First, a little quick theory on acoustics.

Remember the game of Pong on the computer where the ballet bounces all around the place? Acoustics is kinda like this.

The sound bounces off the hard walls, back and forth until eventually the sound dies down. The bigger and harder those walls, the longer and louder the reverberation is.

If you think about your walls as mirrors and you have two opposing walls, the sound is going to bounce for a very long time back and forth.

But if on ONE of those walls you put something soft that is NOT a mirror on the wall, it’s going to stop the reflection on THAT wall, but not the other one. However that’s fine. The sound will bounce off the first wall, hit the second and stop.

Why is this important?

You don’t need to put acoustic treatment on all walls, only ONE of the two reflecting surfaces.

This saves you lots of funds. You just want to stop the back and forth transmission and don’t necessarily need to cover the entire wall space.

Now a room normally has 4 walls, ceiling and floor. You can’t do much to the floor. The ceiling is often already not too bad in a factory as it’s tin and insulation. So that leaves you with typically 4 walls. But you really only need to cover 2 of them side by side (not parallel) to hit your 80/20.

So then it comes to WHAT to use to treat it.

Density and thickness tends to be the thing here. Thin and lightweight foam won’t do too much. Those pinboard panels from Bunnings aren’t going to do much for your situation, most likely.

Be careful with ones from eBay as many will not have high enough density to do much. If it feels like a sink sponge or your typical packing foam, it’s not dense enough. They are just bits of foam that someone has called ‘acoustic’.

The high density stuff actually feels almost hard.

To play it safe, I’d purchase from a more reputable place just to be sure you’re getting the real thing.

I’ve not needed to use them in my studios, but I’d recommend the ones from DJ by the looks of them. Well priced and they should be the real deal.

I’ve not compared to see if eBay is much cheaper. But you could always get one from each and see if they feel the same.

Something like this – https://djcity.com.au/product/ave-isopeak-acoustic-foam-peak-black-50-pack/

Then I’d look at covering about 30% of each of the two walls with the panels spread out evenly over the space.

An alternative is a big, massive, heavy curtain drape.