marpiler1 wrote:Hi everybody. New here so apologies if I seem a little clueless.
Welcome to the forums. There's no knowledge threshold to ask questions here, and none of us was born knowing all the answers...
I've deleted your second post, partly because it didn't ask anything more than you already asked in this first one, and secondly because of the included link which, from a newbie with no posting track record, could be considered spam (and we have had issues in the past with that particular company...)
Nevertheless, the topic will be of interest to others so here's my take on it:
I've been looking around and have noticed that there are many different shapes and styles of acoustic foam. My question is, does it make a difference? Or is it just an aesthetic thing?
It's mainly an aesthetic thing.
Foam works as an acoustic absorber by forcing the air particles moved by sound pressure waves to enter the labyrinthine cells of the foam, losing energy as they go through friction. In that way, sound enters the foam and is absorbed, preventing reflections back into the room. With reduced reverberation and reflections, the sound heard by you or your microphones is mostly the direct sound from the speakers or instruments, generally resulting in better perceived quality.
However, it is the overall thickness of the foam that determines the frequency range over which it is effective, with the maximum absorption occurring at frequencies above the point where the thickness is 1/4 of the sound's wavelength. The reason for this rather odd fact is that at the boundary (ie. wall), there is maximum pressure but zero particle movement -- so the part of the absorber next to the wall does nothing at all! -- whereas the greatest movement of air particles occurs a quarter-wavelength from the boundary, where the pressure is zero.
For this reason, it is usually recommended to space the foam absorber panel away from the wall, typically with a gap behind it roughly equal to the thickness of the absorber itself, as this will maximise it's efficiency and working bandwidth. So a 2-inch thick panel should ideally be fixed 2-inches out from the wall.
The issue with pyramid foams and the like is that although they look pretty, the average thickness is greatly reduced, potentially making them less effective at lower frequencies... but against that is their increased surface area which may help to soak up oblique sound waves...
At the end of the day, I'd advise picking a foam style that you like the look of because you're going to be staring at it for a long time.... but buy the thickest panels you can and mount them away from the wall, not directly on it.
Better still, build your own broadband acoustic absorbers using mineral wool which will be cheaper and more effective. There are lots of designs on the web as well as in the Studio SOS articles from the magazine (which are all available free on this website.)