3 Effective Acoustic Treatment Plans for Studios

Acoustic treatment is one of the most effective ways to improve the sound of your room for recording, mixing, and critical listening. But creating an acoustic treatment plan can seem complex and intimidating, leading many people never to take action.

I’ll share three simple acoustic treatment plans that you can choose from depending on your budget.

Thanks to GIK Acoustics for sponsoring this content and supporting audio education.

Not only does GIK make great acoustic panels, but they also have educational resources about acoustics on their website. You can get custom advice for how to optimize the acoustics of YOUR room there.


The acoustic treatment strategy you choose will depend on how you intend to use your room. If you know the position of the speakers and the listening position (such as in a mixing room), you can optimize the treatment plan for that scenario.

However, if you only know the position of the speakers but the listening position will change throughout the room (such as a home theater), you’ll have more variables to account for acoustically.

You’ll have even less predictability in a tracking room with various instruments and microphones positioned differently every session.

I’ll assume that you want a room for mixing, producing, and recording audio for music. But, regardless of which type of room you are treating, these tips and examples will be helpful.


Stage 1 – Early Reflections

The first thing I’d recommend addressing with your acoustic treatment plan is the problem of early reflections.

When sound comes out of your speakers, some will go directly to the listening position (this is direct sound). Some sound will reflect off walls, floors, and ceilings before reaching the listening position (this is indirect sound).

Early reflections are the indirect sounds that take the shortest pathways from the speaker to the listener.

In an empty, rectangular room, there are six surfaces: four walls, a ceiling, and a floor. When sound goes outward in all directions from the speaker, it will reflect off of each of these surfaces and back to the listening position.

If these indirect reflections and direct sound from the speakers were all synchronized in time, everything would just get a little louder. However, each indirect pathway is a different distance, creating a scenario where multiple copies of the same signal converge with a slight delay between them, resulting in phase interference and comb filtering.

Now, we don’t necessarily need to treat EVERY bit of surface area in the room to treat these early reflections.

If there is a defined listening position in the room, you can use a mirror along the surface of the walls or ceiling to identify the location of each reflection. Then, it’s as simple as placing an absorptive panel in that position.

For the first stage in my acoustic treatment plan, I’ll be focusing on the side walls and ceiling, placing two Monster Bass Traps on each side and three on the ceiling.

The indirect pathway the sound takes to the rear wall to the listening position is considerably longer than the pathways taken to the side walls or ceiling to the listening position.

This means the side walls and ceiling will result in a shorter time delay than the rear wall and that the reflected sound will be closer in level to the direct sound – and therefore more extreme interference will occur.

As for the front wall, it presents a very short indirect pathway as well. But the directivity of the speakers is such that very little mid- and high-frequency sound will reach the front wall anyway. So, I’ll save treatment of the front and rear walls for later.

One thing that’s important to understand for any stage along this acoustic treatment plan is that you can use any thickness of panel you want (but your results will vary).

A helpful guideline is the ¼-wavelength principle. The thickness of the panel should be at least 25% of the lowest wavelength you wish to absorb.

This is a helpful tool for estimating the effectiveness of a panel based on its depth.

If we enter the thickness of a 7.3-inch Monster Bass Trap and compare it to a 3.6-inch 242 panel, we see that the absorption of the Monster Bass Trap extends down further into the lower frequencies compared to the thinner 242 panel. And if you use an even thinner panel, such as a 1-inch Razor panel, the pattern continues.

This means you will only absorb the highest frequencies when using thin panels. For music, because there is energy throughout the frequency spectrum, this could exacerbate problems in the midrange by absorbing the higher frequencies while just allowing the lower frequencies to reflect.


Stage 2 – Reverb Time

While treating the early reflections will help a lot, there will still be longer reflections off of the remaining untreated surfaces in the room.

These longer reflections will have traveled more distance and will have interacted with more surfaces by the time they reach the listening position. Therefore, absorption throughout the room is not so much a solution for comb filtering but more so an attempt to control the reverberation time within the space.

This can most easily be seen on a waterfall graph, where the time variable is represented to show how long it takes for various frequencies to decay.

We don’t necessarily want or need a room with zero reverb. A natural amount of reverb is ok and is actually preferred by some people for some applications. In fact, an overly dry room can sound unnatural and dark.

Too much reverb in a room can give you an unrealistic understanding of the reverb in a mix and can potentially cause masking problems where the quietest sounds in the mix will be masked by the room’s natural reverb tail.

And if you’re using your room for recording, reverb can make your recordings sound amateur and difficult to mix.

To address these problems, I’m adding in some 5.25-inch 244 panels on the rear half of the room with some 242 panels on the ceiling. I’ll also use some 242 panels to break up the reflections off of the rear wall.

Remember – these panels are not as effective at low frequencies as the Monster Bass Traps, but they are less expensive, they take up less space, and I’ll mostly be recording voice in this half of the room (which has a more limited bandwidth than full-range speakers). It’s just a matter of your budget and the specific goals you have in mind.


Stage 3 – Bass Response

If you’re mixing in a typical bedroom studio, chances are you will have a rectangular room. Depending on the dimensions and materials that make up your room, you will experience room modes where specific frequencies resonate within the space.

Typically, the most concerning room modes are the axial room modes, which occur between two surfaces (front wall-to-rear wall, side wall-to-side wall, or floor-to-ceiling).

For example, the front and back wall of my room theoretically resonate at 45 Hz, 90 Hz, and 135 Hz. At these frequencies, there will be areas of a lot of pressure change and areas of very little pressure change at all.

Remember the ¼-wavelength principle from earlier? This guideline applies to velocity absorbers (sometimes called porous absorbers). All of the panels discussed so far have been porous absorbers.

If we wanted to absorb frequencies down to 135 Hz with a velocity absorber, the panel would need to be 2 feet deep, according to the ¼-wavelength principle. And if we want to absorb 45 Hz with porous absorbers, we will soon have very little space for making music.

Lower frequencies (with longer wavelengths) will require thicker porous absorption panels in order to significantly interfere with the velocity of the air molecules as they oscillate with the sound wave. For the lowest frequencies, this is not practical, so we often use the thickest possible panels we can and accept that we never truly reach perfection.

Putting soffit traps in the corners is a good way to maximize the depth of the panel in two dimensions without sacrificing too much useful space. These 10-inch Sound Blocks on the back wall (with an air gap behind them) are effective for low-frequency absorption, and there is additional help with 6-inch Alpha Panels on the front wall.

This approach attempts to absorb lower frequencies without absorbing too much high-frequency energy.

Alternatively, you can use pressure absorption panels, which operate best in areas of maximum pressure change and minimum velocity. These come in several forms, each tuned to a specific frequency band.

This method allows for much more effective absorption of lower frequencies without as much absorption of higher frequencies, but they are also more difficult to get right due to their custom nature.


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