~ Or: How Do I Keep The Sound of the Neighbor’s Leaf Blower Out of My Magnum Opus?
Sound proofing and Acoustic Treatment are two completely different animals. COMPLETELY.
As if I’d ever not be overly-wordsy on any given subject.
So back to verbosity.
It’s a topic that comes up a lot. Like, a lot a lot. And the only reason it gets to me is because I spent years hyperfocusing on recording studio construction concepts in a couple of different forums that were run and populated by professionals in that field. Recording studio designers, builders, and operators.
Why? Once upon a time I wanted to build a 3 or 4 room actual recording facility in my garage. Had the whole thing planned out. Knew who I was going to have design it too because while I know some stuff I also know my limitations. It was my “five-year plan.”
Nine years ago.
Fast forward to now. I’ve been studying the theories behind both of the concepts in the title for longer than I want to admit. Acoustic Treatment and Sound proofing. And while I don’t consider myself an expert by any stretch compared to folks like Rod Gervais, John Sayers (RIP), or Stuart Allsop, I’ve learned a ton from them either by osmosis or by asking questions that I had about things that they are experts of.
Which, I sure hope, is enough of a baseline to be able to write at least one blog post on the subject without too much imposter syndrome kicking in and effectively convincing me to be shut up.
On that effusive note, HERE WE GO!
Who Is This Blog Post For?
Before I get started, I think it’s a good idea to point out that there are a wide array of people who might be interested in this subject.
Of course right out of the gate I have voiceoveristers in mind. Maybe it’s because I’m running in that circle quite a bit at the moment but it’s where I see the most activity on the subject. Voice actors want “sound proofing” in their home studios. Of course, right? Because the airplane going by above or the nearby garbage truck rattling the floor below can ruin a take or terminally disrupt an entire session. So getting those things OUT of the recording environment is something that they want to be able to do.
Musician and audio friends of mine are also interested in this subject. For the session musician, you want as silent a recording environment as possible for your acoustic instrumental recordings. For the mixing engineers, having a room that is free of irritating ambient noise is critical to getting a decent-sounding final product. The solution? “Sound proofing.”
Casters of Pods
Unsurprisingly, this is a topic of high interest for podcasters as well. I’ve heard many a podcaster wish that they could find a way to get the “room sound” out of their podcasts to sound like other podcasters who do not have room sound in their podcasts. While I’m more a proponent of “don’t let these things stop you from creating,” I understand that level of envy. There is a desire of quality that is being established and for some, that level makes them feel more comfortable with their stuff. I get it! So podcasters are in on this one too.
Who else? Instructional content creators. People who build and design educational programs for anything from “How To Crush LinkedIn And Get Clients” to “Follow These Steps To Build A Web Page From Scratch” to “Macrons Are Delicious: Here’s How To Make One. You’re On Your Own For Six.”
Pretty much anyone who wants to record a thing and record only the thing. Not the leaf blower, not the semi air-braking down the street, not the dog next door, not the kids.
So now that we’ve established that, let’s talk more about what on earth this is and why.
What is Acoustic Treatment?
I’m going to come back to sound proofing in a bit. Acoustic Treatment is a topic of baseline importance in this instance because it’s going to come up in both categories. So let’s start here.
Acoustic treatment is what most ordinary people THINK they want when they ask for soundproofing. When they want to know which foam is best for “sound proofing”, this is what they generally have in mind. Why do I say that? For a few reasons:
- There is a misconception that foam/insulation/stuffing/panels/egg cartons* are sound proofing. They are not.
- With the misconception that those things are sound proofing comes the melding of terminology to intent, and the idea becomes “foam can kill off external noises.” It cannot.
“But George,” you besnivel, “why you gotta be so down on people? They’re just trying to learn.”
To which I would respond …… ok, that’s a fair point. It’s also partially why I’m here. My goal at the end of this is to have learned you, the reader, as much as possible about the subject.
* egg cartons are useless. more than useless. they might actually do more harm than good if your goal is to do anything about the sound in your room. anyone who says otherwise is TRYING to be really helpful but unfortunately, they’re not. egg cartons should be in the fridge. with eggs in them. to make delicious egg things. sorry vegan friends.
So the answer is:
Acoustic Treatment is Sound ABSORPTION in most cases. Not sound proofing. What all of those acoustic panels are doing on your walls is absorbing sound so that it doesn’t bounce around like Flubber.
That’s right, bounce.
Let’s get a teensy bit technical for a second.
