You never realize how noisy the world actually is, until you first starting learning how to soundproof a room.
All that background noise you never really noticed before…
Sounds painfully obvious when heard through a condenser microphone.
So in today’s post, we’re going to learn how to solve this problem by showing you the best practices for soundproofing your studio.
So here we go…
Table of Contents:
- What Soundproofing does NOT do
- What Soundproofing DOES do
- How to Soundproof a Room: The 4 Key Methods
- How to Soundproof a Room from Computer Noise
- How to Soundproof a Room from A/C Noise
- The 4 Types of A/C’s
- One Final Thought on Noise Reduction Plugins
What Soundproofing does NOT do
When learning how to soundproof a room, newbies often confuse the terms soundproofing and acoustic treatment. So just to clarify:
- Soundproofing makes your room QUIETER, by blocking-out external noise, while…
- Acoustic Treatment makes your room sound BETTER, by absorbing excessive ambience.
Ideally, you should use a combination of BOTH. But for now, if acoustic treatment is what you want…check out this article instead:
Otherwise, let’s continue…
What Soundproofing DOES do
When a room is perfectly soundproofed:
- outside noises stay outside, and don’t disturb your recordings.
- inside noises stay inside, and don’t disturb your neighbors.
Common noise sources include:
- Outside noises: people, traffic, weather, and plumbing.
- Equipment noises: computer fans, hardware racks, and air conditioners.
- Impact noises: footsteps, and anything else making contact with the floor.
All of these have the potential to ruin your recordings.
So let’s start off by tackling those outside noises, using…
How to Soundproof a Room: The 4 Key Methods
Soundproofing is done using a mix of 4 tactics:
- Adding Mass
- Filling Air Gaps
Here’s how it all works:
1. Adding Mass/Density
To prevent sound from entering and exiting a room…
The walls of the room require lots of mass…to prevent them from vibrating in response to sound energy.
When building a room from scratch, adequate mass can be added to the wall simply by building it thick, with a dense material such as concrete.
To add mass to an existing room, you can use mass loaded vinyl, aka Sheetblock – (Amazon), which is a standard solution for both professional and DIY projects.
To measure how effective materials are at soundproofing, a metric known as Sound Transmission Class (STC) is used. Hard materials like concrete will have higher STC’s, while softer materials such as insulation will have lower ones.
Here’s a general guideline of what the numbers mean:
- 20-30 is poor
- 30-40 is average
- 40-50 is good
The other metric used is Sound Transmission Loss (STL), which some say is more accurate because it measures isolation at specific frequency bands, while STC uses just one number for the entire frequency spectrum.
Similar to adding mass, damping is a method of soundproofing that dissipates kinetic energy from sound waves by converting them to heat.
Currently, Green Glue – (Amazon) is widely-known as the most effective damping compound on the market.
By sandwiching Green Glue between two rigid panels, such as drywall, plywood, or medium-density fiberboard…
You can easily create a make-shift sound barrier to cover any area of the room including the floor, ceiling, walls, and door.
When learning how to soundproof a room, decoupling is one of the most commonly over-looked ingredients.
Whenever two structures are in direct contact, sound vibrations can transfer back and forth between each other.
Decoupling is the process of blocking that transfer by creating a buffer between the contact points, usually with some sort of dense rubber, so the vibration is contained to its original source.
Other common examples of decoupling include:
- building a floating floor – using rubber isolators such as the Auralex U-Boats.
- building double walls – which leaves an air gap to help to block sound, and can be made more effective by adding insulation in the open space.
- isolating layers – using resilient channels and resilient sound clips to create a “floating” wall/ceiling.
- isolating studs from the floors/walls/ceiling – by applying joist gasket tape to the studs.
4. Filling Air Gaps
The final task is making sure all the little cracks in the room are sealed up air-tight, so there’s nowhere for the sound to sneak through.
The 3 most common tools used for this task are:
- Acoustical Caulk (Amazon) – which can be used to seal up any cracks in the perimeter of the room. This type of caulk remains soft and pliable, so no gaps open up over time.
- Foam Gaskets – which seal up air gaps from your electrical outlets, window, doors, etc.
