This paper discusses the results of an experimental study on sound absorption of a number of automotive carpet materials. The results are compared to each other and to other “acoustical materials”.Initial impedance tube measurements of 18 different materials showed the expected trend of increasing absorption as thickness increased. Twelve materials were then tested in a reverberation room. Test results showed that most materials had significant absorption above 500 Hz with values for the better materials approaching values for fiber glass. Absorption correlated highly (r = 0.92) with thickness and very highly (r = 0.98) with the product of thickness and surface weight, indicating that the absorption of new constructions can be predicted. However, reverberation room results did not correlate well with impedance tube results.