One of the most common questions posed by beginning and intermediate recordists is "How do I get rid of background noise in my recording?" It's all too easy for 60-cycle hum, air conditioner drone, mic cable crackle, traffic noise, and many other ugly artifacts of modern life to sneak into our pure audio signals.
Your first impulse might be to bash at the problem with technology: almost every digital recording program, from the high-end Pro Tools to the free (yet robust) Audacity, has some method for reducing noise. (I use and swear by Sony Sound Forge.) O'Reilly covered several high-tech approaches in the article "Seven Steps to Noise-Free Digital Audio."
But my answer to the "How do I get rid of noise" question is different: "Don't have any background noise in your recording."
That sounds snippy, but it isn't really. It's a lot easier to do a little planning and have no noticeable noise in your signal than it is to get rid of noise later. I never use any "fix it in the mix" audio filtering. I don't like noise-reduced audio; it all kinda sounds like robots whispering in the background to me. Noise-fixed audio will never sound as good as audio that had no noise to begin with.
That said, having no noticeable noise in a recording wasn't always possible. Analog tape, tube amplifiers, mixers, and vinyl all added noise. Beatles and Led Zeppelin records, often cited (and rightly so) as pinnacles of analog recording, all have some noise that anyone with decent ears can hear on headphones.
Today, the average kid with an off-the-shelf laptop, a relatively inexpensive mic, and a USB audio interface has the potential for a sonic purity that George Martin and Jimmy Page never had back in the day. But how come Zeppelin discs and the Beatles still sound way better than what the kid with the laptop does? Well, partly because it was Zeppelin and the Beatles being recorded, and partly because George Martin and Jimmy Page were at the controls. And partly because they were using amazing "don't make 'em like they used to" Neumann microphones, and recording in some of the most sonically perfect rooms in the world.
The O'Reilly Digital Media site is generally aimed at mid-level users, but I think it's germane to show the top of the curve as well. I'm mainly going to cover recording with $100–$250 microphones in this two-part article. But the techniques apply even if you're using cheaper mics, or much more expensive ones.
As for the top of the curve: My friend Dave Bock engineered "To Elvis in Hell" (free download here), the first record by my band Bomb in 1986. Dave has gone on to perfect microphones that work much like the original Neumanns and AKGs.
Dave's mics are pricey — $1,000–7,000 — but many high-end engineers and producers swear that Bock microphones sound as good as the old German tube mics, which range from $5,000–$20,000, if you can even find someone willing to part with one. It's hard to find a good-condition antique Neumann or AKG for sale; they're like classic cars. People who can afford them have bought up the few that exist and won't let them go.
Here's a podcast (60MB MP3) of me interviewing Dave Bock through his mics, as syndicated by GearSlutz.com, the high-end audio forum. The recording sounds amazing and creamy, even though I was running into a cheap mixer, with a cheap preamp, in a room with a lot of reflective surfaces, not a recording studio.
So, there's the top of the curve. As for the bottom, I've used a Sennheiser E822S. It was on sale for $30 from MusiciansFriend.com, but I didn't buy it. They sent it free when I ordered something else. I gave it to my cat to bat around for a while; then took it into a locked room and did awful, horrible things with the mic, which I can't go into here; and then threw it away.
Neumann used to make the best mics in the world, but then the kids of the owner sold the company to Sennheiser. Sennheiser now makes mics called "Neumann," and they look like the originals, but don't let that fool you. As one guy on GearSlutz.com forum has in his sig line, "The Neumann family should have left the shovel in the garage."
If you must cheap out, spend 69 bucks for an MXL V63. They sound a lot better than the Sennheiser.
I'm not George Martin, but I can record some pretty damn great-sounding audio using a standard laptop, a $150 mixer/USB interface, a $225 microphone, some free software, and little else. The rest is just talent and tricks, and I'll turn you on to the tricks. What I'm talking about here is not the software, and it's not the computer. It's mostly about what happens before your signal even hits the computer.
Basically, to get a really good recorded sound, you need to place a good microphone close to the sound source in a quiet room with sound-absorptive walls; feed your microphone's signal into a decent preamp; level the sound so it's not too loud and not too quiet; and send that signal to your computer via USB, FireWire, or another digital connection.
That sounds fairly simple, and it almost is. So why are we hearing so much horribly recorded audio these days?
Well, partly because the Internet is bringing this audio to us. There used to be a lot of poorly recorded audio in far-off places that would never get to my ears. But thanks to the Internet, I get to hear a lot of noisy, weak audio recorded in every state and every country — without even leaving the house. Also, cheap computer desktop recording gear is making many more people think they can be engineers, or at least try, and they'll proudly share their results with you, even if they're nothing to be proud of.
Don't get me wrong; I listen to (and love) lot of independent music, and some of that music is even made in someone's bedroom. But no matter how good the singing, songwriting, and playing is (and all of that, especially the songwriting, has to be pretty good for me to want to listen more than once), the music has to be recorded well for me to dig it. And if I have to fight past audio artifacts to hear what's going on, chances are I'm not going to listen to more than a few seconds.
Similarly, I love podcasts. I love the idea of citizen media. I love the idea that strangers can record their own radio-type shows in their homes and I can listen to them. There's something amazingly immediate and magical about the one-to-one communication of one person talking to another, even if it's done over the Internet. I love consuming podcasts and I love making them. I love the thought that my wife Debra Jean Dean, my friends, and I can talk in my home; I can quickly edit the conversation and upload it; and within a few hours, over a thousand subscribers have automatically downloaded it and listened to our thoughts.
I've checked out hundreds, if not thousands, of podcasts. There are four things I look for, and I have to be satisfied by any three to subscribe:
I can't help you with the first three. The first one is subjective. The second one is all about how your brain (and probably my brain) works. The third one is an act of birth.
