In more than one occasion we've seen giant flame wars focused on certain audio equipment, speakers, cables, and compression formats, but most of their participants tend to forget two things: that our ears worsen with age, and that the environment can greatly modify the final quality. Anyone needing solid proof will find it in the video below, which shows the difference between popping a balloon in a reverberation room and repeating the same process inside an anechoic chamber.
A common shortcut to preserve audio quality while also bypassing any physical limitation is using headphones. That's what I've been doing in recent years: my “personal cave” has so little space that I almost have to enter it like a Tetris piece (?), and the idea of installing speakers with decent specs is discarded from the start. Why? The answer forces us (in part) to explore the phenomenon of reverberation.
What Is Reverberation?
Its basic definition describes it as a persistence of sound after the source has interrupted its emission, caused by reflection. Echo is nothing more than a clear interpretation of that reflection, but if its effect is a modification of the original sound through multiple reflections on different surfaces, we must speak of reverberation.
American physicist Wallace Clement Sabine, considered the father of modern architectural acoustics, concluded that reverberation time (the time it takes for reflections of a direct sound to decay by 60 decibels) is proportional to the dimensions of a room, and inversely proportional to the amount of absorption. A good demonstration is in the first video I just shared.
The first part shows that the balloon pops and its sound remains for several seconds after the explosion, but exactly the opposite happens in the second test. Anechoic chambers are essentially anti-reverberation, absorbing a very high percentage of reflection (above 95 percent). If you want something a bit more elaborate than a balloon, here's a saxophone:
How do they achieve that? With the help of surfaces unfriendly to sound reflection, which also seek to scatter when absorption is not possible. Another very interesting aspect of anechoic chambers is that they are not limited by size. Some are as large as a refrigerator, while others occupy entire hangars.
