Cardboard boxes for room echo reduction?

Question

I have a large amount of not-broken-down cardboard boxes that I need to hang onto, and they are piled just outside the door of the small basement room I am trying to use as a (admittedly incredibly primitive for now) recording room. That room seems to have some echo that is probably not good for my recordings and I'd like to reduce it or eliminate it for free or very close to it.

I wanted to try moving the boxes into the studio to see if that would do the trick. What I've seen online is that (broken down) cardboard affixed to walls can help with echo, but I do not want to break these boxes down, as I need them eventually for moving. (Yes, I can always get more boxes for free but it's a hassle and not always the cleanest thing and these are exactly right for moving, so I'd rather just keep them).

Any thoughts on whether this should work? I could do the experiment but I'd rather not attempt it if it's going to be futile.

Answer 1

They will be able to reduce echo in their complete state, but don't expect them to help too much, as there are some caveats:

• Just piling them up in a corner won't be very effective - they will absorb many frequencies better than a solid wall, but you still have flat reflective surfaces, and they will each have a resonant frequency. As long as the resonant frequencies do not support the frequencies you wish to attenuate, this will help a little.

• Trying to pile them at a range of different angles will help a little more, but they will still be reflecting sound, so you may get some interesting echoes.

• If you can fold them down even a little to remove right angled corners you will help yourself a lot. Especially if you can attach them to walls with the flaps hanging - these will damp sounds more than rigid panels.

tl;dr they will help a bit, but don't expect dramatic sound improvement :-)

Answer 2

To understand how to best treat a room acoustically, it usually helps to understand why the problems exist.

In the case of echo, this is usually smooth walls that are perpendicular to each other. Since you can't exactly move your walls, a better option is to hang something like a sheet or curtains across your walls. Setting it about an inch off your wall will have the most impact, since you're trying to provide absorption at a distance equal to 1/4 of the wavelength of the frequencies you want to absorb.

If you only have the boxes to work with and can't break them down, then instead of stacking them up, you would do better stacking them sideways at angles and opening them up. The more you can prevent smooth surfaces, the better. Stuffing them full of t-shirts, blankets, sheets, etc. helps even more.