PLEASE NOTE: This article has been archived. It first appeared on ProRec.com in May 1998, contributed by then Editor-in-Chief Rip Rowan. We will not be making any updates to the article. Please visit the home page for our latest content. Thank you!
I admit it. I’m a homereccer.
My wife barely remembers what I look like. My non-musician friends don’t remember me at all. Good thing I don’t have any kids or they’d be in a one-parent household.
My dog, bless his wagging tail, still loves me. Even when I run him out of the studio.
The studio consists of three adjacent rooms. The first room is the control room. This room houses my computer recorder, mixer, my old metal rack of effect units, speakers, and a few chairs. The control desk faces out over four windows, each of which has a heavy drape that can be drawn.
The second most important room is the bathroom. Besides serving obvious biological functions, the bathroom also doubles as a vocal booth. It has tile walls and a somewhat heavy bathtub curtain. When the curtain is drawn, the vocals recorded in it take on a nice resonant quality from the tile walls (without the curtain, consonants are too harsh). This resonance serves two functions. First, it’s a great vocal effect in many occasions that simply sounds better than any digital effect… because it’s real. Second, and maybe more importantly, it makes vocalists very comfortable. What is more natural than singing in the shower?
The third room is the tracking room. This room is L-shaped and is big enough for a whole band. However, I rarely ever use it. It seems that for many activities I wind up recording in the control room. For tracks that I would use the tracking room, I inevitably wind up using my living room. The living room has hardwood floors and a nine-foot splayed ceiling, which provides a great natural ambience. I have recorded some most excellent guitars in that room.
The most significant drawback in my studio as well as most home studios is the 8 foot ceiling and smallish rooms. A good studio will usually have at least one large room with a high ceiling. For example, my good friend Ben Blank in Austin has a great tracking room with a 13 or so foot ceiling, wood floors, and reversible accoustic tiles on the walls. The tiles are quiet on one side and live on the other. In about two minutes he can take the room from dead to live or anywhere in between.
Anyway, enough of these ramblings. I came here to discuss some principles of home studio design and improvement.
Soundproofing is critical for two reasons: to keep inside noise inside, and to keep outside noise outside. Most newbies to recording are mainly worried about the effect that the Marshall full stack is going to have on the neighbors and overlook this critical second point. When you’re first getting started with a 4-track and an SM-57, unwanted outside noise is usually not an issue. As you progress into more advanced microphones, more powerful preamplifiers, quieter recording media, and powerful compressors, you find that those pesky cars, airplanes, birds and leaf blowers make their way onto many a track. In fact the lead-off song on my band’s latest CD features a guest appearance from my dog. The bark is barely noticeable – you have to know where to listen – and it doesn’t show through over the radio, only on the CD. But it’s there, and I laugh (and cringe) every time I hear it.
Whatever you may have been told, you cannot soundproof with Sonex tiles or any kind of foam or carpet. Foam is used for accoustic treatment (reducing reflections), NOT soundproofing. It simply will NOT have a significant effect on the transmission of sound into or out of your studio.
Soundproofing material must be ISOLATED, AIRTIGHT, LIMP and DENSE in order to effectively reduce sound transmission.
– Isolation: Sound moves quite well through many barriers, such as drywall and plywood. Adding a layer of plywood to an existing wall will increase the mass of the wall and thus slightly reduce transmission of sound. Adding an isolated inner wall of plywood DRAMATICALLY reduces sound transmission. Why the difference? In the first example of adding a layer of plywood to an existing wall, the tight coupling between the plywood and the drywall easily transmits the sound. There is no “cushion” to absorb the vibrations of the plywood and prevent them from traveling directly through to the drywall. But in the second example, even a 2 inch airspace between plywood and drywall can reduce sound by up to 20 db. Now the sound has to activate the plywood, which vibrates and activates the air column, which must then activate the drywall. Note that connecting the plywood to the drywall – even with wood studs or braces – couples the walls and greatly reduces the isolating effect.
– Airtight: Even a small hole in a barrier, such as a hole cut to provide access to an electrical outlet, can render the barrier useless. A one-inch square hole cut into a 100 square foot barrier reduces its sound blocking capability by about 70%. Therefore it is critical when applying barrier material that you achieve an airtight seal to the best degree possible.
– Limpness and Density are the critical determinants of a material’s sound reduction qualities. If a material is limp, it does not spring back easily and thus resists vibration. Dense material is massive and thus requires more energy to activate it. Lead sheeting is widely considered to be the most effective soundproofing barrier material. At about 1 pound per square foot – and extremely limp – lead sheeting can be an excellent choice for the person who is serious about soundproofing. Particle board is denser than plywood, which in turn is denser than drywall.
2. Reverberation (Reflection) Control
This is where Sonex foam comes into play. These foam eggshell treatments we’ve all seen can help to reduce reflections in the room. For this reason they are very useful in a rehearsal area because by reducing reflections they reduce loudness, and therefore make long rehearsals easier on the ears and brain. Sonex is not great material for widespread treatment in studios. The reason is that even the thick 2 inch foam cannot control bass frequencies. It takes six inches of foam to damp even midbass, and it would take over a foot of foam to damp low bass. Therefore if you apply Sonex foam all over your walls and ceiling, you’re blocking upper-frequency reflections but leaving the low-frequency reflections. This causes the room to sound “dead” or “dark” and can really suck the life out of your mix.
