best soundproofing material

I am a serious movie buff.  And like all movie lovers, I know that the best way to watch movies is to kick back in my own home theater.

In this post, I share what I learned while looking for the best soundproofing materials for my home theater.These materials are good for soundproofing any room in the house.

So, if you want to soundproof a baby’s room or a bedroom, these are the ones you need to be looking at.

Best Soundproofing Materials

Identifying stuff that will work well is essential for a successful soundproofing project. I see many products which are marketed as soundproofing materials. I have written articles on the uselessness of egg cartons and acoustical foam. Do check them out.

The best soundproofing materials are as follows:-

1. Soundproof Drywall
2. Fiberglass Insulation
3. Green Glue Damping Compound
4. Soundproofing clips for decoupling
5. Solid Core (material) Doors
6. Soundproof Door Seals
7. Soundproofing Sealant
8. Soundproofing Putty Pads
9. Soundproof Underlay For Floors
10. Joist Isolators and Cable Isolators

Soundproof Drywall

The walls of my HT needed to be soundproof, not just for my benefit but for my neighbor’s as well. Soundproofing requires extra mass, so drywall would have to be added.

The question was whether to opt for soundproof drywall or not. A ‘soundproof drywall’ is typically made of a damping compound sandwiched between two layers of drywall.

A good brand like QuietRock charges around 60-70 USD per sheet of soundproof drywall. Compare this to two sheets of normal sheetrock which has double the mass. Moreover, two sheets of sheetrock cost lesser than one sheet of Quietrock.

So I chose to opt for three layers of 5/8^” of drywall instead. I also used good fiberglass insulation and a damping compound. If you are looking for cost effectiveness, it doesn’t get better than this.

There are some advantages to using ready to install soundproof drywall. It can help save precious inches off space used in soundproofing. If space is a bigger concern than money, Quietrock could be an option. Keep in mind that an extra layer of drywall will take up only an inch of extra space.

Fiberglass Insulation

All the walls in my HT room were to be decoupled. But even decoupled walls with staggered studs can continue to transmit sound.

This is because the cavity in between barriers is not exactly a strong point of a soundproof system. By adding a suitable insulation like fiberglass, this problem can be solved.

Fiberglass has a very useful structural property. It has many air pockets where sound can be trapped. Introducing high-density fiberglass helps in increasing the STC value of barriers.

Insulation will only help if you have managed to remove other problems like mechanical connections because of studs.  In case the studs are in contact, no amount of insulation will help because sound has a path to travel across.

It has also been found that beyond a particular density, fiberglass insulation reduces performance at lower frequencies by increasing resonance. Higher density fiberglass is also costlier. So, it is better to opt for the normal loose fiberglass.

You should also stop yourself from stuffing the cavities with insulation. It doesn’t help to pack insulation beyond 50% capacity. From nothing to 50% insulation, the difference in STC value is noticeable. But beyond 50%, you cannot notice any improvement.

Read my article on best insulation for soundproofing and acoustics.

Green Glue Damping Compound

I wanted to soundproof the apartment but also wanted to save space and money (who doesn’t). A good damping compound like Green Glue is a savior.

You can use Green Glue on pretty much any surface ranging from drywall to fiberboard. A damping compound works by converting the energy of the sound which comes in contact with it into heat energy. This then dissipates and cannot travel through the barrier.

These compounds help make soundproofing much more efficient. With thinner layers of drywall, we can achieve higher STC values by using damping compounds. The best part is that you can use these compounds without any professional help since they are so foolproof and accessible.

The only downside probably is that damping compounds take some time to mature. So if you don’t have a couple of months to let the effects kick in, you might have to look for other products. As for the price factor, it is incredibly affordable. You can buy quality damping compounds like Green Glue for around 0.50 USD per square feet.

More about Green Glue in this article here.

Soundproofing Clips for Decoupling

 

Decoupling is a great way to increase the STC value of walls. But I didn’t want to sacrifice a lot of space in trying to marginally improve soundproofing.

Staggered studs help in saving some space. But it is possible to get better results by using decoupling hardware.

A typical interior wall which has a single layer of ½” drywall on each side with wood studs and no insulation has an STC value of 33. This is what is mostly found in homes which were built before the new building codes came into practice (requiring a minimum STC value of 50 for multi-family buildings).

Even if you do live in a house which has poor STC values, you can improve the acoustic isolation by using intelligent products like sound isolation clips for decoupling.

These clips are attached to a layer of drywall and the second layer of drywall is screwed onto a hat channel fitted on the clips. In this manner, the wood studs cannot transfer sound from one side to the other.

