Short answer: Yes, moderately. ACRYLITE rates its extruded sheet at sound transmission class (STC) 23 at 1/8 in. (3 mm), 26 at 3/16 in. (4.5 mm), 28 at 1/4 in. (6 mm), and 30 at 3/8 in. (9.5 mm), and Plaskolite lists 27 dB for OPTIX sheet. Like any barrier, acrylic blocks sound mainly by weight, so thicker is quieter. It only works if the installation is airtight: ACRYLITE notes that good sheet won't help a window that leaks air, and a sealed second layer with an air gap does far more than a thicker single sheet.
Key facts
| ACRYLITE extruded sheet | Average sound transmission loss, 100 to 3,200 Hz | STC |
|---|---|---|
| 3 mm (1/8 in.) | 22 dB | 23 |
| 4.5 mm (3/16 in.) | 25 dB | 26 |
| 6 mm (1/4 in.) | 28 dB | 28 |
| 9.5 mm (3/8 in.) | 30 dB | 30 |
- Plaskolite lists sound transmission of 27 dB (ASTM E90/E413) for OPTIX extruded sheet.
- ACRYLITE's values assume airtight, resilient mounting.
- Bigger panels pass more sound: ACRYLITE says doubling the area increases transmission by several decibels.
What does STC mean in practice?
Sound transmission class is a single-number rating of how much a barrier reduces airborne sound across speech frequencies. Higher is better, and a change of a few points is noticeable. Single panes of acrylic land in the mid 20s to about 30, in the same general range as single-pane windows. Acrylic is not a soundproofing material on its own, but it can take the edge off traffic, voices, and machinery, especially as a second layer.
Sound blocking by a single panel is mostly about mass. Acrylic weighs about half as much as glass for the same thickness, so a pane of acrylic needs to be somewhat thicker than glass to match it. Going from 1/8 in. to 1/4 in. acrylic gains about 5 STC points in ACRYLITE's data; going to 3/8 in. gains about 2 more.
Why is low-frequency noise so hard to stop?
Low rumble from trucks, engines, and bass has long wavelengths that flex a light panel and pass through it. Higher-pitched sounds such as voices and whining machinery are much easier to block. That's why an acrylic insert makes a street quieter but doesn't erase a passing bus. More mass, a wider air gap, and two panes of different thickness (so they don't resonate together) all help with the low end.
What makes an acrylic sound barrier work?
- Airtight edges. ACRYLITE lists weight, area, rigidity, and air tightness as what decides sound reduction, and stresses that acrylic with good sound reduction may not improve a window that isn't airtight. Seal the perimeter with a gasket, foam tape, or flexible sealant.
- Mass. Use the thickest sheet the frame and budget allow; 1/4 in. is a common choice for window inserts.
- An air gap. A second pane with an air space works better than one thick pane, because sound has to cross two barriers and the air between. This is how interior storm panels work; PNNL's Building America guide notes that both plastic and glass interior storm panels improve sound control by cutting air leakage.
- Smaller, stiffer panels. Large panels flex more and pass more sound. Add mullions or supports on big openings.
Common uses
- Interior window inserts for street noise: 1/4 in. acrylic in a sealed frame inside the existing window. They also cut heat loss; see does acrylic insulate.
- Machine and booth enclosures, where you need to see in. For impact-prone guards, polycarbonate may be the better choice; see acrylic vs polycarbonate.
- Desk and office dividers, which reduce direct speech but can't block sound that travels around them.
- Recording and podcast booth windows, usually two panes of different thickness with a sealed gap.
We cut inserts and panels to size with clean edges and drilled holes; measure first with how to measure for acrylic cut to size and price it in the instant quote.
Questions
Is acrylic or glass better for soundproofing?
For the same thickness, glass is heavier and usually blocks a little more sound. Acrylic's advantages are safety in large panes and being easy to cut, drill, and fit as a sealed, removable insert, which often matters more than the material.
Will acrylic panels reduce echo in a room?
No. Acrylic is hard and reflects sound, so it can add echo. Use soft absorbing panels for echo, and acrylic to block sound passing from one space to another.
What thickness acrylic is best for a soundproof window insert?
1/4 in. is a common balance of weight, cost, and noise reduction (STC 28 per ACRYLITE); 3/8 in. reaches STC 30. A fully sealed perimeter and an air gap from the existing glass matter as much as thickness.