Where to Put Bass Traps – Quick & Easy Guide (for Dummies)

Where to put bass trapsWhere to put bass traps… if you’re building a home studio for recording or mixing, and especially for the first time, this would be your foremost room treatment concern.

You could always find ways to treat your recording or control room environment to be sufficiently or absolutely dry. But in the final analysis, getting control of the way low frequencies behave in your room is going to make the greater portion of the difference in the way you hear your audio.

Once you’ve sufficiently tamed the bass frequencies in your room, you can take care of the how much wet/dry sound you want in your studio, using studio foam panels or diffusers.

So in this guide, we’ll be focusing on the first question you should be asking when seeking to acoustically treat your room: How do you mount your bass traps?

Let’s take a closer look…


Table of Content


Where to Put Bass Traps

(The short answer)

You want to put your bass traps in the corners of the room, particularly the trihedral corners first (wall-wall-ceiling/floor), and if you can, add bass traps to the dihedral corners (wall-wall/ceiling) for progressively improved results.trihedral and dihedral corner bass traps

If you want the more detailed and explained answer, you can jump to here, or…

… to get a better understanding about bass traps, how they work, and how to mount them in your room intelligently, let’s cover some basic yet important knowledge first. (recommended: Keep reading…)

What are Bass Traps

Bass traps are low frequency absorbers that minimize the bass resonance in a room. The reason why we call them bass traps is because, as the name suggests, they absorb the bass frequencies in your room, especially in places where the low frequencies tend to build up an gather the most, causing the greatest frequency resonance (ie, the corners, especially the trihedral corners).

There are two main types of bass traps for you to choose from: resonant absorbers, or porous absorbers. And there are two types of either absorbers as well.

We will talk about these various types of absorbers and bass traps in a minute, as they all have their specific benefits and disadvantages. But before we continue, let’s talk a little science behind why it’s important to tame the low end frequencies of your room.

Why Low End Control is Important

Bass traps are especially crucial for small to medium-sized studios, as low frequencies have much longer wavelengths than high frequencies, spanning a longer distance.

Since the reflective surfaces (walls, ceiling) of a smaller or mid-sized room are relatively short in distance from each other, the amount of resonance (or build up) of these longer frequencies can accumulate and lead to some nasty results. Like single-note bass lines where each bass note in a track sounds the same, or lower frequencies masking the rest of the audio.

Sizing up sound

Like I mentioned, low frequencies are longer than high frequencies. For instance, the low E on a guitar string is 82 Hz, and the wave length of that frequency is 13.7 feet. In a large room, that frequency would have had time to cycle through and lose energy before reaching a reflective surface. But in a small room, that low E note could’ve hit a reflective surface and attempt to “double back” on itself before losing sufficient energy. That doubling back, or reflection, results in a resonance that gives the impression of a different note, or different notes. And what does this mean for your mix? A lot of mess and confusion in what frequencies you think you’ll be hearing.

Ideally, the perfect room for proper bass response is a large room. In a large room, like a concert hall, cathedral, or television studio, the fundamental resonance of the room is very low, giving you a more uniform frequency response across the board. These kinds of rooms not only provide excellent bass response, but also natural sounding reverb.

But more than likely, you are thinking about adding some acoustic treatment to a room that’s quite small to medium in size. And for that reason, controlling the bass response in your room will be of high priority to you. Whereafter you can treat your room for proper dryness (via acoustic panels and diffusers) as you like, and add reverb via professional plugins during the mixing stage of your music production.

Types of Bass Traps

Now that we’ve gotten some fundamental theory out of the way, let’s look into what sort of bass traps we have out there, and which ones are the best to choose from. Then we’ll look at where to put bass traps based on what you want to go with.

Porous Absorbers

Porous absorbers
Common types of porous absorbers

Also called Frictional or Velocity Absorbers, these are by far the most common when it comes to getting good bass traps. Mostly because they are the cheapest and most “DIY-friendly” bass traps out there. Not just that, they also are effective at minimizing the higher and mid frequencies as well, potentially giving your room a dryer sound in the process.

The velocity factor

There are two ways that you can “trap” low end frequencies: You can absorb the velocity of the wave, or your can absorb its pressure as it meets a reflective surface.

Porous absorbers act on absorbing the velocity portion of the wave before it reaches the reflective surface, therefore neutralizing any resonance build up. It does this by capturing and slowing down the air molecules at their highest velocity, where the bass energy is highest.

For this reason, porous absorbers tend to take up the most space in a room — in order to absorb troublesome sound waves, you’d need to capture them where they are at their highest velocity. If your troublesome frequency, then, tends to be around 200 Hz, then using the quarter wavelength rule, you’d calculate the distance where 200 Hz is at its highest velocity to be at 1.4 feet (0.43 meters)

Quick Formula

Empirical units: ¼ Wavelength = ¼ (1125 / Hz) = Distance in feet

or

Metric units: ¼ Wavelength = ¼ (343 / Hz) = Distance in meters

So in order for porous absorbers to be properly effective, they need to be either quite thick, or be placed at a distance from the corner.

Effective control

For this reason, it would either mean you’d need to know how to calculate your precise room mode and determine its natural resonance and where your troublesome frequencies are…

… or, do as most studio owners do:

Go by way of experimenting until you hear the best results.

The latter is most likely the best way, since even if you were to calculate your precise room mode, it would still be affected by things like the objects in your room, to the way the room responds to your studio monitors and how they are placed.

