Copolyester & Engineering Bioplastic Score Highly in Molded Acoustic Enclosures

Collaboration with audio product development pro resulted in in-ear monitor housings with superior acoustic performance. 

Eastman Chemical’s proprietary amorphous copolyester Tritan and new Treva engineering bioplastic, which falls into the family of cellulosics knows as cellulose acetate propionate (CAP), both scored highly in an audio application dominated by PC.

Working with recognized acoustics product development firm DW Designs, Port Hueneme, California, Eastman Chemical molded and tested beryllium models in-ear monitor housings using a variety of materials. The findings were presented at the annual Rocky Mountain International Audio Fest (CanJam), held in Denver Oct. 5-7, by DW Designs’ principal Dan Wiggins and Eastman senior application development engineer John Quigley.

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Said Quigley, “Eastman wished to understand how our polymers might improve acoustic performance in audio applications. We worked with DW Designs to test housings molded in an incumbent PC material, as well as Eastman’s copolyester and cellulosic resins.”

The collaborators tested each of the polymers for both cumulative spectral decay (CSD) and total harmonic distortion (THD). Data show the copolyester outperformed the PC, while the cellulosic offered superior results in terms of clean response and lower distortion. More specifically, the PC had the most peaks for resonance whereas the cellulosic had the lowest overall level of measured THD.

Said Wiggins, “Eastman polymers have shown, through my independent testing and experimentation, to provide measurable and audible improvements in many products that utilize plastics. Easy to mold, durable, incredibly high internal energy dissipation, and affordability make products like Tritan and Treva a no-brainer for many consumer audio products. They are now my ‘go-to’ recommendation for molded acoustic enclosures.”

The data demonstrated that Tritan copolyester and Treva cellulosic both have superior damping characteristics relative to PC. Moreover, expert listener feedback demonstrated that consumers were able to hear fine details better and preferred the acoustic performance of the Tritan and Treva.