The DSLR film revolution continues to boom. It doesn’t take long on a walk around London before you bump in to another mini film crew utilizing the new found technologies available to them, namely the cannon 5d mkii among others. These combo photo and film cameras have managed to convince photographers that they are now producers, able to do everything from script-writing to post production. This is all well and good in an age where speed is essential and budgets are low, but it is very easy for those of us educated in one field to not fully appreciate the technical attributes of others.
My biggest grievance is that born and bred photographers often fail to recognize that sound is a very similar beast to photography; as photography works in the limitations of thevisual light spectrum, sound operates with in the audiblefrequency range. We shouldn’t regard one as more important than the other. I have heard it said many times that “a good audio track makes or breaks a film”. This is usually the sentiment of filmmakers or soundmen, not photographers starting to branch out to film, but I can’t stress it enough
Technology moves at a phenomenal rate now and it would be counter productive to review every bit of kit that comes out just for the sake of it. However, now and then something comes along (like the 5d mkii) that not only offers people what they need, but also opens up a whole new learning experience.
The zoom H4n is categorised as a field audio recorder but is capable of much much more–in fact, way too much for the purpose of this article. It’s got built in XY axes microphones adjustable from 90 degrees to 120. It’s capable of the basic effects used by most sound engineers during mixing such as limiters, compressors and lo cut filters. It can be used as an audio digital transformer interface (ADT) with your computer, meaning you could used it as a pre-amp direct into your sound editing software. It has a tuner and a metronome built in with all sorts of guitar effects like reverb distortions, phaser and flangers, a multi track recording mode and two XLR / jack inputs with phantom power.
But let’s get back to the point. If you’re a photographer most of that means nothing and your idea of recording an audio track consists of pressing the big red button on the front and just accepting that that’s it. Fortunately this approach with the H4n can actually produce stunningly good results. Lets go back to school for a minute and look at a couple of the fundamental basics of sound. Don’t worry, you will still only need to press the big red button at the end of this and get away with it. But just think what you could produce if you looked at your sound with as much criticism as you would give a final edit for an exhibition.
One big problem with recording a good stereo image is the necessity to record with two tracks, so two microphones are needed. You can equate it to the difference between a telescope and a pair of binoculars. Through the telescope you only have the one point of reference to the position of let’s say, a tree in a field, and therefore are not able to judge its position any more than the fact that you know roughly how big a tree is. Through the binoculars your eyes are able to look at the tree from two perspectives. This is called triangulation and it is what gives us the ability to judge distance.
The exact same principle applies to our ears.
There is another thing we have to add to the equation when recording sound. It’s called phase. You can be in phase (good) or out of phase (not good).
In phase means that the audio waveform of your two stereo tracks goes up and down at the same time. In an out of phase recording the waveforms are offset, so as one goes down the other goes up. This effectively causes the two waveforms to cancel each other out slightly and you end up with a kind of flat, dampening down of the track.
So you are about to shoot an interview with your stereo recorder in the same position as the camera, the interviewee stands center frame there for the sound has exactly the same distance to travel to your two microphones. But let’s say that there are other interesting things happening in the shot. For example a man is busking to the left-hand side of the shot. Because of his position the sound wave reaches ( on recorder where the microphone placement is side-by-side) the left hand microphone first and then the right hand microphone. This slight delay between the two microphones is called the lag time, and it is because of this that we get out of phase recordings. In the case of the zoom H4n the microphones are arranged in what is referred to as an XY axes, this means that the two microphones are placed one on top of the other at 90° to each other. Because of this arrangement the sound wave reaches both microphones at the same time. This eradicates the lag time and produces a stereo image that is in phase.
The XY axis set up is by no means unique to the H4n. It is a standard practice throughout the recording industry, and is as near to the front pages on how to record sound as correct exposure is to photography. I regard the H4n in the same way as my first SLR, a new and exciting tool in which to learn and progress to a higher standard.
In a time where multimedia is the buzzword, we as independents cannot afford to be ignorant of such basic technologies and practices. It is the understanding and application of these principles that will allow us to shine out in this incredibly competitive industry.
Andy Ash - www.andyash.com