Acoustic treatment with slats - before-and-after measurements

Recently, I installed some acoustic panels in my listening room of the "slat wall" type, and I took the opportunity to make some before-and-after measurements. I'm posting it here as a service to the community, in case it is of interest.

For some background, I live in an apartment with an L-shaped living room as my listening room. The front wall is plaster/drywall, the back wall is concrete. Open on the left side, windows with curtains on the right side. I have a NAD M33 running Dirac Live. Two subs. The sound was quite good, but I had some issues with reverberation. Also, the speakers and my head are a bit too close to the walls, so there are - I assume - boundary effects in the 100-300 Hz region. This is what I wanted to fix.

Why slats? I first considered conventional acoustic absorbers from RPG, GIK, etc. Maybe mounted behind the speakers and behind the sofa where my listening position is. However, I was troubled by uncertainty about how effective they would be - at least in my use case. Besides, I find this kind of panels extremely ugly... Then somehow I came across slats. You can find a number of these slat panels on the internet, marketed as acoustic panels. Mine are from Fibrotech. The panels are 9 mm thick felt mats with slats in MDF glued on. A test sample I ordered looks like this:


Panels like this don't seem to be much discussed for audiophile purposes compared to conventional absorbers. The few discussions I have seen have been mixed. Anyway, even if they would not be as effective, they cover more wall - and look a lot better. So I figured that even if they would end up doing nothing for the acoustics they would look good enough to be worth it. Here is how my living room looks now:


OK, enough talk, lets see some measurements. Here is a graph of the RT60 before and after (Topt is shown):


The only things that changed from before to after are the wall panels. The position of furniture, mic, etc. are essentially the same. Dirac Live was used with the exact same filters for comparison. As you can see, the region from about 300 Hz and upwards has significantly reduced decay time. Now it doesn't exceed much above 500 ms.

Here is the frequency response (both measurements are volume adjusted to roughly 75 dB on the REW SPL meter):


Unfortunately, the troublesome region from 100-300 Hz is still troublesome, or maybe slightly less so. I'll know more when I get around to re-running Dirac and do the sub integration again from scratch. (The response looks somewhat bass heavy, but actually it doesn't sound as bad as it looks.)

And here are left and right speaker ETC curves:


So how does it sound subjectively? First of all the level of sound is lower. I need to turn up the volume a bit to play at the same perceived level. This makes sense to me, because some sound energy is removed by the absorption. Second, reverberation is perceivably lower. I would subjectively describe it as being "closer to the music" - especially for vocals. This also makes sense, I guess, since reverberation may be associated with large rooms, thereby distance. Finally, I think I can hear more details now, like in drumming and other "rapid impulse bursts". The first two of these effects, I feel certain to pick out in a blind test - the third, I *think* I would, but I don't know.

To conclude, I'm very happy with my new slat wall panels. They look good, and I think they solved at least some of my acoustic problems. They may be slightly less effective than conventional absorbers, but they work. My impression is that they are not highly regarded by audiophiles, but I really don't understand why. I think at least they should be in the toolbox.

OK, that's it. I hope this was useful. To be honest, there is a lot of heated, scientific and general discussion in gearspace on slats configurations. Regarding how much is taught in university from an acoustician point of view I would personally love to know.

Generally speaking standard slat configuration will only reflect some of the highs depending thickness and width.

1D random binary slat configurations could add some basic, weak diffusion which is better nothing or a bare wall and is often used though not necessarely preffered over the 2D random binary panels such as the bad RPG.

There are other slat configurations such as Newell seuquence incuding many others from people in the trade who tweak and adapt the sequence according to their needs.

The above standard slat configuration at least from my understanding doesn't do much other than aesthetics and keep a little of the upper frequencies. Plus, on a back wall, sitting so close to it demands absorbtion.

You have made the move I don't think it will be detrimental to the sound though there always is a better way.

I don't really see a more diffused field from the ETC graph the better decay could be from absorbtion.

Anyway, I will let the expert chime in.

What are Acoustic wood panels?

In the simplest terms, acoustic wood panels are panels made from a series of wood veneer strips mounted on top of a sound-absorbing sheet. These panels combine the acoustic benefits of the underlying sound panel (often made of PET) with the aesthetic benefit of a wood veneer top. While most commonly installed on commercial or residential walls, these panels are lightweight enough to be installed in most ceilings too.

Goto Deco Sound to know more.

As an acoustically strong, aesthetically pleasing, and easily installed interior design solution, it’s no surprise that acoustic wood slat panels are becoming increasingly popular in modern offices, modern homes, modern restaurants, and modern hotels.

Do acoustic wood panels work?

Loftwall’s acoustic wood panels have a sound-absorbing NRC grade of 0.8, which means they absorb 80% of the soundwaves they come in contact with. By contrast, standard wood panels have an NRC grade of around 0.1 – so acoustic slat wood wall panels have 8 times the sound-dampening ability of traditional wood sheets.

slat wall panel sizes and finishes

While wood acoustic panels can be constructed in various sizes and styles, the most common offering is premade 2′ wide x 8′ tall sheets of black PET backing with either Oak, Teak, or Walnut wood slats on top. Oak is the most popular finish choice. While some manufacturers offer larger sizes (like 2′ wide x 8′ tall), multiple slat wood panels can be field cut and installed next to each other to cover large areas better.

Want more information on Acoustic Slat Wood Wall Panels(tr,es,hu)? Feel free to contact us.

Free wood slat wall sample box

Manufacturers understand the importance of choosing the perfect finish for your acoustic wood slat panels. That’s why many offer the convenience of ordering sample boxes featuring a range of finishes, including oak, walnut, and teak. These sample boxes allow you to experience the textures, colors, and grains of different wood finishes firsthand, helping you make an informed decision before making a purchase. This hands-on approach ensures that your acoustic panels not only meet your acoustic needs but also seamlessly integrate with your interior design vision.

To order a free acoustic slat wood panel sample kit, click the button below.

Order Sample Box

Installing acoustic wood panels

When you’re ready to install your wood slat wall panels, here’s an install guide that covers wall mounting with screws, adhesive, and furring strips and ceiling mounting with furring strips or into t-grids. When installing wood acoustic panels, consult with a licensed contractor to ensure your office or home walls and ceilings can support the weight of slat panels.

For more Acoustic Panelsinformation, please contact us. We will provide professional answers.

Additional Resources