You’ll get better results if you soundproof the whole wall. A hole through which light can pass can also let sound waves in. Acoustical or silicone sealant applied to holes and cracks can block enough sound to make a difference. However, the more layers absorb vibrations and slow or stop sound waves, the less noise you’ll have. 

Both plaster and drywall are durable wall finishes, but they differ significantly in installation, cost, performance, and aesthetics.

Installation & Cost: Drywall installation is faster and more affordable, typically costing $1.50 to $3 per square foot. It uses premade sheets, making it a more accessible DIY project. Plastering is a labor-intensive craft that requires specialized skills, pushing costs to $2 to $10 per square foot. It involves applying a wet paste over a lath framework.

Durability & Performance: Plaster is generally more durable, longer-lasting, and provides superior soundproofing. It is also a better insulator, which can help reduce energy costs. Drywall is easier to remove for future renovations.

Aesthetics: Drywall provides a smooth, uniform surface ready for paint or texture. Plaster offers a high-end, naturally textured look that can hide imperfections and is often preferred for achieving a classic or historic aesthetic.

Which is better? The choice depends on your priorities. Drywall is ideal for those prioritizing a lower upfront cost, faster installation, and DIY potential. Plaster is the better option for a higher-end project where durability, soundproofing, and a unique, premium finish are more important than the initial cost.

If your home was built before the 1940s and was not remodeled in the past 50 or so years, you probably have plaster walls. Aside from assuming, there are some practical ways to tell if you have plaster walls, including the following: If you knock on the wall and it feels solid, not hollow, if you can’t insert a thumbtack easily, if there are cracks that look like spiderwebs, or if your home has curved, arched, or swirled walls, doorways, or window openings.

If you have an unfinished basement or attic, you could examine the backs of any finished walls to check, too.

A jigsaw is commonly used to cut holes in drywall. It offers versatility and precision, making it suitable for creating circular or irregular openings. When equipped with the right blade, a jigsaw can swiftly and cleanly cut through drywall, making it a good choice for DIY projects.