One of the hardest things for new voice talent to overcome when they have little to no experience with sound isolation, acoustics or audio recording, is how to get the audio they do record up to standards that would be acceptable for professional production. Many times beginners will pout and cry about how they never get hired or booked for a gig without looking at one of the core reasons, outside of professional training, why they don’t. That reason is how the product they so desperately want to sell sounds.
If you took the greatest voice talent in the world and forced him to record his stuff in a bathroom, no one would ever hire him. Why would you? His audio would stink.
Though daily, many people wander out into the VO world with audio that sounds like it was recorded in their bathroom – and they wonder why it is they have so much trouble.
One of the first things we have to do is get these people to a point where they can hear when their audio is poor, and then teach them how to correct it. An easier solution in the beginning might be to improve their audio from the start, which in turn would enable them to better understand when it’s not so good. I have long felt that you will never know the true enjoyment of Foie Gras until you realize you’ve been eating crap all this time.
We will attempt in this article, to explain some of the very basic principals and methods one must employ in order to improve their audio. Hopefully the rest will take root from this exorcise and grow on it’s own.
We start off with an empty room, or at least as empty as it can be.. Funny thing is more junk in the room (as long as it’s the right kind of junk like sofas, curtains and book shelves) can actually help you when it comes to dealing with unwanted room reflections. In an empty room with bare walls and no carpet, there is nothing to dampen or prevent existing audio waves from bouncing all over the place and the echo is abysmal. Our strategy here is to add absorptive and diffusive elements to the room to increase the decay rate of those waves and eliminate opportunities for them to build up or “stand” in the room.
Combined with strategic microphone placement, we should be able to eliminate at best, or at least greatly attenuate echo or “room boom” in our recording environment. So before doing anything, get some carpet and padding in the room you’re thinking of recording in. One of the biggest reflective surfaces in your room is the ceiling and we want to null that surface by applying treatment (carpet and padding) to its direct opposite (the floor).
One of the members of the local VO community has a recording environment similar to this one in the sense that it has very little in it when it comes to furniture, and the furniture that is in the room is mostly hard surface. Also, the room they record in is more rectangular than square, which serves as a benefit because the worst thing you can have is a perfect square where all of the surfaces are directly reflective of one another. Square rooms require more treatment and are much more of a hassle when it comes to waves building in the room.
Seeing as how a square room is the worst – we will deal with a square room, but realize that the following concepts and solutions can be applied to any shape room. In theory, the more odd the shape of the room, the easier it is to treat.
Also realize going into this; acoustics is an exceptionally complex science and as with any other; if you want precise, predictable results you need precise measurements, methods and study. None of what is discussed here equates to an example of that precision. These methods are broken down so as to be simple and can be applied by anyone as long as they follow the basic concepts discussed in this article.
Our member has a microphone placement similar to position #1 or #2. Ultimately they would be better off with placing their microphone in position #3. But before we just pick up our microphone and plop it in the middle of the room, let discuss why we don’t want positions #1 or #2, and cover the advantages and disadvantages of position #3
Position #1 is the worst of the three. It has not 1 or 2 or 3, but potentially 6 or 7 different reflective surfaces all within a few feet of the microphone. You have to add the walls in the corner, the ceiling above the microphone and the table below it, plus the return reflections from the wall on the other side of the room.
There are just too many surfaces to deal with whether or not they may be treated. It is a poor place to put the microphone no matter what. Oddly enough, a lot of young talent after hearing about “booths” will by default choose the most booth-like area of the room to record their audio in.. Funny, but many people start this way with all the best intentions figuring if they don’t have a booth they might as well put their stuff in half of one rather than nothing at all. It is just a poor choice, but not one that is irreversible. The only thing that is irreversible is the audio you record with a microphone placement like this. Even the most skilled editor cannot edit out the reflective artifacts caused by such a setup..
Position #2 is still a bad choice, just not as bad as the first. If you set up your microphone at position 2 and faced the corner (or stood with your back to it) you may be dealing with less reflective surfaces than position #1 but the three primary surfaces (both walls and the ceiling) all reflect directly back at the microphone and worse; the three reflections all meet right at the microphone at some point. It would take far too much time to try to correctly explain what happens to sound waves when they meet in a select area of the room and the microphone happens to be in the middle of that area, but it is safe to say all of the audio signals meet, intertwine, distort, reverse phase and null in these locations, accenting certain frequencies over others.
Welcome to the wonderful world of standing waves or room modes.
There is no need to go into the mathematics behind it because it gets very complex and isn’t the purpose of this article. If you have some free time and want to realize why you stunk at math in school – there is no shortage of information about the topic on the Internet. You should however understand them and how they affect the product you are trying to deliver so that when you set out to treat your room you understand why you are doing it. That understanding will at least help you explain to your friends and loved ones what all the funny stuff on the walls is for.
One other note:
We aren’t talking about trying to achieve orchestral acoustics here. We are dealing with one person, one speaking voice and one room. We will not be recording opera in this room. We’ll be recording the speaking voice. There is a tremendous difference in the requirements of the two. Our goal from the outset is to “deaden” the room and make it so that it isn’t as reflective as before. In studios where music and vocals are produced, it is often important that the room has a little more life, or is a little more reflective. For voice over we don’t want a reflective room.
So lets look at microphone position #3. In an empty, square room, this is probably a worse choice than the other two if the room remained untreated with no carpet. But when the room is treated properly – slight modifications from center – to the placement of the microphone will more than likely garner some good results for us. We are going to start with some of the wall treatment in the following picture – assuming from this point forward that the room has now been carpeted.
