Manufacturer
Question: Samuel D. (Willoughby, OH) Hello. I need your opinion on the attached data. BASWAphon stocks the 30 mm system and the 70 mm system (formerly the 68 mm system) and also currently stocks the 40 mm system. The pre-coated panel is now “pre-sanded” which greatly opens the pores and increases the sound absorption. Preliminary sound absorption coefficient lab test data are attached If we intend to stock either the 40 mm system or the 50 mm system (in addition to the 30 mm and 70 mm systems), do you have an opinion which system best compliments the thin and thick systems? Thanks.
Sound-Answers.com
We reviewed all the test data and graphed all four sets of sound
absorption coefficients (see attached chart and spreadsheet).
Absorption coefficients increase as material thickness increases ~ but
only in certain frequency ranges. So for example, the 40 mm and 50 mm
systems behave pretty much the same acoustically at 400 Hz and above (as
one would expect). The average absorption coefficient for the 40 mm
system from 400 Hz and above is 0.91. The average absorption
coefficient for the 50 mm system from 400 Hz and above is 0.90. These
values are pretty much identical, so there is no real acoustical
preference for one system over the other above 400 Hz.
As shown in the graph, the only significant difference between the 40 mm and 50 mm systems occurs in only a narrow band of lower frequencies between 160 Hz and 315 Hz (as one would expect). The average absorption coefficient for the 40 mm system in this range is 0.50, while the corresponding average absorption coefficient for the 50 mm system (in the same frequency range) is 0.65 ~ an improvement of 15%.
So in summary, it is safe to say that based on the test data at hand the 40 mm and 50 mm systems behave very similarly to each other, but the 50 mm system is about 15% more absorptive in the 250 Hz octave band. If all else were equal (meaning installed price, etc.) we would suggest that you stock the 50 mm system and discontinue the 40 mm system. Also, 50 mm is very close to 2 inches, which might just be easier for architects and contractors to detail, especially when the BASWAphon abuts another material.
