How to Treat a Room for Mixing on a Budget

To learn how to treat a room for mixing, start with the problems, not the products: find your room's worst bass frequencies, set up your speakers and chair symmetrically, absorb the first reflections, and put the thickest material you can afford in the corners. Most of it can be done on a budget with rugs, blankets, bookshelves and homemade panels.

What does acoustic treatment actually do?

Acoustic treatment reduces reflections and resonances inside a room, so what you hear at the mix position is closer to what your speakers actually play.

• Acoustic treatment: absorbers, diffusers and bass traps that control echoes and resonances inside the room.
• Soundproofing (isolation): mass, airtight seals and decoupled construction that stop sound getting in or out. Foam and rugs do almost nothing here.

Andrew Scheps, award-winning mixer, producer and Campus mentor (Beyoncé, Lana Del Rey, Red Hot Chili Peppers), is clear that this does not require a big budget. In a free Core Audio Program info session, he described part of the program this way:

"there's a lot of stuff in the course that is the complete opposite of that. You want to treat your room, go get some hallway rugs and stick them on the wall. And here's how you can think about that. And so ways to really do stuff in the sort of budget that you have."

What are room modes, and why do they ruin the low end?

Room modes are resonances, or standing waves, that build up between surfaces at frequencies set by the room's dimensions. They make some bass notes boom and others nearly vanish, depending on where you sit.

Scheps gives the one-line definition: "anything that has acoustic energy in it has a resonant frequency. And that resonant frequency is defined by the dimensions of the room." Most home studios are rectangular, with "lots of parallel surfaces, which sonically is bad, but it actually makes it really easy to figure out, well, what are the problem frequencies in your room?"

Axial modes bounce between two opposite surfaces and are the strongest. Tangential modes involve four surfaces, oblique modes all six. As Scheps puts it, the axial mode is "basically a one dimensional standing wave. Tangential is two dimensional oblique is three dimensional."

Small rooms struggle because bass wavelengths are huge. The low E on a bass guitar, about 41 Hz, has a wavelength of roughly 8.3 m (27 ft), longer than most home studios. Scheps uses that low E in the session to explain why you often cannot hear the low end properly in a small room. If wavelength and frequency are new to you, start with our guide to audio engineering fundamentals.

How do you calculate your room modes?

For axial modes, use f = c / 2L, where c is the speed of sound (about 343 m/s, or 1,130 ft/s) and L is the distance between two opposite surfaces. Whole-number multiples (2f, 3f, 4f) are modes too. Here is a 4 m × 3 m × 2.4 m room, about 13 × 10 × 8 ft:

Look for modes that stack up. Here, length and width both land on 171.5 Hz, so expect that area to ring. Wide gaps, like 42.9 to 57.2 Hz, tend to sound thin or uneven.

Scheps works through this math, from standing waves to sweeping a real room, in the acoustics course of the Core Audio Program. In his words, "we go from total geekdom into super practical stuff as quickly as possible."

Where should you put your speakers and listening position?

Set up symmetrically along the room's length, with the speakers and your head forming an equilateral triangle, and start with your ears at about 38% of the room's length from the front wall. Positioning is free, so do it first.

1. Face the long dimension: speakers on a short wall, firing down the length.
2. Center between the side walls, so both speakers get the same reflections.
3. Build an equilateral triangle between the two speakers and your head, with tweeters at ear height.
4. Try the 38% rule. In a 4 m room, that puts your head about 1.5 m from the front wall. It is a starting point: it keeps you away from the room's center, where the first length mode leaves a hole in the bass, and from the back wall, where bass piles up.
5. Mind the wall behind the speakers. Its reflection causes a dip near c / 4d, where d is the speaker-to-wall distance. At 0.5 m, that is around 170 Hz.

How do you treat first reflection points?

First reflection points are the spots on the side walls, ceiling, desk and floor where sound from each speaker bounces once before reaching your ears. Absorbing them sharpens the stereo image.

