We offered 1/4" and 3/8" thick acrylic inserts for sound abatement from 2008 to 2011. But we decided to discontinue it as a primary product because it disappointed too many of our customers who had mid-to-low frequency noise/sound problems, i.e. big trucks, big motorcycles, big dogs, train rumble, a/c units, etc. It just didn't stop enough airborne noise. Our laminated glass inserts worked much better. We only use 1/4" acrylic in special cases, i.e. when the soundproof insert is required to bend.
When we started producing soundproofing window inserts, we looked for four basic characteristics in choosing materials: Clarity, Mass, Manufacturing Suitability and Cost. That leaves us with two basic choices of material: plastic and glass.
Of the plastics, acrylic was:
Of the types of glass available, laminated glass was:
Hence, acrylic was chosen as the low-cost option, and laminated glass was the expensive option.
As mentioned above, the biggest problem with using acrylic for airborne soundproofing is its mass (density). The more mass a material has, the more sound waves it can absorb. This is particularly important in our industry because mid-to-low frequency, airborne sound is often the most annoying for our customers. For example, many people are not bothered by the sound of cars on the highway. But, the loud and low-frequency sound of big trucks and big motorcycles wakes them up. 1/4" acrylic is roughly 1.45 pounds per square foot, 3/8" is 2.14 lbs/ft2. 1/4" laminated glass is roughly 3.27 lbs/ft2 - twice the mass of 1/4" acrylic. Laminated glass simply stops more sound than acrylic because it has more mass.
By 2011 our volume of laminated glass purchases had driven our costs down significantly. Plus, we'd solved the difficulties of working with laminated glass. As a result, prices came down. Many more customers could afford the benefits of laminated glass. The price difference between laminated glass and acrylic was getting smaller each year, and our customer satisfaction with laminated glass inserts was high. The scales had tipped. It was time to discontinue the acrylic option. The thinking was that increased customer satisfaction would eventually increase our buying power, driving our costs down. It worked. We now offer soundproof window inserts made of laminated glass for less than our biggest national competitor, whose product is acrylic.