ᐅ Is it worthwhile to add sound insulation to the open Kallax shelving unit?

Hello everyone, I am considering adding acoustic insulation to my open Kallax shelf to reduce the sound that escapes through the cavities and the back panel to the rear and sides.

My specific question is: Is it really worthwhile to apply acoustic treatment to an open shelf like the Kallax, given that it is not fully enclosed?

I am not referring to traditional insulation, but rather measures such as using sound-absorbing materials inside the compartments or on the back panel to reduce the room’s reverberation time. Has anyone had experience with this and can say whether it actually makes a noticeable difference or if it is more likely a waste of time and money?

Thanks for your evaluations!

Rukin schrieb:
Is acoustic insulation really worth it for the open Kallax shelf

Hello Rukin,

I find your approach very interesting! In general, open shelves typically don’t act as traditional sound barriers due to their design. Sound absorption is often quite low since air can freely circulate through the openings.

If you line the compartments with sound-absorbing materials like acoustic foam or mineral wool, you can reduce reflections inside the compartments. However, this only helps significantly if most of the sound is reflected within those chambers. With fully open shelves, sound usually spreads freely throughout the room and isn’t only influenced by the shelf itself.

Another point: The insulation materials used need to be well matched to the frequency range you want to reduce. Bass issues are difficult to control this way; it’s more effective for mid to high frequencies. Since the Kallax uses relatively thin panels, insulation may help somewhat with impact noise or vibrations if the shelf is placed against a wall.

In summary: Yes, it can help, but only to a limited extent and mainly in specific spots where reflections are a problem. Simply adding material and expecting a miracle is not realistic. If you want to know more precisely what effect you can achieve, it would be advisable to start with a small test setup.

I hope this helps you!

Keatondra schrieb:
Sound absorption is often rather low there

I agree with that and would like to add that besides pure acoustics, the shelf’s usage also matters. For example, if you often listen to or watch music, light insulation can actually be more pleasant because absorbing unwanted reflections improves sound quality.

Rukin schrieb:
Does anyone have experience whether this actually makes a noticeable difference?

Some time ago, I fitted my Kallax with felt panels in a few compartments—not mainly for sound absorption, but to make the shelf feel overall more muted—especially when I had speakers placed right next to it. It wasn’t revolutionary, but yes, a slight improvement in room acoustics was noticeable, with higher frequencies becoming clearer. I can’t say if this applies to every room and all volume levels.

At least it didn’t have any drawbacks for me; it adds a pleasant “softness” to the sound. Maybe something to consider if you want to make your environment a bit quieter.

JONKO schrieb:
a slight improvement in room acoustics was noticeable

I would like to disagree and raise a few critical points regarding the acoustics:

What exactly do you mean by “slight improvement”? Are there any measurements or at least subjective evaluations? Often, we tend to “feel” improvements that are actually minimal or not present at all.

The open Kallax shelf is more a decorative piece of furniture than a soundproofing solution. It provides little structural mass compared to closed or thicker furniture. Any “acoustic insulation” you place inside would have to be very specific, and in practice I would rely more on room acoustic absorbers rather than the furniture itself.

Rukin schrieb:
Is acoustic insulation for the open Kallax shelf really worth it?

In terms of cost-effectiveness, I would rather say no. At best, you can reduce reflections with sound-absorbing materials inside the compartments, but this effect tends to be very localized. Sound passing through the shelf to the rear still escapes fairly freely. Furthermore, the impact on bass frequencies is minimal.

My recommendation: More costly insulation measures such as thicker curtains or wall absorbers provide real added value.

faso31 schrieb:
In terms of price-performance, I would rather disagree.

I would like to add a structured approach here, which is very helpful when dealing with acoustics:

1. Analysis: First, you should precisely measure or at least subjectively identify which frequency ranges bother you (bass, midrange, treble?) and where the sound is coming from.

2. Absorption locations: Open shelves are usually not a primary place for absorption, unless used as diffusers. Effective soundproofing requires materials with sufficient thickness and density.

3. Material: You can equip the interior of the Kallax with thin acoustic foam panels or specially made absorbers, but their effect will only be noticeable at high frequencies.

4. Alternative solutions: If your goal is to improve room acoustics, it’s better to place absorbers at first reflection points, use carpets, curtains, or wall absorbers.

5. DIY tip: If you still want to soundproof the Kallax, place foam on the back panel, cover interior surfaces with fabrics, or build closed spacers to reduce certain frequencies.

Conclusion: Acoustic insulation for the Kallax can be part of a solution but does not replace proper room acoustic measures. It is therefore a supplementary step if you have already optimized the room acoustics. Expectations should remain realistic. :-)