Well, I hope since the last article that you have settled on a microphone to use for your voiceover work and that you have placed it on your favorite mike stand. Now, after plugging the microphone into your mixer, and your mixer into your stereo compressor/limiter, and that gear in turn is patched into your Toaster/Flyer or the audio card of your VT2, you're ready to make some killer narrative voiceovers!
What's that? You say you've been experimenting and it still doesn't sound just right? What's the problem, Bucky�.. Do you live at the end of an airport runway in Atlanta? Is your studio located in downtown Manhattan? The neighbor lady's chihuahua yaps into the wee hours in your trailer park? The toilet keeps running in your "vocal booth"? Well, don't despair! All you have to do is some simple but effective acoustic treatment and you can minimize the noise eminating from the biker bar across the street.
First, let's identify your acoustic space that you have designated for voiceover work. Is it a large or small room? Do you have windows? Do you use nearfield monitors or a large pair of monitors? Is the gear in the same room as your microphone? All these factors fill in the equation which results in either a decent sounding and acoustically "dead" room or a reverberant nightmare of epic proportions. Let's try a few tests on your room and see (and hear) what's going on.
Stand next to a wall in the room and clap your hands. Do you hear "flutter"? (a slap back of the original clap) If so, then you have echoes caused by sound pinging back and forth from parallel walls. If your room is built in a garage or concrete-block basement, then you have problems. What you will need to do is to treat the walls with absorbent material of some kind. It comes is all sizes, shapes, and budget restraints. You can effectively use anything from the time-worn (and visually-impaired) egg carton treatment to the more recent professional diffusors and sound tiles available to the studio ower today. Also usable is carpet, foam, blankets, mattresses, curtains, sleeping bags, fiberglass insulation, and even styrofoam panels. Certain materials diffuse or absorb certain frequencies. Carpet and foam (or even carpet OVER foam) will absorb standing bass waves and help tighten up a room, acoustically speaking. Styrofoam panels will absorb upper mid frequencies and even some extreme highs. A healthy and amply supply of packing blankets are great for isolating sound and absorbing ambient noises.
As a general rule, porous materials (such as old, lumpy mattresses or overlapped blankets) absorb high frequencies best. You can use the simple approach and just nail the material to a wall. If you are cosmetically conscious then build baffles or place them in frames. If you use foam, remember that 4-inch foam placed on a wall absorbs frequencies from 400 Hz and up (mid-range frequencies). If you design spaces between your panels or treatment you are helping to diffuse the sound in the room. Another good trick is to arrange pillows, sleeping bags, or carpeting and cover it all with burlap or muslin. If possible, space the entire treatment several inches from the wall. This will add a bass-trap which will decrease the lower-mid and mid-bass frequencies. I have even reduced the high-frequency slap and tightened up the room by hanging an army surplus parachute from the ceiling.
Most of us suffer from low frequency noises from the outside world seeping in through the walls and windows, especially if you are located near traffic. There's nothing quite like the sound of a semi-truck passing by right smack in the middle of the quietest part of your narration. Or at the very least, you suffer from that constant 60 Hz hum produced by that nearby air conditioning unit you have blowing away in a futile attempt to keep your hard drives cool. Absorbing low frequencies is a tough assignment. You could start by making some bass traps. Take several 35-55 gallon rubber trash cans, drill them full of holes, fill with fiberglass insulation, and place one in each corner of your room. Or build a 3-foot-wide lattice frame of wood slats the same height as your ceiling.Cover it with muslin or burlap. Place the frame diagonally across a room corner and fill with R-30 insulation. Leave the foil on, foil side out toward the room. Place one in each corner.
It also helps to open closet doors, move couches and padded chairs slightly away from the walls, and place anything in such a way as to reflect any sound from a parallel wall. Room resonances are worse in a cubical room. They are less of a problem if the length, width, and height of the room are different. To tighten up your mixing/listening environment, place foam on the wall between your monitor speakers.
Now, to hit the "hot spots" remember:
Foam improves your speakers imaging and frequency response.
Tubular bass traps in corners reduce standing waves and absorb low frequencies.
Wedge-shaped foam diffusors reduces reverb and flutter echoes.
Unequal dimensions reduce standing waves.
Insulation-filled lattice will decrease bass leakage.
Or if you have the budget and/or desire a room which has a more professional appearance, you may want to invest in the purchase of professional designed (and obviously more expenses) acoustic treatments from companies like these:
www.auralex.com
www.tubetrap.com
www.acousticalsolutions.com
http://www.rpginc.com
What else can you do to reduce room noise while recording? Here are a few pointers:
Turn off appliances and telephones while recording.
Unplug the fridge for an hour or two (be sure to re-plug it).
Pause for ambulances, semi's and airplanes to pass.
Make sure the AC doesn't come on during recording.
Close windows and cover them with blankets or a mattress.
Close doors and seal with towels or weatherstripping.
Replace hollow doors with solid ones.
Turn off all the fluorescent lights.
Turn off or get far away from any attic power venters.
Only turn on the recording equipment you are using.
In Part 3 we'll get into common techniques in voice-over recording.
Bob Ketchum, the Anarch of Acoustics, has left the computer to wage war with AC compressors, cooling fans, and that annoying drip in the bathroom sink
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