See, reflections aren’t bad per se. UNCONTROLLED reflections can be bad. What is desired is a way to scatter the reflection randomly about the room. One of the best tools to provide useful, dispersed reflections is a sound treatment tool known to accoustic specialists as a bookcase. An 18-inch bookcase, stacked randomly with books, not overpacked, is the best room treatment money can buy. And, it’s a great place to put books. Put some of these around the room, typically in the center of blank wall space, and listen to your room now. It won’t sound dead – but slapback and harsh reflections will be gone. Because it has an irregular surface and deep cavities, a bookshelf is capable of absorbing much lower frequencies without deadening the room.
Now, you can’t put a bookshelf on the ceiling. Here’s where a little plywood and sonex tiles can work wonders. Take some pieces of plywood, put some Sonex on them, and suspend them from the ceiling at irregular intervals and heights. Just a few will do the trick. Again, the point isn’t to kill all reflections, just to tame the harsh ones.
When you get the reverberation thing down, you’ll be the talk of the engineering community. Everyone will be wondering what effect you used to get that “live” sound you got. You’ll just smile knowing it’s the sound of your room, a sound nobody else can go out and buy.
Why is it that we will spend tons of money on all kinds of gear and then try to do a mix with headphones? The speaker is the most important tool in getting a proper mix – I’ll say even more important than the microphone. With good speakers you can make adjustments to make a half-assed mic sound good. With bad speakers you’ll make adjustments so that even the best mic sounds bad. Headphones are even worse than speakers. Why use speakers instead of headphones?
– Imaging. Stereo sound consists of four sound arrivals: L speaker to L ear, L speaker to R ear, R speaker to L ear, R speaker to R ear. With headphones, you get only 2 sound arrivals: L phone to L ear, R phone to R ear. So instruments that sound well-placed in headphones may very well NOT sound right in speakers. Unless you’re creating a binaural mix (a special mix designed only for headphones) you’ll want to make sure your mix sounds good on speakers.
– Phasing. Take a simple bass tone and put it into each speaker. Each cone moves out together, increasing pressure in the room, and then in together, decreasing pressure in the room. Now reverse the polarity on one of the speaker terminals – while one speaker is moving out, increasing pressure, the other is moving in, decreasing pressure. The net pressure in between the speakers is always zero. This is out-of-phase or cancelled bass. All stereo signals contain some out-of-phase material which determines the “space” of the mix. Since the sound coming out of speakers mixes in the air before hitting your ears, out-of-phase sounds will cancel before they reach the ear. With headphones, the phasing problem is only in your head. Each ear hears the whole signal. This can confuse the brain and can make a mix sound very different through the phones than through the speakers.
– Frequency Response. Bass is heard through the ears, head, chest, legs, feet, and seat (that’s your ass). High frequencies are heard by the ears and through the base of the skull. Clamping phones onto your head basically starves several sound receptors of information. You need that information to do a proper mix. Moreover, the ears use a sensitive comb filter to accurately determine the location of sound. This means that certain frequencies are cancelled by the ridges on your outer ear before they are reflected into the ear canal. Each person’s outer ear is different and each person’s brain is tuned to the shape of their own personal filter There’s no way to shoot sound right down the ear canal (as with headphones) and not screw up the frequency response of the music.
OK, so now you’re convinced. Now, what kind of speakers to get? This depends largely on the program material. If you’re doing rap, house, fusion jazz, or any other format that requires lots of deep bass, you ought to consider a three-piece system that includes a matched subwoofer. These systems offer the best bass response for the money.
Entries from Mackie and Event into the nearfield monitor category offer good low bass at short ranges. They won’t fill up a large room with wall-shaking bass but they can put a reasonable amount of deep bass in your face up close. These systems offer built-in amplification, with amplifiers matched exactly to the speakers they are driving. Definitely worth a listen, especially if you also need a good amp.
What about the ubiquitous Yamaha NS-10s? These are industry standards. One of the best things to be said about them is that they are common to almost every studio. You can go into a studio with NS-10s and hear a familiar sound, and thus be pretty sure of what you are getting. NS-10s are good for doing mixes because they are very flat above 100 Hz. Below 100 Hz, which includes all the deep bass, they don’t offer squat. However they are predictable, and once you learn to mix on NS-10s you’ll get the same mixes every time. I know a few engineers that mix on NS-10s exclusively, and while their mixes are balanced, they seem to have less bass than they should. If you’re doing rock / punk then NS-10s are probably OK.
I will take a moment for a personal plug. Toby Guynne of Toby Speakers in Fort Worth Texas offers the definitive more-for-less speaker systems. His D-6x (D-60, D-61, etc) model speakers have the best response, imaging, and price point available of any speaker at even twice the price. Each is handmade, with handwound voice coils, custom Vifa tweeters, and lots of heavy-duty construction. Each speaker is guaranteed for life except for burnout (this includes all mechanical failures except pure overload) and each speaker has its own unique frequency response graph and is matched at the factory for optimum imaging. Toby is a lousy customer-service engineer and businessman, but he is one fantastic speaker artist. Personally I will use no other speaker.
While I’m plugging away, let me add that the place to go for acoustic treatments of all kinds is Markertek at www.markertek.com. These guys have it all, from soundproofing materials to Sonex to sound blankets. Check out their catalog.
So now you’ve got a decent sounding room with happy neighbors and a good system for playing back what you’ve recorded. Now let’s start burning some bits. Next month we’ll look into mixers, microphones, mic preamps, and converters.