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Creating Great Audio for the Web

by Steve McCannell
08/11/2000

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There are a number of reasons you may want to use multimedia with your business, whether it be for company-wide updates or to publicize a piece of music. Whatever the reason, you will need to know certain techniques and methods to get your media to your audience.

This article will take you through the steps and techniques used in the recording process, showing you how to polish your recording using the many audio manipulation software programs available, how to choose which format to present your material, and how to serve it to your users.

Recording 101

There are three things that you will need to record audio to your computer: a microphone, a reasonably fast computer with an input-enabled sound card, and an input source. Well, four actually; you have to know how to get your recordings to your computer. Take a look at the back of your computer casing and find where your speakers are plugged into. This is your sound card. You will see other empty jacks on the same card. You will need to plug your source into either the line-in jack or the mic (microphone) jack. Now open whichever audio recording software program you use (if you don't have a specialty program for recording, both Windows and Mac come with recording programs with their operating system.) Generate some signal to your sound card and press the record button. Easy, wasn't it? If you are having trouble hearing your recordings upon playback, chances are you have the wrong input source selected and just need to switch from microphone to line-in or vice versa.

One of my favorite quotes is "you can't polish a turd." Apply this to your recordings; you can only get out what you put in. So here are some basic things you need to think about before you hit the record button.

  • Buy the highest quality microphone within your budget - When you are shopping for microphones, the more expensive they are, the better. This being said, there are some microphones that cost thousands of dollars. Unless you own a professional recording studio, you won't need to waste your money here. You also won't want to use the Radio Shack variety of microphones. An even compromise would be to get a multi-purpose microphone for around $100, such as a Shure SM57.
  • Everything is quiet - Make sure that there is no background noise and that the air conditioning is turned off. You may not be able to hear the air when it hits your ear, but I can guarantee your microphone will. If you can afford it, buying a shockmount for your microphone will reduce any vibrations that may get induced into the mic from the floor (loud trucks driving by, low frequency sound waves coming from a speaker).
  • Avoid bass boost - If you are not using an omni-directional microphone, you have to be careful of proximity effect. This occurs when the microphone is placed too close to the source, causing a bass build up that can be difficult to smooth out in post-production.
  • Set good levels
  • - One of the common mistakes of digital recording is a bad signal-to-noise ratio. Make sure that you are getting the highest level into your recording equipment without distorting the signal.
Input levels set too low Input levels set too high Input levels set correctly

Input level set too low

Input level set too high

Input level set correctly

Audio for video

Let's say your CEO is going to give a "state of the company" speech, which will be videotaped and distributed to the various arms of the company, and you are in charge of the recording. Seeing as the words being spoken are just as important as the video that accompanies it, you will probably want to think about how you will record the audio. The microphones that come with most consumer-grade video cameras are not up to the task; they tend to introduce noise from the camera motor, and speech is usually muffled. The best alternative for recording audio for video is to use an external microphone.

On your camera, you should have a mic-in port. By using this, you bypass the camera's internal microphone, and the input will come from your external mic. Choose a microphone that is up to the task at hand. If you are recording spoken word, you should almost always use either a handheld or a lavalier cardioid microphone.

Hear the difference

From the same vantage point, we recorded spoken word using three different microphones. Take a listen to hear the difference with each one.

 •Internal microphone from camera
Real Player  MP3

 •External omni-directional
Real Player  MP3

 •External lavalier microphone
Real Player  MP3

To prove this point, we recorded using three different microphones with a consumer-grade digital video camera. The first microphone we used was the internal microphone on the camera. Not only do you pick up the room ambience, but you also pick up camera noise and any noise that the videographer may make, such as a nose sniffle or cough. You also have to worry about your distance from the source. If you are too far away from your speaker, your audio will sound very distant (and zooming in won't help). If you're looking to focus on one or two subjects, I wouldn't recommend using this method.

Next we used an omni-directional microphone placed near the speaker. An omni-directional picks up sounds from every direction, so you'll notice that the room acoustics are easily picked up with this method, as well as footsteps and creaky floors. This method would be great in the middle of a discussion, but maybe doesn't quite work when there is only one subject speaking.

Finally we used a lavalier microphone with a cardioid polar pattern, attached at the speaker's collar. Cardioid microphones pick up sounds that are directly in front of the microphone's diaphragm, while sound waves coming from the side or behind are picked up at a significantly lower level. You'll notice when you listen to the recording that you do not pick up a lot of sound reflections from the surroundings, the speaker's voice sounds clear, and there is little to no background noise. This is due to the fact that the speaker's body blocks the reflections coming off the wall behind the speaker, and the microphone is closer to the input source, making the recording truer to the speaker's actual voice.

Typical polar pattern of an omni-directional microphone

Typical polar pattern of a cardiod microphone

Graphics courtesy of Audio-Technica

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