Ask how to fix boomy bass on any forum and the answer is usually "buy bass traps." It's good advice, but in a small room it's a bigger job than it sounds, and a lot of what's sold as bass trapping barely touches bass.
What bass traps do
A bass trap soaks up low notes so they can't build up and ring on. Low notes are long waves, so the trap has to be thick to catch them. Real bass traps are at least 10 cm (4 in) deep, usually more, and made of dense mineral wool or fiberglass. Many sit across a corner, which makes them deeper still.
They work best in corners because every room's booms are loudest there, where the walls meet each other and the floor or ceiling. A trap in a corner catches more of the boom than the same trap in the middle of a wall.
Why foam panels don't count
The thin foam tiles sold for studios, usually 2 to 5 cm (1 to 2 in) thick, soak up echo and high frequencies. Bass goes straight through them. The small foam blocks sold as corner bass traps help a little with the upper bass and do almost nothing for the deepest booms.
Foam still has a job: it calms the echo off bare walls, which helps you hear detail and judge reverb.
How many a small room needs
More than most people expect. Start with the corners behind your monitors, floor to ceiling, then the corners behind you, then the edges where the walls meet the ceiling. In a small room, a handful of traps usually makes the boom smaller and shorter without making it go away.
That costs money and takes room. In a rented place you may not be allowed to screw panels into the walls, and freestanding traps eat floor space a small room can't spare.
In a rented room
You don't need to drill. Freestanding bass traps stand in a corner on their own feet, and panels can lean against a wall or hang from removable hooks. Put the first ones in the corners behind your monitors, as you would in a room you own.
What traps can't do
Traps change the room itself, so they help wherever you sit and whatever you play. In a small room, though, they rarely remove a boom completely. The note still stands out at your seat, just less, and it fades faster.
Placement still comes first. If you sit where one note piles up, moving your chair often does more for that note than another trap would.
Where correction fits
Correction works at your seat instead of in the room. Unboom finds the bass note your room exaggerates where you sit, then gently turns just that note down in your music and video apps, and on a Mac in your DAW through its plug-in. It takes a couple of minutes and leaves the room as it is.
It doesn't change the room, so it can't calm echo, and it never boosts, so it won't fill a note your room cancels.
The two work well together. Traps improve the room for everything you play, and correction tames the note that's still too loud. If you can't add traps yet, correction is the quickest way to deal with the boom in the meantime.
A plan for most small rooms
- Move your chair and monitors first. It's free, and the Monitor Placement tool gives you a starting point.
- Find the boom from your seat with the free Boom Finder.
- Turn that note down with Unboom, or with a narrow EQ cut if you only need it in one DAW.
- Add bass traps in the corners when you can, starting behind your monitors.
- Add rugs, curtains, or foam if echo bothers you.
How do I fix boomy bass in a small room? goes deeper into each step.
FAQ
Bass traps or acoustic panels first?
For boomy bass, bass traps. Panels mostly help with echo, which is a different problem.
How thick should a bass trap be?
At least 10 cm (4 in). Thicker traps reach lower notes, and a gap between the trap and the wall helps them reach lower still.
Can I build my own bass traps?
Yes. Many people build wooden frames filled with thick mineral wool or fiberglass and wrap them in fabric. Wear gloves and a mask while you cut the insulation.
Do bass traps help the notes that vanish?
A little. By calming the booms, they make the dips at your seat milder too. Moving your chair usually changes a dip more.