- Automatic Door Bottoms (Amazon) – which block the open space between the bottom of the door and the floor.
So that’s a summary of how soundproofing is done professionally. But you might be wondering…
Is All This REALLY Necessary?
As you can see, professional soundproofing jobs require time, money, and skills that most of us don’t have.
So most home studios either skip it entirely, or just do the best they can with limited resources.
Because while outside noises can be annoying at times, they’re usually only periodic, and not constant.
Inside noises on the other hand, such as those from your computer, ARE constant…which makes it much harder to find suitable work-arounds. So up next…
How to Soundproof a Room from Computer Noise
In single room setups, computer noise is a problem that you’ll surely struggle with.
And unfortunately there are no perfect solutions here.
But here are 5 possible solutions that will dramatically reduce the problem:
1. Create Maximum Separation
It won’t completely solve the problem…but creating maximum separation between your computer and mic should reduce the noise to a manageable level.
Besides just increasing the distance, also try:
- Working the angles – by pointing the mic away from the computer, using cardioid mics when possible.
- Dynamic mics – which are less-sensitive to high frequency computers noise.
- Acoustic treatment – especially BEHIND the performer where the mic is most sensitive, so any reflected computer noise gets absorbed.
2. Use a Laptop Stand
When laptops get hot, the fans engage and they get noisy.
With a laptop stand, the computer up off the table, allowing air to flow beneath and keep things cool.
The fans still engage from time-to-time, but not as often and not as fast.
Among the hundreds of models available, here are 3 good ones I recommend:
3. Get an Isobox
The Isobox, pictured to the right, is a high-end rack which solves a number of different problems.
For the noise problem, it has a soundproof enclosure that protects against overheating with a silent cooling fan, and an alarm that alerts you of any problems.
Boxes such as these are the ideal solution for anyone who can afford them, but you can’t, here’s the next best alternative:
4. Build a DIY Isobox
While it may not look as cool, or even be as effective as a real Isobox…
Many people have seen great success by building their own “DIY Isobox” out of plywood and acoustic foam.
For an example of how it’s done, check out this video: (This guy uses it for his guitar amp, but a similar one could be built for a computer as well.)
If you DO try this…HERE IS MY WARNING TO YOU:
Anytime you place a computer inside such an enclosure, it runs the risk of overheating. With your own design, be VERY careful to allow for adequate ventilation, and proceed at your own risk.
Got it? Good.
And now for the final method…
5. Use Multiple Rooms
One of the nice things about pro studios is…
Having multiple rooms makes it easy to keep computer noise far away from your mics.
At home though, the best you can usually do is keep your computer in a nearby bedroom by itself.
Of course, this only works with desktop towers…and many challenges arise when extending computer cables over longer distances.
While no single strategy will work for all rooms, some of the more popular methods people use include:
- Putting your computer in a closet within the same room
- Buying a cable extender that allows you to extend cables to a different room
- Using the Apple Airplay to connect your computer via WiFi to a TV
- Drilling holes in the wall to run shorter cables between neighboring rooms (probably the best option).
So your best bet is to examine the layout of your room, and decide which of these methods will work best in your situation.
How to Soundproof a Room from A/C Noise
The other “indoor noise” that studios often struggle with is their A/C.
If you live in a warmer climate, then you already know how much it sucks to record in a hot stuffy room.
And while you’d think the simple solution would be to just turn off the air while you record…
Once you’ve tried it, you’ll realize how hard it is.
- When it’s ON, you forget to turn it off, and end up with a noisy, but otherwise perfect take.
- When it’s OFF, you forget to turn it on, and don’t remember again until it’s hot-as-hell.
And the constant focus on the air conditioner distracts everyone from the real task at hand. So while it does work, it’s not a long-term solution.
Assuming you’ve again followed the 4 steps to creating maximum acoustic isolation that I showed you earlier for computer noise…and the A/C is still too loud…
Here’s what I recommend:
1. Seal Up Those Cracks
Many folks don’t realize this…but a big portion of A/C noise comes not from the unit itself, but from the world outside.
With window A/C’s, every little crack leaves an opening for sound to leak through.
