A lot of my musician friends are discovering just how viable it is to produce their own material in the spaces available to them regularly. Under the right circumstances, doing so allows for leaner budgeting, and even a much steadier release cycle. (You can work with and release tunes on, say, a monthly basis, rather than wadding everything up into a do-or-die album process that takes years.)
In the DIY-recording realm, a point of confusion tends to be the difference between acoustical treatment and soundproofing. I’ve heard more than one person refer to the placement of acoustical foam on various surfaces as “soundproofing,” and while I understand what’s actually meant, the terminology is still off.
So, what’s the difference?
It’s actually a fairly simple distinction, at least as I’ve come to understand it. Acoustical treatment is modifying the behavior of sound within a space. Soundproofing is preventing the transfer of acoustical events between spaces.
To be fair, acoustical treatment can – technically – aid in some soundproofing. Acoustical absorption means that sound energy is converted to thermal energy. If, through something like acoustical foam, a sonic event is prevented from ever reaching a wall, then you won’t have a problem with that sound causing the wall to vibrate. At the same time, it’s important to note that most building structures are less and less likely to vibrate effectively at higher and higher frequencies anyway, with the losses from acoustic foam quickly becoming essentially irrelevant.
Soundproofing is a much more difficult business, because it requires getting a handle on vibrations that are very strong and difficult to stop. It’s a game of mass and isolation. Very heavy objects are difficult to set into motion. Objects that have less surface-area in contact with other objects transfer vibration poorly. The transfer of vibration from air to solids is highly inefficient; You can easily feel a big thump on your chest from someone’s hand smacking into you, but that same sensation from a subwoofer firing into the air requires a TON of speaker power.
So, with all that, effective soundproofing tends to rely heavily on expensive, permanent (or quasi-permanent) construction. Rooms can be built within other rooms, for instance, with air gaps between the outer and inner walls. “Airlock” systems with multiple, heavy, gasketed doors can be employed. Floors may be floated with absorptive rubber spacers.
A room can be nicely soundproof, but sound terrible inside. Build a concrete bunker inside another concrete bunker, and not much sound will get in or out. The reflectivity of all those hard surfaces will be horrendously bad, though.
Basic treatment, on the other hand, is much easier. Gather up a few thick, fluffy blankets that you can hang, and you’re likely to create a noticeable change in the room’s internal behavior. Reducing the “splatter” of content at or above 1000 Hz isn’t exactly trivial, but the effort required is within reach for almost anybody.
(Please be aware, of course, that really great sounding rooms almost never happen by accident or by way of a few, hasty changes. Full-blown, world-class acoustical spaces require a great deal of thought and preparation. The best ones have effective treatment at low frequencies, which is not a simple thing to do. Big studios with renowned rooms are expensive for reasons that include both soundproofing AND treatment.)
As I said, room treatment and soundproofing aren’t the same thing. In your self-recording adventures you’ll likely encounter some “environmental” problems. Figuring out which of the two concepts applies the most will help you approach the issue in a way that actually has a chance of being effective.