Most novices to the video industry give priority to images. Nothing wrong with that – even poets and philosophers have traditionally given eyes more importance. Were they right? Think about this:
Firstly, audio can exist alone, and can be a pleasurable experience by itself. Video without audio is a pain to watch. If sitting through a few hundred family vacation photographs is tough, imagine watching 24 images per second of it!
Secondly, from the moment we are born to our last breath our ears are always hearing; which means for some reason our body thinks it’s super important to have ears that last a lifetime, working 24/7. On the contrary, eyes are shut for at least 30% of any average person’s life.
Thirdly, storytelling started with audio. Stories were passed on over thousands of generations via voice alone. We still do it today.
Finally, audio has a powerful ally, called music. One might like or dislike it, but few will deny its influence.
So, are we taking our ears for granted just because it’s always open?
Whatever the reason, one of the big lessons any filmmaker learns over the course of a career is the importance of audio. Some give it a 50:50 importance. I give it a 60:40 advantage over imagery, but that’s just my opinion.
Whatever you do, respect audio from the beginning. It is important. It is powerful. It can lift your video up a few notches.
I’ll go so far as to say: if you’re shooting your first movie or short, find the best audio workflow possible and allocate a budget for it. Spend whatever is left on your camera.
As we have seen in the last chapter, the cameras used in this guide have four broad kinds of audio connectors:
- 3.5mm jack
- RCA jack
- 1/4 inch TRS jack
- XLR inputs (various pins)
What are the advantages of XLR?
Just like HD-SDI has many superior features geared for rugged professional use, XLR is its equivalent in the audio world. Its advantages over every other type of connector are:
- Lock-in connector
- Ability to supply power
- 2 to 9-pin configurations, for various applications
Some cameras, like the BMCC, have two 1/4″ TRS jacks for professional balanced analog audio, switchable between mic and line levels.
What’s a balanced analog audio signal?
The 1/4″ TRS has two conductors, called the tip and the ring. The pyramid-shaped tip is the tip, and the space between the two black rings (insulators) is the ring. In an unbalanced system, the tip is the left channel and the ring is the right channel – which means each connector is capable of stereo sound.
However, on a balanced signal, the 1/4″ TRS connector only gives mono sound, which is why BMCC has two of them.
What are some advantages of the 1/4″ TRS?
TRS connectors are usually used in professional audio systems in the studio, so don’t let anyone tell you they don’t offer professional audio quality.
They save space on a console, and are easy to plug/unplug when you want to keep switching between connectors.
What are the disadvantages of 1/4″ TRS connectors?
From wikipedia: The socket grounds the plug tip and ring when inserting or pulling out the plug. This causes bursts of hum, cracks and pops and may stress some outputs as they will be short circuited briefly, or longer if the plug is left half in.
So it is critical that the connectors aren’t touched during operation – which brings us to the second disadvantage: There is no ‘lock’ as in XLR connectors. It’s easy for someone to step on the microphone cable and ruin a take. Lastly, TRS connectors cannot give phantom power (which means supply power to) to the microphone – so you’re going to have to depend on batteries.
1/4″ TRS connectors are smaller than XLR connectors, so it is clear why BMD decided to use them on the cramped BMCC side panel. Most prosumer and high-end cameras have XLR inputs, and the DSLRs have the least professional kind.
In fact, the kind of audio connectors a camera manufacturer provides on their camera is a clear indicator of what they think of their own cameras!
For headphones, almost universally one finds the 3.5mm jack. It is simple and reliable, and only needs to supply stereo audio. But don’t make the mistake of connecting it to external speakers, because that might not work.
It’s a question of power. To know more please read Driving Miss Digital.
Classifications of an Audio Production
I’m going to use a system of categorizing audio productions that I made up:
- Level One – Recording audio in camera
- Level Two – Routing audio through a device and feeding to camera
- Level Three – Recording audio separately with timecode and/or clapperboard sync
Level three is the only way to get the best audio quality – perfect for broadcast and feature film work. This setup gives as much creative freedom to a sound recordist as the camera does to a DP. If I had a choice, I’d always choose level three.
Let’s take a look at these levels in detail.