So make sure it’s sealed up air-tight. And if you must, get a professional to help you re-install it.
2. Remove Those Vents
With central A/C’s, sometimes the problem isn’t the compressor or the fan, but the vent itself.
- Some vents rattle from the airflow.
- Others resonate with certain notes whenever music is played.
So to be on the safe side, remove any vents covering the air ducts in the room.
As a side benefit, this can also provide for more efficient cooling through better airflow, possibly allowing you to run the A/C on a lower setting as well.
3. Build a Sound Dampener
Much like the DIY Isobox we covered earlier, a simple A/C sound dampener can be built with just some plywood, acoustic foam, and a little bit of handiwork.
For an example of what one might look like…
Here’s a diagram I found on the Auralex website that illustrates the concept perfectly:
Now just like every other tip in this post, sound dampeners work KINDA, but not COMPLETELY.
And if the 3 previous tips combined aren’t enough to solve the problem, it could be because your current A/C just isn’t up to par.
So up next, I’ll help you find a better one.
The 4 Types of A/C’s
All home air conditioners fall into 1 of 4 basic designs:
- Portable A/C’s
- Window A/C’s
- Central A/C’s
- Split Ductless A/C’s
Here’s how they compare:
1. Portable A/C’s
Because they’re easy-to-move and require no installation, Portable A/C’s might seem appealing for home recording…
But the truth is…they’re the worst of the 4 options. And here’s why:
- They don’t always cool the room very well.
- They’re surprisingly expensive.
- They don’t dehumidify the room like the other models.
- Worst of all…they’re NOISY.
So if you currently use a portable A/C, I highly suggest exploring other options.
2. Window A/C’s
Compared to portable models, Window A/C’s offer several advantages:
- The outdoor drip dehumidifies the room.
- They’re cheaper.
- They’re less noisy.
I say LESS noisy because personally, every window A/C I’ve ever tried was still too loud for recording. According to some sources though, the newest models have become much quieter.
However, they’re still far from ideal.
3. Central A/C’s
A HUGE step up from window A/C’s, Central A/C’s cool the entire house, instead of just one room.
The biggest advantage of this design is that the compressor is located outside, far away from your microphones…
Which can in-theory, provide an extremely quiet solution to cooling your studio.
The only catch is…the house MUST-HAVE high quality air ducts in order to provide adequate airflow with minimal noise.
And unfortunately, most houses have crappy ducts, and some don’t have any at all.
Luckily, there’s more option…
4. Split Ductless A/C’s
A hybrid between window and central A/C’s, Split Ductless A/C’s are actually comprised of two separate units:
- one for outside
- one for inside
For a studio in need of some quiet cooling, split ductless A/C’s may be the ideal option, because just like Window A/C’s…
- they require no ducts, so installation is easy.
- they only cool single rooms, so they are cheaper than central air.
And just like Central A/C’s…
- the compressor is outside, so there’s virtually no noise inside the room.
While I don’t normally like to recommend specific products unless I’ve tried them myself, if your REALLY want a suggestion on where to start looking, the Mitsubishi MSZ-GE Series Ultra Quiet Air Conditioners look EXTREMELY promising:
Here’s a quote I pulled from the company’s website:
Our indoor units are some of the quietest in the industry, operating at a noise level of as low as 19 dB. To put that into perspective, consider that background noise in a library is 30dB.
One useful tip worth mentioning is: Buy a model designed for a room BIGGER than your own. That way, to keep YOUR room cool, it can operate at a lower setting, and stay quiet as quiet as possible.
Now to conclude this article…
One Final Thought on Noise Reduction Plugins
Because noise is such a complex issue with home recording, some people just give up on the problem altogether…
And instead rely entirely upon noise reduction plugins, which have become increasingly popular in recent years.
But the problem with these plugins is…they can’t remove the bad sound (the noise) without seriously degrading the quality of the good sound (the music).
And they really aren’t meant to. Because originally, these plugins were designed for audio forensics…NOT music.
So the better strategy is to working on eliminating noise BEFORE it gets recorded…not AFTER.
And using your own combination of the methods outlined in this post, you should have no problem doing exactly that.