Preparing FLASH presentations using voice-over-talent.

Is a high speed connection necessary for a web presentation using voice talent?

Although a having a high speed connection offers many advantages, an extremely effective presentation can be carried on 56k or 33.6K connection. If a presentation designed properly, even 28.8K connection can work effectively.

How do you get voice-over to work on low speed connections?

The trick is to space out the audio clips so that there is plenty of time for them to download. Of course, you can always use a "preload" segment before starting your presentation, but there are plenty of ways to avoid preloading, or to "mask" the preload so the viewer isn’t aware of it as "preloading" time.

How can you "mask" the preload?

One extremely effective method is to provide text for the viewer to read while the audio is downloading. If the text is fading in, or a "text crawl" is presented on screen, the viewer’s attention is on the text, giving you plenty of time to load the audio before playing.

What kind of audio compression should one use?

Currently MP3 files offer the best compromise between fidelity and bandwidth. It’s a good idea to test various file "streaming rates" to get familiar with file size and fidelity results.

I used Swish 2.0 to create the demonstration programs on www.web-vo.com. I found it best to import .wav files, and let Swish’s built-in mp3 encoder do the compressing. The streaming rates flash creates are determined by the original .wav file’s audio format.

I experimented with a 10-second .wav file, and here were the resulting .mp3 file sizes created by Swish 2.0:

Original Rate Stereo/Mono Original Size  Compressed "Swish" Size

44.1 kHz

Stereo

1.723 MB

70,267 kb

44.1 kHz

Mono

862 KB

40,159 kb

22 kHz

Stereo

862 KB

70,267 kb

22 kHz

Mono

431 KB

40,159 kb

16 kHz

Stereo

626 KB

40,367 kb

16 kHz

Mono

313 KB

25,235 kb

8 kHz

Stereo

313 KB

40,367 kb

8 kHz

Mono

157 KB

25,235 kb

Note that there was no difference in the final file sizes between 44.1 & 22kHz. Substantial differences resulted depending on whether the original file was mono or stereo.