The room that you are sitting in right now is probably illuminated. To some extent. Even if it’s in the dark and you’re staring at this on your smaller screen – hopefully in dark mode – something is happening. The light of your device or the lights in the room are efflorescing illumination. When you turn on a light switch, a light source activates and all of the things in the room brighten up. Why is this? Because light bounces off of all of the surfaces and reflects and propagates as a result. This is something that waveforms do.
Light is waveforms.
Guess what else is a waveform? Sound. Sound bounces like a baby boy off of every flat surface. Some surfaces create more bounce than others. If you are in a bathroom and you start belting Whitney Houston in the shower, it reverberates like crazy and makes you sound AMAZING. If you’re in a home theater of some kind with those acoustic ceilings and panels on the walls, it sounds a bit more “dead” of reverberation in comparison. A recording studio control room? Dead as a can of spam.
Which one of those environments would you suspect is the better one of those for getting a clean recording of something? The shower or the movie room?
If you said “movie room,” you’re correct!
How does that work?
While there are things that cause sound to bounce around like crazy – flat surfaces, tiled walls, church domes – there are other surfaces that will actually absorb or attenuate sound. Thick layers of clothing. Insulation. Very thick foam. These things cause sound to not be able to bounce as easily. Most of the acoustic panels you see in a studio or a movie theater or a recording room are very often 4″ thick layers of insulation of some kind with a cool looking fabric to cover the fact that it’s 4″ thick layers of insulation of some kind.
Sound waves will enter one of those panels and find themselves dispersed and filtered out before having a chance to bounce off the wall behind it and return to the room, causing a deader sound than before.
Wanna know something super witchcrafty? If you put that same acoustic panel a few inches away from the wall behind it, it gets DoUbLe DuTy!! A sound wave will filter through the panel on the way through it. What is left of it will bounce off the wall behind it. And then it will enter the acoustic panel again and attenuate even FURTHER. If the panel is touching the wall, it only filters once.
Not exactly insane. More physics. But I’m also cognizant of allergies so I won’t get into too much math and science here. For the sake of avoiding a sinus infection, let’s just assume that a sound absorbing panel a few inches away from the wall will do exactly what I said it would.
So the solution is to just put up a bunch of treatment panels on walls and call it a day, right?
Except when you do that, why do you still get that reverb sound off the walls you THOUGHT you just treated?
There’s a BIT more to it.
Two more things to consider
Thing number one: when treating a room to eliminate soundwaves bouncing off of surfaces, very frequently there is a spot that is skipped.
That’s right. The thing way up there that has lights in it (which generate light waves that bounce off all of the things too, remember?) and probably nothing else. One giant flat surface just WAITING to receive a sound wave and kick it right back at you.
“But George,” you bewhinge, “shouldn’t all those panels I just put up on my walls take care of that?”
To which I would respond “No. Duh.”
But then I’d elaborate because I’m only so mean.
A microphone will not lie to you the way your ears will. Your ears can stand in a room of bouncing soundwaves and think it sounds great. Why? Our brains trick us. They tend to filter things out that we don’t want to hear. Room reverberations. The way a guitar amplifier actually sounds. When the kids are in the back seat saying “NO!” “YES!” “NO!” “YES!” “NO!” “YES!” “NO!” “YES!” “NO!” “YES!” to each other and then SWITCHING to see how long they can go at it before you crack.
Microphones hear EVERYTHING. So if the ceiling is untreated and a sound bounces off it, it will hear it.
Get something up there.
Even my voiceoverister friends who record in walk-in closets packed to the gills with clothes: if there’s still a sound coming from SOMEWHERE, it’s probably the ceiling where no cloth exists.
So that’s Thing One.
That leaves Thing Two
The other thing that needs to be considered is corners.
Yes, the thing you stand in when you’re in trouble. You’re not in trouble right now but I encourage you to go stand in a corner and speak out loud.
Go ahead. I’ll wait.
It probably sounds …. different, doesn’t it? Even your ears can’t entirely lie to you on this one. If you get close to a wall and talk at it, you’ll hear yourself coming back at yourself pretty easily. A corner? It AMPLIFIES that sound and adds things to it.
An untreated corner will take a sound and do weird mathy things to it and cause for a buildup of frequencies bouncing into each other in that small space. Moreso the closer you get to the interior of the corner.
Without getting TOO technical, the solution to a corner is called a “Bass Trap.” Lower frequencies like to build up in corners quite a bit so many recording areas will have triangular-shaped towers of insulation that absorb all those sounds and solve the problem.
Do you need to fill EVERY corner of the room and cover EVERY SQUARE INCH of the walls and ceilings with something to absorb?
Probably not. Good coverage is necessary but it’s not going to require complete and total an-echoic slathering.
