Q&A: Audio Queries

During the Post|Production World conference that ran alongside NAB 2008, I gave an extended session on audio connections, microphones, and other related issues. At the end, the attendees hit me with their individual problems. I thought the questions and their answers might be useful to others, so I decided to add them to the archives up here, amended with additional thoughts and research I’ve gathered since returning from NAB.

Note that essential companion reading to these comments include my previous article on audio wiring and connections, plus my blog on dealing with ground loop hum.

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Straight Advice on Loop-Based Music

For many years now, artists have been creating music using loops - musical phrases that can be repeated or strung together as building blocks of a song. This technique opened music creation to a large number of artists who may not be musicians themselves, but who had strong musical ideas: they could arrange these blocks into new compositions of their own without having to play all the instruments. We’re not talking just hip-hop or dance music, or phrases “sampled” from other songs; this movement is supported by literally hundreds of fully-legal copyright-clean dedicated loop libraries available from musicians and producers in every genre you can imagine.

Mangling Music Masterfully

If you are fortunate enough to have music custom-composed for all of your visual work, this article is not for you. However, if you are regularly handed music you have to make work underneath your visuals, and that music is not exactly the length you need, read on. We’ll discuss how to find the best places to slice it, whether you are trying to reduce its length or need to repeat a section to make it longer. We’ll then show how to cover your edit points and introduce variations. This will help you create your own custom version of the track, better suited to your needs. Click here to download source and project files you can use to follow along.

Timing Video to Audio

In the days of yore, editing video and audio used to be considered two different disciplines. Today, most desktop and non-linear video editing programs also edit audio with the same tools and capabilities. As a result, video editors are all but expected to also edit their own audio.

For most, this means just mixing together narration, music, and the occasional sound effect. However, if go one step further and make your video edit decisions based on the audio - and vice versa - you will end up with a final program that is tighter, and more compelling to watch, than if you just let the respective cuts fall where they may. The same goes for 2D and 3D animation: Allowing audio to inform your timing decisions results in a stronger overall experience.

Don’t know anything about audio or music? Hang on and we’ll give you a crash course in the next two pages. Already have a good idea of how audio and music work? Jump ahead to the section titled Cut Time on Page 3 and we’ll go over a few tips and tricks to keep in mind, followed by a brief case study. As with any artistic discipline, rules are meant to be stretched and broken - but they give you an important head start.

The Magic Tempos

Vibrations in a sound’s wave happen at a much faster pace than frames happen in video or film. Likewise, a musician may pick a tempo where the peaks of these vibrations - the beats in the music - don’t land on nice, even frame boundaries. However, there is a way to determine tempos that exactly line up with frames. If you can get your composer to use them, your job spotting the audio will be much easier later; you can even animate at these paces without hearing the music, knowing it will line up later.

I Can’t Hear You: Correct Audio Connections

I felt compelled to write on this subject because of a real-life experience that happened years ago. Trish and I were scheduled to show tapes and speak about our work at an event. We had both BetaSP and VHS tapes, as well as some QuickTime movies to show from a Mac. As is our custom, we asked to inspect the gear before we were scheduled to go on, just to make sure everything would go smoothly.

I started at the BetaSP deck. There was nothing connected to its normal audio output connectors - a problem, since we really focus on the interplay between audio and visuals in our work. However, there was something plugged into the “monitor” output on the back of deck. This is an extra RCA-style output jack meant to be connected to the corresponding input on some video monitors (to hear your work through that great two-inch speaker so generously built in). They were using this, but not with a phono plug inserted - instead, they managed to jam into a Walkman-style headphone plug into it, which then went to a pair of RCA connectors. An inauspicious start.

On The Level

Admit it: How many of you mix audio by dragging the music, narration, and sound effects or ambiance bed into your authoring program…and think you’re finished? Okay, you don’t, but I’ve heard numberous television programs and pieces of interactive media that sound that way. Each component might sound fine individually, but when more than one is playing at the same time, they obscure each other. Or maybe during quieter sections, an unacceptable amount of noise or distortion appears when played back on a system with lower bit-depth or compressed audio. The solution to both comes from proper management of audio levels.

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