Quick Tip:

Keep in mind that the lower the bass frequency you want to “trap,” the thicker the absorber or further away from the reflective surface your porous absorber will be.

Bottomline

Porous absorbers are great choices that, while requires some experimentation, is the easiest to setup without getting professional advice.

Porous Absorbers Pros & Cons

+ Pros

  • Easiest to get
  • Most “DIY” solution
  • Cheapest option

— Cons

  • Requires experimentation to “get right”
  • Takes up the most space (“padding”)
  • Not as effective on low end frequencies as resonant absorbers

Now, there are actually two types of porous absorbers out there. But before we get to that, let’s talk about another common type of bass trap I just hinted at. One that’s used for more troublesome listening rooms, or high-end studios.

Resonant Absorbers

Also called “Pressure absorbers” is probably the most accurate choice for a small to medium sized room. Unlike porous absorbers, they don’t slow down the velocity of low frequency bass, but rather absorb the pressure right up against a boundary, like a wall.

They’re built specifically for bass frequencies, so they’re the most effective solution and get right to the problem: neutralizing low end frequencies where pressure is highest. Porous absorbers on the other hand, can be use in a broadband manner to help keep a room dry, but sometimes be less effect in taming bass frequencies.

This specific use is what makes resonant absorbers an ideal option. However, they are harder to set up because you’d need a professional to diagnose the acoustics of your room and set up specialized resonant absorbers for the way your room treats bass frequencies.

For this reason, resonant pressure absorbers are also called “tuned absorbers,” since they are “tuned” to specific rooms, and work on a room-to-room basis. Whereas, the porous absorbers above can either be bought as mass produced items, or made yourself using special materials.

Furthermore, there are two types or resonant absorbers: Helmholtz Resonators, and Diaphragmatic Absorbers.

Helmholtz resonators

These are one of the most complex bass traps you can get. They work by capturing bass frequencies in an air-tight cavity through small portholes.

A helmholtz resonator for bass trap
A helmholtz resonator for bass trap trap (source).

Diaphragmatic absorbers

These will be found in some of the more advanced studios. They consist of a membrane diaphragm that absorbs the pressure of the bass frequencies right up against the reflective surface.

Diaphragmatic absorber
A diaphragmatic absorber in several layers (source).

Resonant Absorbers Pros & Cons

+ Pros

  • Most accurate bass absorption available
  • Takes up little room

— Cons

  • Requires expert diagnosis and installation
  • More expensive option
  • Only suitable on a room-to-room basis

What Bass Traps to Get

Well, now you may be wondering which bass traps to get.

My advice would be to get porous absorbers first. They are the easiest to purchase, though they would require some experimentation, but they should cover whatever you need.

But if you still have bass trapping issues, and you have the budget for it, you can implement resonant absorbers with the help of an expert.

Either way, the combination or resonant and porous absorbers work very well, as the porous absorbers will cover the wet portion of your room’s acoustics while resonant absorbers will clean up the stubborn bass mess where porous absorbers may fail.

Which Porous Absorber to Get

That said, we get back to this question. Your choice is really narrowed down to only two choices of porous absorbers:

1. Studio Foam Corner Bass Traps – These are thick triangular bass traps that you can mount in the corners.

Studio Foam Corner Bass Traps

2. Studio Panel Corner Bass Traps – These are flat acoustic panels that you mount in the corners, providing you with a “gap” to absorb low frequency build up.

Studio Panel Corner Bass Traps

Either of these options are fine, and you can make them yourself out of foam or fibrous materials, or buy them online or at your local store.

How Many Bass Traps Do You Need

Bass builds up mostly in the corners of a room. So if we count the corners of a typical rectangular shaped room, we have 20 corners…

But this question is easier answered by going back to the original subject of this article…

Where To Put Bass Traps

Since low frequencies tend to accumulate more resonance in the corners, then it would make sense to mount bass traps in all corners of your room… right?

Minimalist Setup

Well, before you run off doing so, recall that the most essential corners are the trihedral corners (wall-wall-ceiling and wall-wall-floor intersections). Anything beyond that is just progressive improvement. But if you leave these essential trihedral corners out, then you’re unlikely to see any improvement at all in your low frequency response.

However, if you still need to budget for less, mount your bass traps in the upper corners only.

trihedral corners

Most Ideal Bass Trap Setup

Surely, you may be wondering what’s the best and most ideal bass trap setup for your room.

If you can get bass traps mounted on all the trihedral corners, the next thing you should think about is adding bass traps to the dihedral corners (wall-wall/ceiling).

ideal positions for bass traps in trihedral and dihedral corners
You can leave out the floor dihedral corners to maximize space

Start with vertical bass traps, in the corners where the walls meet each other.

After that, you can add horizontal bass traps, in the corners where the walls meets the ceiling.

And that is it 🙂

Want to know the science behind it? Go back here.


Final Thoughts

Coming up with an effective low frequency control strategy for your room can seem little daunting for the uninitiated. But with this post, I hopefully shed some light on the matter, and helped to simplify the process, while clarifying the necessity for bass traps, and adding just a little of the science behind how low frequency control works in a room.

I hope you found this article useful. If you have any comments please leave them down below… and feel free to let myself and other readers know what your thoughts are on the best way to effectively mount bass traps in a room.

And remember, if you know anyone else that would find this information useful, please feel free to share this with them or with your friends on social media.

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