This could also be another report of ‘the bleeding obvious’ but I thought this was worth sharing.
You’re a videographer. You go out and shoot things. Ideally, you’d have your trusty Sound Guy beside you, but most of the time you’re on your lonesome. You’ve got good mics, you plug them into your camera. You get good level and you’re up on mic placement. An input’s an input, right?
We know that microphones generate very small signals compared to mixers and other devices chucking out ‘line’ level. To hear what microphones hear, we need to amplify them to the same line level before they get processed as ‘audio’ for the camera and bundled into the recorded video – whether that be on tape, as a file or whatever. The bit that amplifies the microphone input is known as a Mic-Pre – a Microphone Pre-amplifier, and it’s not exactly talked about on pro cameras.
It’s not normally an issue because your trusty Sound Guy takes the microphones, places them expertly, gets their signals into the mixer, balances them all and feeds the result to you as a Line level audio signal. All 16 bits of data per sample, at a perfectly adequate 48 KHz, get written with your data and it sounds great.
So Mr Videographer goes out and plugs his mics straight into the camera and, well, it’s good level. It sounds okay. It sounds fine. It will do. But if you’ve ever had sound from a good Sound Guy, you’ll know it has depth and sparkle and range and all sorts of things. My audio never had that. It was dull – competent, but dull. The 1.3 litre saloon car compared to the 2.0 litre Ghia version I got with my Sound Guys.
Oh, they had better mics! No, I bought the same they used, and they used mine. ECM-77, Sennheiser 416, Sanken COS-11, Sanken CS-1 – it’s a role call of industry standard mics.
I moved to DSLR and dual system sound, started using a Zoom H4n for my audio, and tried upping the sample rate from 48 KHz to 96 KHz. I’d like to tell you that I did hear a difference, but have been told in no uncertain terms that it was a placebo effect. I thought 96KHz samples sounded more airy and full of the audio equivalents of ‘Volatile Organic Compounds’ or whatever gets emitted when you peel an orange or use some truffle oil – whatever the audio equivalent was, I could hear it but couldn’t convince my peer group that it was there.
So I tried using 24 bit over 16 bit. Now, there I darn well COULD get a difference, but it was dynamic range and that’s boring. if you let your camera meters wiggle up to the two thirds mark on your camera meters (I can hear a bunch of Sound Guys sucking their teeth as I type), any sudden increase in volume (speaker suddenly decides to ‘project’, car goes past) pushes everything into the red zone, audio crunches against the end-stops and it’s game over.
You have to set your ‘wiggle’ at that point, because if you go lower, you have to raise levels in post and suddenly you’ve got a nasty hiss that stains your audio recording.
At 24 bit, you can be waggling up to the half way mark with plenty of room to catch the loud bits, and the hiss is way back down there to the left, unnoticed by your edit software.
All that’s great. Go ahead, fill your boots – audio at 48KHz and at 24 bits for the extra and truly valued dynamic range. But I still didn’t hear what I wanted to hear and knew what these microphones were capable of.
So, cue the Pix 220 by Sound Devices – purveyors of some extremely good audio kit. Check the test out, make your mind up BEFORE the movie finishes.