Recording perfect tracks at home. Part 1: The Room

Home recording is almost ubiquitous among musicians these days. Nearly every serious musician has some sort of recording equipment in his home or within easy reach. And because of the relatively low price of quality recording gear and software, there are a growing number of musicians who have decided to save the money they would normally spend at a traditional studio and buy a home recording setup instead. This gives amazing freedom to musicians, but it has unfortunately contributed to a decline in the quality of the average album as well.

The reason for this decline is a mixture of factors. Firstly, technology has enabled musicians who would not have been able to afford to release an album to do so; and now the market is flooded. Another reason is that people have less patience than in times past for mastering their instruments and their albums are recorded prematurely. But the factor that I want to address here is related to the fact that musicians are not always technically inclined or of the same personality type that recording engineers are. They are looking for quick results to keep their inspiration flowing. They will usually figure out a way to record that gets the job done quickly and on the cheap, but then as they decide to do more with their home studios, they are reluctant to go back and re-learn recording techniques in the traditional method.

My particular area of work is in recording and mastering heavy metal and extreme metal. But 95 percent of what I talk about pertains to all styles of music and all recording situations. You can apply it almost anywhere.

Those that want to convert a house into a real studio with a separate control room and live room can check out books by F. Alton Everest and many other resources online. But this article is actually intended for musicians who will usually set up everything in one room. They often are not trying to record drums and if they do, they will set up the drums in another pre-existing room. Most home studio setups are in a bedroom or other room of this size and they will set up a computer system on a desk and have their speakers directly in front of them on a desk or right behind it. In this series I will address the following subjects: The room, monitoring, the gear, recording preparations, tracking tips, mixing in the computer. Here we go…

The Room:

A typical bedroom or similar sized room will work in most cases. The best sounding rooms that are not custom built are rectangular in shape. A room that is a short rectangle is usually best. Rectangles that are too long have big bass problems in the rear of the room and square rooms suffer from intense standing waves. A short rectangle works best. This is what most rooms are anyway.

All rooms will need some kind of absorption and diffusion. Sound bounces around a room like arrows. Higher frequencies (Treble) are directional. This means that in order to hear these frequencies you will have to be facing the speaker. And treble frequencies also will bounce off of hard surfaces. They will bounce around as long as they have energy. Large rooms have long reflections. This means they take a long time to go from the source (Speaker) to your ears. You will hear a delay. Small rooms make more short reflections and they create what is called Comb Filtering. If you enter a totally empty room and clap your hands you will hear a rapid bouncing of the sound. This is Comb Filtering and it is much more unpleasant than long reflections.

Long reflections are generally nicer sounding to the ear. But there are good long reflections and bad ones. A gymnasium goes not have good sound. If you listen to a sports team practicing in an empty gymnasium, it can be hard to understand what the players are saying to each other. A large church is about the same volume as a gymnasium but it sounds very good. The sound of a church choir is one of the esthetically greatest sounds possible. The reason for this difference is what we call diffusion.

In a Gym, the sound that is bouncing off of untreated walls is allowed to continue to bounce for a long period of time. The reflections add to each other and build energy and volume. In a Church, the different angles and odd shapes in the room stop the sound from bouncing in parallel routes. These odd angles stop the sound from building energy, but the size of the room allows whatever sound does propagate to echo with a pleasant long reflection. So large rooms sound good when they are diffused.

Smaller rooms have no space for long, church-like reflections to bounce. They can only make short reflections. And as we know, an unfurnished small room sounds very bad. So for a small studio, we need to stop those sounds from happening at all. What we use to do this is called absorption. There are many types of products and materials that absorb sound. Some absorb high frequencies only, and some will extend down to the low ranges. Because high frequencies are physically small, we can stop them with porous materials like carpet, foam, blankets and things like this. Bass frequencies are very long, so they take a different kind of material. I will get into this later.

Ok, so we know we need to install absorption materials in our room, but how much and what type do we use? And what about diffusion? Do we need that? Yes we need both absorption and diffusion but we have to be very careful. What we want to do with our room is to allow the longest, good sounding reflections to exist while stopping only the annoying, short reflections we call Comb Filtering. And whatever reflections we do allow to exist, we want to break up like the odd angles in a church do.

