Sound Advice: Unconventional Audio

You read Videomaker every month and you’ve read this column before. You know the smart video producer always uses external microphones and the highest quality music and sound effects to create the best video possible. But what happens when the lines blur a bit? What if your next project calls for a telephone interview or audio from some ancient source such as a phonograph record? You remember them don’t you? Big black discs with a tiny hole in the middle and funny, circular grooves, right? Well, don’t worry: This month’s Sound Advice is all about recording from odd sources and how to get the best possible sound.

The Hardware

Before you jump into your first recording of that artesian yak horn, there are some basic tools required to record from odd sound sources. Your best friend is your camcorder. It is portable, it runs on batteries and, hopefully, it also has a microphone input. Internally, the input will have a preamp and, of course, the camcorder ultimately functions as a digital tape recorder. The fact that it also records video is merely incidental, for our purposes.

You’ll need a way to connect your external gear to the microphone jack. If you already use balanced microphones, you probably have everything you need. If not, a trip to Radio Shack is in order or check the ads in the back of this magazine. You’ll find unique audio adapters from Beachtek, Studio 1 and others that include microphone and line level inputs, volume controls and an attached cable to connect to your camera. Although these items are slightly more expensive than a bag of adapters, they are also more flexible and offer you greater creative control.

Another option is a small audio mixer. Behringer, Mackie, Yamaha and others offer compact mixers that allow you to blend multiple sound sources at different levels and connect them to the microphone input on your camera. Some even run on batteries. These mixers are better and more cost effective than ever before. Consider it an investment in the quality of your video productions.

Don’t forget your computer sound card. You’ll still need the right cables and adapters, but even the most basic model becomes a simple mixer interface.

Vinyl Visions

Squeezing sound from a turntable is one of the more challenging recording tasks. Not only must you find a working turntable, you’ll also need a phono preamp that compensates for the unique needs of those cranky old discs and devices. A phono preamp is a special device that amplifies the tiny signal from the phono cartridge and applies a special equalization curve that compensates for the changes made during the mastering process. Phono preamps are available as stand-alone devices and are often a part of stereo receivers and DJ mixers. In other words, you probably can’t just hook up your turntable to your camcorder.

Still, it isn’t that hard to use the output from your stereo receiver to go into your computer. Once you’ve got the signal chain established, connect the output to the line input on your sound card and hit the record button on your favorite audio recording program. Once you’ve recorded the track, some simple equalization tweaks will minimize the rumble from the turntable motor and brighten the sound. Many good audio editing programs (and even a few video editors, such as Vegas) even have scratch-and-pop removal filters to clean up those recordings, although the authenticity of the vinyl is sometimes a desirable sound element. Aren’t you glad you don’t have to do this every day?

London Calling

Recording from a telephone is another challenge altogether. The broadcast industry uses a special device called a telephone hybrid to put callers on the air. I’m guessing you don’t have one of those, so here are some more economical alternatives. From a landline (i.e. a standard home telephone), you can use a small, inexpensive device called a telephone recording control that attaches to your home phone line, extracts the audio and outputs that sound on a mini phone plug (1/8-inch). Again, this signal can go into the input on your computer or, with an adapter to lower the level of the signal; you can jack into the microphone input on your camcorder. Even less expensive is the suction-cup inductive pickup. This little jewel literally sticks to the earpiece of your telephone and plugs into a mike input. The quality is dependent on the telephone you’re using, but will work on home phones, office phones and even pay phones. If your telephone has a speaker phone option, you may be able to get away with no additional equipment whatsoever.

If you’re recording from a cell phone, your options are more limited. Short of a specialized (but usually inexpensive) adapter for your specific make and model of phone, the next best option is to simply point the directional end of a hand held microphone into the earpiece of the phone. This makes conversations a little difficult, but this technique actually yields a surprisingly nice result. Place the telephone in a nest of pillows on a bed, couch or upholstered chair to minimize external sounds.


Analog Answers

In addition to turntables and telephones, there is a multitude of analog sources to record. In fact, you might need to record from a cassette deck, a radio or even an aging analog camcorder. Virtually all these devices have one thing in common: they output audio at line level, not microphone level. This presents a bit of a challenge if your only recording option is a camcorder, which wants a microphone-level signal. Without a mixer or another device to reduce the signal to microphone level, your next best option is to record directly into the sound card of your computer. Once again, it’s time to dig in your bag of adapters for the magic combination, but a simple RCA to 1/8-inch stereo cable and a couple of dual-female adapters should do the trick. Play a sample of the audio and, using the software recording control in your operating system, adjust the input level so it never clips. Now you’re ready to record. One last reminder: DV video projects are best at a sampling rate of 48,000 Hz. If you have the option to start recording at this rate, it eliminates a (hopefully automatic and transparent) conversion step later.

Adapt or Die

Armed with your newfound knowledge and a handful of adapters and cables, you’re ready to face almost any audio recording challenge. If you keep your mike and line level devices straight, the only problem you’ll have is deciding what to do with all the time you saved and the money your clients will lavish on you.

Contributing Editor Hal Robertson is a 20-year audio and video production veteran and owns a media-production consulting firm.

[Sidebar: Sounds Like Fun!]

Sometimes, you have to build your sounds from scratch. For those times, here are five shortcuts to fun and creative sound-alikes.

  • Fake Phone: The audio is already recorded, but you need it to sound like it’s coming across a phone line. Using the high pass and low pass filter option in your editing software (or the equalizer), remove all frequencies below 300 hertz and those above 3,000 hertz. This closely emulates what happens to the sound over a real telephone connection. If the source audio is stereo, convert it to mono as well.
  • Police Calls: A simple pair of FRS (family radio service) radios (essentially modern walkie-talkies) will quickly simulate the sound of a two-way radio conversation. Just place a hand held microphone on the speaker of one radio and speak into the other. Sometimes the most obvious solution is the best solution.
  • Old Audio: To simulate the sound of a Victrola or old radio broadcast, place a Styrofoam cup over the end of a hand held microphone. This takes some improvisation, but when you get it right; the sound takes on a papery, scratchy quality. Again, make sure it is monophonic.
  • Witness Protection: Anonymous interviewees often need their voice altered to help mask their identity. Mixing in a pitch-shifted version with their original audio is a common technique. Shifting the pitch down a few semi-tones for women or up a few semitones for men. Sure, it sounds squirrelly, but that’s the point.
  • Sound Effects: There is an old story about Orson Wells recording the sound of a mayonnaise jar opening in the bowl of a toilet to produce the sound of a spaceship door opening for War Of The Worlds. Yes, that’s strange, but also quite creative. The point is that almost anything goes if you need a unique sound effect.

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