But the fourth one can be improved.
The most common audio problem with podcast audio and home-recorded music is background noise. The second most common audio problem is hum or buzz. Another common problem is signal level — it's either too high or too low. If you eliminate these problems from your signal, be it spoken audio or music, you really are recording digital audio that's better than most.
Probably the most common background noise is simply the sound of the computer fan leaking into the microphone. You'd be surprised how common this is. I'd say 20 percent of all podcasts have this. If you're using a sensitive condenser mic and it's only a foot or two away from the fan, it can be pretty damn loud.
The basic solution for this is to get your microphone at least six feet away from the computer. Use a directional mic and point the sweet spot (the side of the microphone that picks up the most sound, usually indicated by a dot on the mic body) away from the computer. With a USB mic, you can often use a USB extension cord.
Tip: Some people have a dedicated computer just for recording. If you can afford it, do so. Don't connect it to the Internet, don't put a bunch of programs on it, etc.
A better solution is to get a computer without a fan. Some ultrasmall laptops like the Dell Latitude X1 don't have fans, but they're often twice the cost of a normal-size laptop and hampered by miniature keyboards that are hard to type on. My solution was to buy a second, dedicated recording computer — a desktop, not a laptop. You can get a decent one these days for under 500 bucks (300 bucks if you buy it used).
Add another 200 clams for a smallish flat-screen monitor. Cathode ray tube (CRT) monitors produce noise, radio interference, and can resonate mechanically at certain notes — yell into the cooling ducts on a the back of a CRT and it will quietly but resolutely sing back to you, an echo that sensitive mics will pick up.
You can take this dedicated tower computer, stick it in your closet, and run the cables to the monitor, mouse, keyboard, and mixer out through a little hole in the closet door. Then stuff that hole with cloth to keep out noise. You can even line the closet with rug scraps nailed to the floor, ceiling and walls. Do all this and the noise of the fan and hard drive (sensitive mics can pick those up too, even on a fanless computer) are safely ensconced in the closet, out of reach of your mics. Be sure the closet is big enough that the computer doesn't overheat, of course.
Tower computers are so cheap now. I just bought the fastest computer I've ever owned — for $425. I'm currently using it for nothing but uploading my media via BitTorrent. Interestingly I had to pay 25 bucks more to get it with Windows XP instead of the newer, more expensive Vista. (I hate Vista. It uses a lot of system resources to make the look fancy, which messes with recording power while not adding anything useful. Vista also does not work with a lot of my older programs that I like using and don't feel like upgrading.)
If you don't have a closet in which to isolate a tower or if you have only a laptop, just put your laptop as far as possible from your mic. And if you're using a laptop, I recommend placing a folded shirt or other padding under the computer so the fan and hard drive noises aren't amplified by your desk acting as a resonator. (Again, use common sense — make sure not to cover the fan hole, or you'll burn up your computer. You might even insert a small cutting board or other thermal barrier between the computer and the padding.)
If you can't afford a second computer, close all unnecessary programs (e-mail, virus scanners, Web browsers, etc.) before recording. They will, at best, use up memory you need to record, and, at worst, crash your recording mid-take.
For the optimum positioning and computer-noise avoidance, you can also record with a standalone digital recorder like the Zoom H2. I love this little thing, and record a lot of podcasts on it. It costs only 200 bucks.
The H2 is the size (and much the look) of an electric razor, and can record CD-quality sound (16-bit, 44.1kHz WAV), though you'll want to get a bigger flash memory card if you're going to record a lot. I call the H2 the "studio on a stick," and that's pretty accurate. (It comes with two different stands, a stick-like handle and a tripod-like table stand.)
You can record with the H2 using its surprisingly good onboard mics, or you can plug in a mixer, keyboard line output, or external mic. (Most mics will require an adapter; some may need phantom power as well.) You can then transfer your files to a computer via USB for editing. The H2 shows up as an additional hard drive — no proprietary software required, though you'll get much faster transfers with a card reader than the H2's built-in USB port. Here are the settings I use on the H2.
Incidentally, I haven't seen this mentioned anywhere, but it's been my experience that the H2 can pick up noises produced by cell phones and mar your recording. This can happen even if the phone is in an adjacent room and set to vibration mode. I recommend turning any cell phones off while using the H2.
This is kind of a no-brainer, but turn off your air conditioner and any fans in the room before arming for record. Even if it's 108° outside (as it is here in Southern California in August), turn your AC off just long enough to get a good take, and turn it back on when you're done. Sometimes if it's not too hot outside, but hot in the studio with the door closed, I'll run the AC for a half-hour to supercool the house before we record. It then it stays comfy while we're yacking out our podcast, even if it's a little cold when we start.
Refrigerators give off a lot of noise too. Don't record near them. Our old one was pretty loud and our condenser mics so sensitive that we actually used to have to unplug our fridge before recording. (Don't forget to turn it back on when you're done!) It was a very minimal sound, and most people didn't notice it, but my ears are sensitive enough to hear our old fridge in headphones 20 feet away through a closed door if we didn't turn it off.
We finally sprung 700 bucks at Sears for a new fridge. It's not only virtually silent, but we figured out that the savings in power will pay for the new one in 18 months. (Math here.)
Speaking of cool things, I'll share my personal gear recommendations in the second half of this story — microphones, mixers, power conditioners, compressors, and other recording equipment that's worked well for me. I'll also explain how you can soundproof your home studio inexpensively and effectively. If you have tips or questions on digital home recording in the meantime, please share them in our audio forum. See you soon.
Read more digital home recording tips in Part 2.