Now the first thing we want to do with our rectangle-sized room is to decide where we will set up our speakers and computer console. Will we place our system in the middle of the room with the long ends to our left and right? Or will we place the system in one end of the rectangle?

Really the answer to this depends on your particular situation. You can try both ways to find out what is best for you. There are many technical reasons for using or not using either position, but I will just say that in general, setting up with your speakers and computer in one end of the room is usually best. This keeps the long reflections behind you and allows you set up a commonly used method called Live-End-Dead-End. With this set-up, you will deaden the short reflections around the speakers and diffuse the long reflections on the back wall. Even if you set up with the long ends of the room to the left and right of the control station, you will still absorb the short reflections and diffuse the longs ones. And you will always diffuse the wall behind your head. If the room you have to use is a very long rectangle, you will get a lot of bass problems in the far ends. So here you might want to set up in the middle; even though you will not get great sound, it is more workable than sitting in a bass wave.

Ok, now let’s set up our speakers. In general we always want to be sitting in a position that puts us at equal distance from each speaker in an equilateral triangle. Each speaker will be placed in one of the three points of the triangle and our listening position will be at the third point. Always, this is the proper placement for near-field studio speakers to be set up.

An optimal small studio room is at least 1500 cubic feet in volume (LxWxH). You can go smaller; even 1000 cubic feet is usable but trying to keep it around 1500 or bigger is best. The bigger the room, the more bass you will be able to hear. Rooms under this size don’t have very good bass response. If you plan on mixing, your mixes will suffer if less than 1200 cubic feet or so. If you just plan on recording and having another engineer somewhere else mix, you can use a smaller room.

Ok, once you have your speakers in an equilateral triangle, you can sit down in the listening position and have a friend take a small hand-held mirror and move it on each wall to the side of each speaker. When you can see the speaker’s tweeter from your listening position in that mirror, you will later place a piece of sound deadening material there. Do the same thing on the opposite wall so you will now have a piece of sound deadening material on both side walls. I will talk about materials in a minute.

Now attach the mirror to a stick, hold it to the ceiling and try to see each tweeter from your listening position. Do this directly above each speaker. So you will have two key positions on the ceiling and one on each side wall. Now for the floor, you will need to do the same thing, but the easiest thing to do is to throw a small rug in front of the speakers. And in the case where you have the speakers right on your desk, you can skip the rug.

Another thing I should mention before I get into absorption materials is whether or not you have carpet on the floor of your room. Many American rooms have carpet on them from the start. If you have this, you can deal with it, but its best to have hard wood to start with and then throw carpet down in small sizes as you need it. But if you do not wish to pull out the carpet, this is fine; just use less absorption in the room to compensate.

Ok, the easiest way to get good sound absorption for your side walls and speakers is to buy pre-made acoustic foam from a manufacturer like Sonex, Auralex, etc. A bedroom will probably need about six to twelve 2 foot by 4 foot sheets. You can cut them in half to make 2x2 squares as well. You can start out will less and add as you feel necessary. You can also use blankets or egg crate material but the pro foam is very cheap and works much better so this is what you should do in all cases. The first step is to set up foam in your key positions around the speakers with the mirror. Then we will move on to diffusion and then back to absorption until we get the room to sound coherent.

For the diffusion, we can either purchase diffusers from a company like Auralex or we can use household materials. The pre-made plastic diffusers are excellent. They come in 2x2 size squares and 4-8 of them on the back wall behind your head will be perfect. You can fill them with foam or household insulation and then mount them all to a piece of wood or soundboard. Then place this on the back wall. This will allow the long reflections to exist but not bounce back to hit your head. Without diffusers, when the sound coming from the speakers in front of you is coupled with sound coming from behind you that is coming later, it will phase-out the sound and stop you from hearing clearly. Now with the diffusers on the back wall you should have a tolerable situation. If you don’t want to use pre-made diffusers, you can set up a bookshelf full of books or gather many items of different sizes and shapes and put this on the back wall. A bookshelf or two filed with books is a great, household diffuser. Now you a have dead front end because of the sound absorption and a live but diffused rear end. This is where we get the term Live-End-Dead-End. The rear end is live and the front end where the speakers are is dead.

