Do you remember when you were a kid that the closest thing you had to a cell phone at the time was two cups with a string tautly attached between them, and then speaking into one cup to see if your friend holding the other could hear you? That long-ago game worked because sound travels along rigid pathways. If you let the string between the cups go slack, the sound doesn’t travel. That’s all you really need to know to understand soundproofing – and you had already learned it in kindergarten.
The ABC’s of Sound – and Soundproofing
Sarah Marsh, President of MAAI Marsh Architects in New York City, says: “There’s no such thing as soundproofing; rather the proper term is sound attenuation.” Sound attenuation is the effective reduction of sound – not necessarily its elimination.
Michele Boddewyn and Alan Gaynor, President and Founding Principal respectively of the New York City firm Boddewyn Gaynor Architects, explain that noise in multifamily buildings can be broadly divided between two general categories: airborne noise and structural noise. Airborne noise filters in from adjacent units and outside. It includes things such as music from a stereo, raised voices, or the rumble of the garbage truck at 6:30 on a Saturday morning. Structural noise has to do with reverberations that come through the actual building structure – so the reviled ‘footfalls’ of your upstairs neighbor’s children and her high-heeled shoes clacking against the floor at the same time every day count as structural noise.
Solutions for these different types of noise vary in approach. In reality, the underlying science behind the solutions is pretty much always the same: relax the string.
An Unintentional History
Urban multifamily housing can be pretty much divided into three categories as far as sound is concerned. The first period stretches from World War I through the pre-World War II construction boom, and then on to the mid-1960s, when construction methods began to change for both economical and technological reasons. The second period covers the years from the late 1960s and early 1970s through the early 1990s. The third period begins in the 1990s and brings us to the present.