Lots of progress has been made in this category over the past years and you can choose a suitable product matching your budget and needs. You can source 10 clips for as little as 5.25 USD.

Resilient channels are another option. They cost less but their chances of success are also quite low because of the difficulties involved in installation.

All in all, these products can help you add significant STC points to soundproofing assemblies depending upon other factors like thickness of the drywall, the gap between two layers, and insulation.

Solid Core (Material) Doors

For a door to not be a weak link in the area, it needs to match the STC value of the surrounding walls. If we try to increase the STC value by increasing the mass of the door, we end up with a mammoth door which is extremely expensive and not functional.

Readymade Soundproof doors are quite effective but are very costly. The best type of door is a Solid Core type which is very dense and heavy. A communicating door assembly with solid core doors is the most cost-effective solution. This will still cost you about $500 but much lesser than readymade soundproof doors costing over $4000.

For a more detailed explanation, read Best Ways To Soundproof A Door.

Soundproof Door Seals

No matter how perfect our soundproofing project is, the tiniest of gaps around the doors can wreck the whole enterprise. Even if the door has an excellent STC value, without good seals, sound will be transmitted across it.

Door bottoms and jambs require special attention. Door jambs provide a flanking path and can be a real pain. Good soundproof door seals are something you might want to invest in.

If you opt for communicating doors, the space between them reduces the flanking effect of jambs. This might be a more affordable and accessible solution. Of course, space is a factor over here as we discussed earlier.

Soundproofing Sealant

I cannot possibly stress enough on the necessity of using a good acoustic sealant. After spending a good amount of time and money, skipping on this crucial step might come back to bite you. It is almost like making a perfect meal but not adding salt.

Invest in a good acoustic sealant and get cracking on all the joints, the electrical fixtures, and the pipes. Unless you seal them well and good, the tiny gaps will increase sound transmission and ruin your entire system.

While buying your sealant, you might want to buy the cheapest off-the counter caulk. I’m not going to lie to you, I thought about it too.

The problem is that caulk tends to harden and develop cracks over time. And then we are back to square one. It is better to opt for a slightly better professional grade sealant which is long-lasting and costs only fractionally more.

Soundproofing Putty Pads

Electrical boxes are a necessary evil in a soundproof room. The best of us have been let down by the presence of back to back electrical boxes.

Even when not close together electrical boxes which are not properly insulated will mess with your soundproofing.

A nice way to tackle this is to get some acoustical putty pads and get sealing around the boxes. This is a watertight arrangement and will not disappoint you. The putty is flexible and will not crack over time.

If you are looking to save some money off the insulation budget, you could try using butyl adhesive flashing tape from your local hardware store.

I must warn you though, if you walk down this road, you will have to spend more time on the job as you will need to cut the tape into tiny pieces in order to wrap near wires.

So it is up to you really whether to save time or a little money. But do not leave the electrical boxes unguarded.

Soundproof Underlay

If you didn’t think it important to soundproof the floor, you’re not alone. People think that soundproofing walls is more important and have a habit of thinking the least about the floor when it comes to soundproofing.

But you don’t want the floor to be a massive path for sound transmission, isn’t it? So you will have to do more than laying down a thick carpet and hoping for the best.

When the floor is being constructed, you can add layers of OSB coated with a Green Glue and a layer of rubber mat which would be fairly economical.

But if your building is complete, acoustic underlay mats are a great help. They can help reduce both airborne sounds as well as footfall impact noise. Acoustic underlayment also helps floors resist mold formation, which is an added advantage.

Here is my top recommendation for underlayment.

Joist Isolators and Cable Isolators

Impact noise quickly spreads from a floor surface to the joists and from there it passes on to the ceiling.

To stop this from happening, you can use joist isolators when building a floating floor. It is a neat little way of enhancing your soundproofing efforts.

Joist isolators are quite affordable and can be used with standard lumber for a decoupled framing for your floor.

When building a soundproof ceiling, it is equally important to decouple the drywall from the framing. Then there are the ventilation ducts and pipework which are prone to vibration.

Cable isolators come to the rescue here. The vibrations from the ductwork and other suspended building systems are simply stopped midway by these. They no longer transfer onto the floor or ceiling structures and can’t damage your soundproofing project.

Final Thoughts

So, these were some of the high performing soundproofing products. This list is in no way exhaustive. Soundproofing is a technical exercise and you have to test the waters before you dive right in.

I have tried to list the best starter materials and the ones you will likely use during your project. They provide a bang for your buck. Go on then, take your pick and pump up the volume!