To find them, sit at the mix position while a friend slides a mirror along the side wall. Wherever you can see a speaker in the mirror, mark the wall. Repeat on the other side and the ceiling. Then put absorption at the marks, hang a panel above the space between you and the speakers, and lay a thick rug on the floor in front of the desk.

This is where hallway rugs, blankets and curtains earn their place. They will not touch the bass, but they tame the reflections that blur your imaging.

How do you treat a room for mixing on a budget?

Work in this order: positioning, first reflections, bass traps in the corners, then everything else.

Why do bass traps go in the corners?

Every room mode has a pressure maximum at the room's boundaries, and corners are where several boundaries meet, so bass energy collects there. Porous absorbers need depth to reach low frequencies, so use thick material or mount panels with an air gap behind them. Do the front corners first, then the back corners, then the wall-to-ceiling corners. If you build panels from mineral wool or fiberglass, wear gloves and a mask and wrap them fully in breathable fabric.

The classic budget mistake is covering every wall in thin foam or blankets: the highs disappear, the bass problems stay, and you mix too bright to compensate.

How do you find the worst frequencies in your room?

Play a slow sine sweep or individual sine tones through your speakers and listen at the mix position. The notes that jump out or vanish are your room modes at work.

"you could sweep your room and say, wow, yeah, that frequency is crazy in here. And it's different everywhere I stand in the room. So now you know when you're treating your room, this is sort of the frequency range I should concentrate on the most. And you'll find the three or four worst frequencies in a room."

A measurement microphone and room-measurement software show the same thing as a graph. Room-correction EQ can tame peaks, but it cannot fill a null or shorten how long a bass note rings. Treat first, correct second.

Practice exercise: map your room in 30 minutes

You need a tape measure, a calculator and a sine generator in your DAW.

1. Measure your room's length, width and height.
2. Calculate the first three axial modes per dimension with f = c / 2L. Circle any within a few hertz of each other.
3. Set a safe level with a 100 Hz tone. Keep it moderate; sine tones are tiring.
4. Play each frequency from the mix position. Note which are loudest and which almost disappear.
5. Move your chair 10 cm (4 in) at a time and replay your worst frequencies. Keep the most even spot.
6. Write down your three or four worst frequencies. They show where bass traps matter most and which notes to distrust while mixing.

Even after treatment, compare your mixes with commercial songs you know well. Our guide to using reference tracks for mixing shows how they help you work around your room.

Frequently asked questions

Can you mix in an untreated room?

Yes, but you will be guessing in the low end. An untreated small room has strong room modes and early reflections that change what you hear, so mixes often translate poorly. Start with free fixes: a symmetric setup, speakers on a short wall and the listening position at about 38% of the room's length. Then check mixes on headphones and other systems, and compare with reference tracks.

Does acoustic foam work for mixing rooms?

Thin acoustic foam absorbs high and upper-mid frequencies, so it can help with flutter echo and first reflections. It does very little for bass, which is where small rooms have their biggest problems. Covering a room in thin foam often makes it sound dull while the low end stays uneven. Thick mineral wool or fiberglass panels and corner bass traps cover a much wider range.

What is the 38% rule in studio acoustics?

The 38% rule suggests placing your listening position about 38% of the room's length from the front wall. It keeps you away from the center of the room, where the first length mode cancels, and from the back wall, where bass builds up. Treat it as a starting point and fine-tune by moving your chair in small steps while listening to familiar music.

Where should bass traps go first?

Put bass traps in the front corners first, near your speakers, then the back corners, then the corners where walls meet the ceiling. Corners are where pressure from many room modes builds up, so thick absorbers there have the most effect. Depth matters for bass: thin panels mostly absorb mids and highs, whatever the label says.

Room acoustics makes sense once you understand how sound behaves. Andrew Scheps teaches it in the Core Audio Program, a four-course, on-demand program for all levels whose second course, The Nature of Sound, covers wave physics, acoustics and how we hear, with a teaching assistant and a 14-day money-back guarantee. To hear Scheps explain room modes himself, the full info session is free on Campus Replays.