It’s funny how you never realize how noisy the world actually is…
Until you build your own recording studio.
All those background noises that you never really noticed before…
Suddenly become painfully obvious when heard through a quality condenser microphone.
Which is why, one of the first questions beginners ask is:
How do I soundproof my room?
And so for today’s post, that’s exactly what I intend to answer.
Let’s begin. First up…
What Soundproofing does NOT do
Often times, newbies mistakenly ask about soundproofing, when what they really mean is acoustic treatment.
So real quick…just to clarify:
- Soundproofing makes your room quieter, by blocking-out external noise, while…
- Acoustic Treatment makes your room sound better on a recording, by absorbing excessive ambience.
And ideally, any recording studio 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 sessions.
- inside noises stay inside, and don’t disturb your neighbors.
But until you’ve recorded in a room that ISN’T soundproofed, you probably don’t realize how much noise actually exists. For example:
- Common outside noises include: people, traffic, weather, and plumbing.
- Common equipment noises include: computer fans, hardware racks, and air conditioners.
- Common impact noises include: footsteps, and anything else making contact with the floor.
And all of these have the potential to ruin your recordings. Later on in this post, I’ll show you how to handle those inside noises…
But first let’s tackle the outside noises, using…
The 4 Methods of Soundproofing
The process of soundproofing a room is accomplished using a combination 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 that room require lots of mass…which prevents 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.
But to add mass to an existing room, additional structures must be built using materials such as mass loaded vinyl, aka Sheetblock – (price/reviews), 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 better because it measures isolation in dB at specific frequency bands…
While STC uses just one number for the entire frequency spectrum, which can often be misleading in terms of actual performance.
Similar to adding mass, damping is a method of soundproofing that dissipates kinetic energy from sound waves by converting it to heat.
By sandwiching Green Glue between two rigid panels, such as drywall, plywood, or medium density fiberboard (MDF), using two tubes for every 4×8 ft sheet…
You can easily create a make-shift sound barrier for your studio that can be added to any area of the room, including the floor, ceiling, walls, or even the door.
Whenever two structures in your room are in direct contact with each other…
Sound vibrations from one can transfer freely to the other, making the original problem even worse.
Decoupling is the process of blocking that transfer of sound by isolating the contact points, usually with some sort of dense, pliable rubber.
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.
Using a combination of these techniques, any type of resonance that develops in the room can be contained to its original source, instead of amplified by the surrounding surfaces.
4. Filling Air Gaps
The final task of soundproofing is to make sure all the little cracks and holes in the room are sealed up air-tight.
Because even after completing the first 3 tasks, any open spaces still offer an easy passage for sound to sneak through.
The 3 most common tools used to plug up those holes are:
- Acoustical Caulk (price/reviews) – which can be used to seal up any cracks in the perimeter of the room, or any small holes that may exist elsewhere. 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 (price/reviews) – which block the open space between the bottom of the door and the floor.
And that’s a basic summary of how soundproofing is done.
Now at this point, you might be wondering…
Is Soundproofing REALLY Necessary?
As you can see, soundproofing a room is a huge job which requires time, money, and skills that most of us simply don’t have.
Which is why most home studios either skip it entirely, or just do the best they can with limited resources. And that’s totally fine…
Because while outside noises can be annoying at times, they’re usually periodic, so you can still find those quiet hours during the day to work in peace, even with no soundproofing whatsoever.
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 Keep Computer Noise Off Your Recordings
These days, with single-room-setups being the norm…
Computer noise is a problem that plagues virtually all home studios…
Since microphones and computer are now forced to co-exist in close proximity.
If this is a problem you currently struggle with…
Here are 5 possible solutions that I suggest you try:
1. Create Maximum Acoustic Separation
While it won’t completely solve the problem…
Creating maximum acoustic separation between your computer and mic can at least reduct the noise to a manageable level.
Here’s how it’s done:
- Increase the distance – by putting your computer at one end of the room, and your mics at the other.
- Work the angles – by pointing the mic away from the computer, using cardioid mics when possible.
- Use dynamic mics – which operate at lower gain settings, and are less-sensitive to the high frequency noise of computers.
- Use acoustic treatment – especially BEHIND the performer, where the mic is most sensitive, so any reflected computer noise gets absorbed. Reflection filters are a good option to try as well.
If these tricks alone aren’t enough to solve the problem, up next…
2. Use a Laptop Stand
The fact is: when laptops get hot, the fans engage and they get noisy.
So a great way to keep your computer cool is to use a laptop stand…
Which elevates the computer up off the table, allowing air to flow beneath.
The fan still engages from time-to-time, but not nearly as often.
And considering the low price of an item such as this, the investment is well-worth it.
3. Get an Isobox
The Isobox, pictured to the right, is a high-end rack that solves a number of problems that standard studio racks don’t address.
To tackle the problem of computer noise, it has a soundproof enclosure that protects against overheating with a silent cooling fan, and an alarm that alerts you in the event of any problems.
As you might guess, the Isobox is extremely popular in high-end studios…as it is perhaps the ideal solution for anyone who can afford its incredibly-high price tag.
For those who can’t afford it, here’s the 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 Keep A/C Noise Off Your Recordings
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 to 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.