The next step is to listen to some music we are familiar with in the system. Walk around the room and listen to the sound at a medium to medium-loud level. How does it sound? Is there still too much echo? Ok, now add the other items you will probably store in the room. Add any furniture and other items that you must have in the room. Now listen again. How is it now? In a small room, this may be all you need. If you still are getting too much echo for your tastes, add some more foam to the walls. Try a 2x4 piece on each wall, mid level in about the middle of the room. If you have longer reflections that you want to tame, place foam on the far ends of the room and the ceiling at the far end. If you think it is shorter reflections, put the foam around the listening area more. The more foam you place, the deader the room will sound. More foam is good for clarity but not natural sounding. The best compromise is just enough foam to stop annoying echo and then stop there. I have a medium sized room for my mastering suite and I have ten pieces of 2x4 foot foam on the walls. I have 5 pieces on the wall behind the speakers, 2 on each side wall near the speaker, one on each wall mid way down, a couple pieces on the ceiling and just a couple small pieces on the back wall. I also have a diffuser panel as I described behind my head. My room is 9 feet tall by 17 feet long by 13 feet wide. There are also room ratios that always sound good but for home based musicians, you are always using a pre-existing room so just sticking with short rectangle ratios is all that you need to do.

Ok, now we have taken care of our treble reflections and set up a room that we can listen to music in without strain. The next sound problem we will encounter is bass reflections. Bass is omni directional. It goes through everything. It travels through walls, foam, everything almost. Bass reflections are very difficult to deal with. The bass will always collect in the corners of a room and on the back wall. Because bass reflections are long, you need to be far from them to hear them. And because of this, they will be worse in the back of the room, farthest from the speakers. In custom rooms we can do a frequency analysis and determine where our bass problems are. They call these problem areas Room Nodes and the overly prominent frequencies are called Standing Waves.

If you know where your Room Nodes are, you can build custom made bass traps that are tuned to those frequencies. But for home studio musicians, I suggest foam solutions again. Auralex and others make foam bass traps where the foam is made in a different way, of a more dense design and they work almost as well as custom bass traps. You can fill all your corners with these foam traps. It is not advisable to skip this part of the room treatment. Usually just filling the corners with 8 traps is all you will need to get rid of the worst bass problems. If you have the room, you can also place a couch under the diffusers on the back wall and that can help a bit. If you need more bass trapping, you can purchase cylindrical, mobile bass traps or use the F. Alton Everest books to design a custom bass trap. By the way, buy his books no matter what you do! One is called “The Master Handbook of Acoustics” and the other is called “Sound Studio Construction on a Budget”. Also remember that the most critical part of the recording studio is your monitoring. The room determines how those monitors will sound and how you will interpret what you are recording. An astronomer depends on his telescope and his observatory quality. A recording engineer depends on his monitors and his room in the same way.

If you are setting up your home studio in a room that is not as workable as what I described here, do what you can. Take this information and use it as you can. Buy some books and do some internet searching. In fact, the Internet has all the information you will ever need if you will only take the time to do the research. Recording is an art and a science. If you wish to take the responsibility to do what a recording engineer has dedicated his life to, you will need to do your homework as well so you can at least get the job done without any major problems and record some quality tracks. You probably will still want to send your music out to a professional to mix and master, so this will save you many years of practicing recording; but you will definitely still need to get the basics understood and begin your recording journey on the right foot.

Sound materials:

http://auralex.com/

More extensive acoustic information:

http://www.ethanwiner.com/acoustics.html#diffusers%20and%20absorbers

F. Alton Everest books:

http://www.amazon.com/Sound-Studio-Construction-Budget-Everest/dp/0070213828/ref=pd_bxgy_b_img_b

Determine where your standing waves will be (intermediate level):

http://www.mcsquared.com/metricmodes.htm