What Difference Do Voids Behind Panels Make?

July 7, 2025

When you’re putting together a workspace, acoustics can easily slip down the priority list. But it’s one of those things people really notice—whether a room feels calm and comfortable or noisy and distracting often comes down to how sound behaves.

And there are always ways to upgrade your acoustic products to get the best performance out of them. Such as creating a bit of space—a void—behind the panel can seriously boost how much sound it soaks up.

For example, we tested our Ora Plain panels in different setups. A 12mm panel stuck straight onto the wall has a certain level of sound absorption (an NRC of 0.40). But add just 25mm of empty space behind it, and the rating jumps to 0.60. Not bad for a small change! Then, if you pop in 50mm of acoustic wadding behind it, that number shoots up to 0.95, which is Class A, top-notch performance.

It’s the same story with the thicker 24mm panels. Put them flat on the wall, and you get an NRC of 0.65. Add a 100mm void behind, and you’re up to 0.90 (Class A). Add even more acoustic wadding, and you’re at 1.0 NRC.

Why does this work so well? Think of the void like a little trap for sound waves. When the panel is flush on the wall, it can only absorb so much. But with some space behind it, those sound waves get caught, lose energy, and don’t bounce back into the room as much. And if you fill that space with acoustic wadding, it’s like giving the sound even more places to disappear.

So, when you’re planning a space where good acoustics really matter—like a meeting room or open office—don’t just think about the panels themselves. Think about how they’re installed. Sometimes, a small gap behind the panel can make a big difference without needing a different product.

Want to explore acoustic solutions that are tailored to your next design project? Take a look at our full range of acoustic solutions here or give us a call on +44 (0)20 3889 9888, email us at hello@allsfar.com or fill in our contact form on our website here.

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