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PART I1I SHARING YOUR WORK
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AUDIO
There are two categories of audio information: That which is sought out by the human brain (signal) and that which the brain purposefully does not attend to (noise).
recording sound
Audio was the first of the time-based media. Along with the earliest words, there surely came the rhythms our ancestors drummed and chanted. Human ears and eyes want to work together, and personal media has most impact when pictures and images are delivered in concert.
A microphone converts the energy of sound waves into the energy of electricity, which is then measured and recorded as digital information.
human voice
and sound effects
The human voice includes words, singing, and utterances such as screams and hums of delight.
Slide-making applications have protocols for attaching digitized music and effects tracks, called cues.
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CHAPTER 5: SLIDE SHOWS
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Either a scripted or an improvised voice track often accom- panies slide shows. Voice comes in three flavors: narration, which is often objective and detached; first person, which features the word I and personal commentary; and dramatic readings, which can include dialogue among actors or a monologue by one person. Try them all.
PowerPoint, iMovie, and other slide show engines all include ways to import digital audio files that will play along.
This screen capture shows what a chunk of audio looks like in the free sound-editing application Audacity. You can see two stereo tracks and the range of frequencies in each.
Let’s not forget music. This photo is a reminder that
a singer, in this case Erin Donohue, has a range of expression that can become the main attraction in a slide show. Behind Erin is Brian Littlewood, who is the DJ. The live mixing of recorded tracks is a bona-fide performance form in its own right, and you might want to incorporate it into a slide show, too. Jeff Ertz
Such cues can be looped, which means they repeat themselves automatically. This is useful if you are conduct- ing a click-through presentation. A very specific cue—for example a burst of wild applause—can be synchronized to accompany a particular slide. Finally, the rhythm of a musi- cal selection can provide specific beat points where slides are automatically advanced.
Very inexpensive microphones are available that you can just plug into the USB port on your computer to record au- dio. You can buy a microphone attachment for your iPod and start recording sound with little or no setup. It’s not easy to record high-quality audio, but if you take reasonable care in positioning a microphone close to the source you are record- ing, and if you try to record in a space with little ambient noise, it’s possible for almost anyone to get a clear record- ing of voice or music with even the most inexpensive device.
Blue Mic’s Snowball (left) has a cool retro look and costs around $160. The Samson condenser micro- phone (middle) is around $75, and the Logitech’s USB model (right) costs under $25. Keep in mind you always have to keep the microphone steady. Never tap it with your fingers to see if it’s picking up sound; that could damage the microphone. Snap your fingers instead.
importing music
Many slide show applications come with small libraries of sound effects and generic musical tracks. Problem is, they sound generic. Just as there are plenty of clip-art libraries on the Internet, there are also libraries of stock music and sound effects—some free and some you have to pay for.