Assignment 6: Calculations Do the following on paper, scan or photograph your work, and submit it. You have a room that is 4 m long, 7 m wide, and has a ceiling height of 3 m. The floor is hardwood

Resonant Absorbers

Notice that to the right of the octave-band absorption coefficients, there is a column labeled "NRC." This is the noise reduction coefficient, and is simply the average of the absorption coefficients in the 250 Hz, 500 Hz, 1 kHz, and 2 kHz bands. For this product, that calculation would be:

You've probably also noticed that some of these absorption coefficients are larger than 1. This is an artifact of the standard measurement protocol, and is very common. The measurement protocol only accounts for the surface area of the face of the material, not the edges. The edges absorb some sound, though, and so the total absorption ends up being more than 1. This isn't a problem, because the edges still exist when the panels are installed in real rooms. The high absorption coefficients automatically take the edges into account when doing calculations.