Recording Sound for Internet Distribution

You can't fix it in post-production

Sound is all there is

Wow, that's a big sweeping (honking) statement. Turn off the sound on most movies and see what you get out of it. Typically not much. The single most important element of most movies is sound. Most of the "information" passed to the audience is the result of dialogue. No matter how much you emphasize the visual element, even if you have Spielberg as your director, nothing changes. (Exceptions: Some movies intentionally use little to no dialogue.) So, this is where you grab your sound guy by the ear and say, "I know you know everything there is to know about sound, but Internet distribution is different," as witnessed by a host of movies that have nearly unintelligible dialogue when distributed over the Internet.

There is a reason why you can't fix sound in post-production... except at more expense than you pay the sound crew. When one voice is low, the difficulty is, the background noise is already mixed in, so you can't raise the gain on one voice without raising the other, which solves nothing.

Another problem is the acoustics of the environment is difficult to duplicate. Every room or aread reverberates differently. A good sound guy will record several minutes of background sound so if you need to dub lines later, you can dub the errant line over the background... but that doesn't create the reverberation of voices. To fix that problem requires dubbing all voices in the scene.

If you try to fix one actor's lines with dubbing, it doesn't work. The two voices sound like they are in two different places. So you have to bring both actors in and dub all of their lines for the entire scene. Well, sometimes you just can't get the actor's lines in a noisy environment and have to dub the entire scene anyway. But dubbing is expensive - why set yourself up for that expense if it isn't needed?

There is another reason why sound doesn't get fixed for Internet distribution in post-production. Most post-production work on sound emphasizes the theater experience. In a theater, the sound is played at a very high level, so people can usually pick out the dialogue from the background sound and music. Few movies on Internet distribution are shown in theaters. The majority are shown in homes or on mobile devices, on 20 to 30 watt speakers, or 3 watt speakers, or less, and the sound environment is very different. If people played the sound at theater levels, they would be arrested for disturbing the peace. But the quest in Internet video is becoming a drive for best sound. Streaming Media Extra article: Audio Catches Up: Online Video Rocks with Multichannel Audio.

The point here isn't to present some tutorial on sound - leave that to the sound guys who really already know this stuff. The point is, the things that you might have gotten away with in theater, don't perform that well in other environments. Sound for Internet distribution is more exacting. It has to have the versatility to perform well from devices with poor sound - mobile devices to home theater... and even theater. For more information on controlling sound, a BSS Audio equipment manual gives a good explanation: DPR-402 (Dual compressor, de-esser, limiter).

One simple technique is to boost the bass and suppress the treble, for small devices with small speakers. Another technique is to use surround sound techniques.

Journal of Sonic Studies article, EDITORIAL: Rethinking Theories of Television Sound

Surround Techniques

The strange human ear

Just a little explanation will help. Most 20 something sound guys will hear the sound they are monitoring very well. Well, it isn't that simple.

The human ear passes information to the brain at a wide range of volume levels. We don't really notice big changes in volume. It actually takes twice the power (3db change) for the human ear to even notice a difference. So we hear crickets chirping in the woods outside the window, a frog adding to the serenade, the clock ticking on the wall, and the child screaming in our ear. We hear these just fine and are able to differentiate between them. We may even know that the frog is not a cricket while the kid is screaming... but probably won't care.

One major difficulty is age and noise damage. The ear changes as people age. They lose the ability to hear higher frequencies, and voice frequencies. People in their sixties, or those who have listened to a lot of loud music, often lose the ability to differentiate a speaking voice from the background sound, which means they can't understand what people say if other sound is present, often even with a hearing aid. This makes the inherent problems of sound even worse. Over the next twenty years, each age in our population will be equally represented. There will be as many twenty-year olds as there are 80 year olds. People who can't understand what actors are saying simply won't watch - that's a large portion of the potential audience.

On TV, with all sound blaring from the speakers, the way it is edited for theaters, means that we hear all sound at around the same level, competing for our ear's attention, and we miss a lot of detail. For example, morning TV news programs often have music in the background as the hosts speak. You really can't decipher what the host is saying because the engineers have the music level too high and it drowns out the speaker.

Next page: Best practices for recording sound on set.

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