Ok. ALL OF THAT to get to the other half of what this is all actually about.
What is Sound Proofing then?
Sound proofing is …. exactly that. Making an environment where external sound cannot enter the interior of the recording space.
I’m going to try to make this as simple as possible without being silly. Here goes.
Think of the most central room of your house. Like a coat closet or a laundry room or a walk-in closet. If there is a noise outside like a dog barking or a leaf blower or a truck going by, the interior of one of those rooms is probably going to hear it less than if you were standing next to the front door with just a few inches of drywall and insulation separating you and the outside world, right?
We’ve already answered some of the question.
Density and distance and reduction of the opportunity of soundwaves to travel. All of the stuff in the house between the outside walls and the interior of those spaces further in block the potency of those sound waves.
How that theory applies to sound proofing
So sound proofing itself is not entirely different from that, except it goes an extreme step further.
We’ll use the example of a single sound-proofed room as an outline of how this works.
It is often referred to as the idea of a “room within a room.” If you have a large space to work with, what you end up doing is building a smaller room that is not connected in any way shape or form to the frame of the building you’re in. Have a basement with high ceilings? Great!
You would build a framed room that is not actually attached to any of the existing walls. And not attached to the ceiling joists above if you can get away with it. Fill the gap between the new room and the old wall with lots of insulation. Seal every square inch of BOTH LAYERS of drywall inside with caulk. Build a door that honors that gap.
Viola! You have the makings of a sound-proof room!
(for those of you who know what I’m talking about, I’m glossing over floating floors and ceiling decouplers and green glue because this post is already too long)
But wait! There’s more!
Ok, so you have worked with a designer and maybe even a contractor if you’re not handy and you have a room that adheres to the concept of sound proofing.
So WHY DOES IT SOUND LIKE A BATHROOM????
Guess what? You have untreated walls, ceilings, and corners. Again.
So. EVERYTHING that I said up above about acoustic treatment? All of that applies to this room. Panels on the walls, ceilings, and corners.
What you have NOW is Actual. Bonafide. Sound Proofing.
And proper sound absorption.
Tell that neighbor with the leaf blower to do their thing. Scoff at the dog that won’t be shut up every time a blade of grass dares to bend to the wind.
TELL THEM TO DO THEIR WORST!
So why doesn’t everybody do this then?
Well. Sound proofing is expensive.
As you saw, it requires building something. Building quite a bit more than some frames to house insulation to hang on the wall. You need to build an entire room. And it needs to be more elaborate than just a regular framed room. Just building a regular room by itself is already costly. Have you seen what a 2×4 costs right now? Multiply that by …… more. It adds up REAL quick. 2x4s, 2x the normal amount of drywall, insulation, framing, maybe even glass, and on and on and on.
OR. Purchase a large-scale Studio Bricks room. Those work REALLY well.
FAR less expensive. Yes, some material costs. Or pre-built if you don’t want to dig up the table saw.
Ultimately, far less expensive. And if you do not have nearly as many ambient sound concerns as I’ve outlined above and you don’t need a sound proof environment? Avoid the expense and heartache at all costs!
What are some alternatives?
If you NEED a space that is sound proofed sporadically for projects? Consider renting a location when the need arises. I’ve suggested this to some of my voiceoverister friends who audition from home. If a big gig gets booked and you need several hours of silence in a row, book a studio. It’ll be worth it.
If you’re in a network of musicians or actors or other folks who do this kind of thing, talk about trading skills. And spaces. Or cost-sharing, even.
Ultimately, do the best that you can with the space that you have and do what you must with it. If it’s not sound proofed, make it sound as good as you possibly can. And when the big opportunity comes up, chances are it’ll offset any sound-proofed space rental expenses in the long run.
And when you do make it big, get a local studio on retainer or hire someone to design a sound-proofed space in your living quarters. Or buy a prefab double/triple-walled construction. They’re out there and easy to find and only cost you as much as a house in some areas of the Midwest.
The end! I think.
So there we have it. Sound proofing and acoustic treatment are two completely different animals.
One makes the space that you are in sound better than it would otherwise natively.
The other removes all of the external sounds from your environment but STILL requires the former to be complete.
My mission is, as best as possible, to help eliminate that confusion so that when a person who needs a thing needs a thing, they know exactly what they need and what to ask for to avoid any possible misunderstanding.
If you have any further questions, PLEASE feel free to let me know. If it gets to a degree that I cannot answer the question, I know a LOT of people I can refer you to.
Thanks for hanging in for this excessively long explanation of a confusing topic!
Until next week.
-= george =-