode in between. Bass unevenness like that is built into the shape of the room and shows up regardless of what speakers or sub you use.

How do I fix bass problems in a 12x19 room?

Put bass traps in the four floor-to-ceiling corners first, as thick as you can fit (6 to 12 in) plus a membrane trap tuned near 40.0 Hz, since that note's own quarter wavelength (about 7 ft) is too deep for any panel. From there, move your seat to about 7.2 ft from the front wall, then measure with REW below 157 Hz to see what still needs work.

Similar room sizes

• 12x18 ft, 10 ft ceiling
• 12x20 ft, 10 ft ceiling
• 12x19 ft, 8 ft ceiling
• 12x19 ft, 9 ft ceiling