Here we have the talent (1) standing with their back to the upper left corner facing microphone position #3. On the wall to the right of the talent (your left) is our first acoustic treatment. It is foam acoustic material from Auralex. (The funny little bumps are my best artists rendering of the foam from overhead) Simply treating this wall and calling it a day would be far from adequate. There is a lot more work to do.
This foam should cover roughly 85 to 90 % of the open wall space from floor to ceiling. What we really want to do is see that it extends above the height of the talent and down below the waist. Somewhere around the knee or calf high should be adequate.
You may have noticed the treatment on the wall somewhat mirrors the outlined shape on the opposite wall, which in this plan is actually a window. It could be anything really. What I want you to notice here is this is going to be a reoccurring theme; when one wall is reflective, we want to make its opposite wall absorptive and diffusive, which we will cover as we go into this further.
If the room you are working in doesn’t have a window on the opposite wall you would apply combinations of materials to the wall where the window is in this drawing. You will see an example of this technique used on a different wall, a little further down.
When the walls of the room are left untreated, sound waves are left to reflect off untreated surfaces and bounce all around the room, grouping in different areas until they dissipate, or “decay”. When speaking into the microphone at position #3, all of these reflections will eventually make it back to your microphone and into your audio signal as echoes. This process takes milliseconds and will seriously color your audio to a point where it is unusable for professional production.
What we accomplish by treating the first wall with foam and covering the opposite window with the heaviest drapes we can afford, is a dead zone, or less reflective zone in the area that has mirrored treatments applied to it.
But we are still left with the other walls and reflective surfaces in the room, which will be just as active as before
Given just the treatment of the first two surfaces though, the most likely positions for the talent to address the microphone would be positions B, C, E and F.
It isn’t at all adequate to only treat 2 sides of the room and it is wrong to look at it as solving “half the problem.”
You really need to treat all the surfaces in the room if you want the best results.
When we talk about Absorption, we are talking about any material that absorbs audio waves or attenuates certain audio frequencies. These materials can be anything from acoustic foam to blankets, movers padding or furniture wraps, pillows, egg cartons, cork, corrugated cardboard, home insulation to ceiling tiles. The foam however is the most effective and certainly the most esthetically appealing. Many solutions out there equate to nothing more than acoustic “wish-craft” and are poor choices of expenditure and effort and are wholly ineffective. If you do buy acoustic material, buy if from the company mentioned in this article.
One of the things that can be a little confusing for people when buying foam is that it comes in varying degrees of thickness. Here is how to understand the difference. The thinner the foam, the higher frequency sound it was designed to attenuate. One-inch foam is for higher end frequencies and general reflections, and two-inch foam or larger is for more specialized needs. Most of you would be able to get away with one-inch foam, though if you are a deep, baritone voice, you may find that a combination of 1 and 3-inch foam around your room is needed to help you calm a broader range of frequencies.
Low-end reflections are not to be ignored and can color an audio signal as well, so Bass Traps might not be a bad idea but may be excessive for some. It is best to work incrementally and treat a problem once you know you have one rather than buy too much material up front. Most of these companies won’t take the stuff back and I can’t say I blame them. If you do end up with some extra – just find a place for it. I have never heard of a voice over room that was too dead.
When we talk about diffusion, we are talking about any smaller reflective surface in the room that breaks up or redirects room reflections. This can be done with materials meant solely for this purpose, or done unintentionally by other objects in the room that lend to the diffusion of audio waves. Auralex sells diffusers, usually under the name “Mini-Diffusers” and they are quite effective at scattering sound in all directions. Scattering the waveforms aides us in our mission by keeping them from building to great intensity in any one location in the room. The use of diffusers is essential in our quest to quiet unwanted room reflections.
Now we will begin to apply treatments to the other walls and see if we cant quiet this room down a bit. What you will see in the following drawing is an example of alternating treatments between two opposing surfaces. Diffusion is placed across from absorption in as many locations as possible. What we want to do is use diffusion to scatter any early reflections, and absorption to pick them up and keep them from once again returning across the room. Diffusers decrease their strength, and the absorption swallows the weaker signals up.
When ever you apply treatment to one wall, look at the opposite wall and consider how you would hang an opposite treatment on the opposing wall. In areas where two diffusive or absorptive treatments must face one another because of room shape or design, what we would like to do when ever possible is apply the same treatment to opposing walls in direct negative relation to one another, though this is not always possible, as in the room with the window.
Think of it in negative using the following example: If you hung a large circle of foam on one wall and cut a smiley face into it, in the exact same location on the opposing wall you would hang the eyes and the mouth you cut out. Overall, by applying process after process, we will eventually eliminate or at least greatly attenuate, room reflections to a level where they don’t end up in our source audio.
Going back to the above drawing, you will see that we have demonstrated two new microphone placement options that are removed from the center of the room. In a square location, the center is always going to be the worst place to put a microphone no matter how much we have treated the room. With the room treated like it has been in this design, we can move the microphone into off-center positions and have the talent address the microphone from three possible “optimum” locations.
As with anything, some experimentation is required to fine-tune the optimum position. What we don’t want to do is lock the talent in one location. The talent should have a little freedom to move around and not have their sound be effected unless they truly wander “off-mic”. Your results may vary.
Realize that this type of treatment will only deal with the liveliness of the room and the reflection, diffusion and absorption of audio once it enters the recording environment. It will do nothing to prevent sounds from entering the area where you record. This type of treatment though, when combined with quality equipment and aggressive sound isolation techniques, will greatly increase the quality of your voice over audio. Even as a stand alone fix, with little done to isolate your room from unwanted noise, you will still find this type of treatment will take you light years ahead of the product you could produce without it.
Good luck.. Get out there and get some good sound…
MM
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