I worked, far in the past, as a creative director for an advertising agency. When we did commercials back then we used 35mm film and all audio was recorded separately and matched to the visual footage in post production. It was the same about a decade later when I bought a Rolex 16mm camera for personal work. There were crystal sync modules that applied a pilot signal to the audio and film to keep them on the same time lock but stuff like PluralEyes (an automatic audio-to-video matching app) didn't exist. Or, if they did most of us shooting movie film didn't know about them...
When we started working with video in conjunction with DSLR and mirrorless cameras one of the nice things was the ability to record audio right into the camera and have it locked in step to the video. Very nice. Except that early cameras were primitive and aimed at a non-professional market. The audio inputs were not balanced, not set up to work with professional microphones and, worst of all, the early cameras had built-in automatic audio level controls. They just weren't suited to pro work. To compound the problems, up until recently, the pre-amplifiers for microphones that were built into the cameras were kinda crappy. They were noisy and given to fits of unexplained audio rage.
Eventually many of the early issues were sorted out but one issue dogs many of the cameras that are currently on the market; they have little 3.5mm TRS microphone jacks and they are set up for non-balanced inputs from consumer microphones that have a different output impedance than professional microphones. Trying to use pro microphones with little adapter cables gets the signal to the camera but it's usually a woefully bad signal that's plagued with noise and all kinds of aural issues.
I think we've all pretty much come to the conclusion that clean, nice, happy audio is at least as important to the creation of pleasant and watchable video programming as is a decent visual file so this mismatch is a clutch point for many.
A few years back I bought a decent (but not great) shotgun microphone that had its own internal amplification and it was powered by an internal battery. It was supposed to sound okay but it was a disaster if I plugged it into my digital camera by way of a plug adapter. It required a bunch of gain from the camera's pre-amplifiers and the sound was just... off. That's when I decided to do some research and understand what I was missing. It was all about the impedance mismatch. My camera was expecting to see something at one value but my microphone was hellbent on delivering a signal designed for a different, more professional input. Electrically speaking they were never going to be in a happy relationship without some sort of buffer in between them. Also, the balanced, three connector XLR connections, delivered in conjunction with shielded cables were important for reducing noise and intermittent glitches. What was needed was --- translation.
What I needed was not an additional pre-amp so much as a simple device that would use high quality transformers to convert the signal coming in through the XLR connectors to a signal that would make the inputs on my camera happy and more productive. I found that in a small and inconspicuous project from Beachtek called, the DXA-2T. On one side are two XLR inputs. You can run long cable from your microphones to this box and plug them into real XLR plugs. The innards feature well crafted transformers that convert the signal from "pro" mic to "amateur" camera inputs.
On the opposite side of the box is a single 3.5mm output that allows for a stereo or dual mono signal to be delivered to your "hybrid" camera's mic in plug. On one end are two click stopped knobs that allow you to pot down the output signals which gives you a certain amount of level control. The device is passive so it won't actively amplify your signals. You can turn stuff down but you can't turn stuff up...
This box allows me to take a signal from a microphone like the Rode NTG 4+ with its built-in in battery and amplifier and route it to my camera after "fixing" the signal to make it compatible with a typical camera input. Perfect for any brand of camera that doesn't offer its own audio interface. (Sony and Panasonic offer "active" adapters for use with some of their cameras....). The DXA-2T is simple, has no moving parts, requires no maintenance and doesn't require batteries. So, I found the perfect audio interface, right?
Well.......for some stuff......but...
Once I got my camera and pro microphones to speak the same language, via the Beachteck, I was much, much happier with the sound quality I was getting from my system. But being the ever ready consumer I started to wonder if more expensive microphones might provide even better sound quality. This led me to microphones like the Diety from Aputure and the 416 from Sennheiser. Both are short shotgun microphones and both share one other thing, in order to work they require phantom power from an external source. The three wire configuration of XLR cables can provide a 48V from an audio interface or professional video camera which can power one of these microphones (be sure to check whether or not you need phantom power because applying it to a microphone that doesn't need it can fry the microphone's circuits...) but a plug adapter and a DSLR or mirrorless camera's 3.5mm mic input will not.
The DXA-2T also has a line/mic switch for each channel which allows me to bring in a feed from an audio board or mixer which would normally overload a camera input. That alone is worth keeping one of these in your bag.
I bought four different microphones that each has its own super power but all four are dependent on external/phantom power. Now I needed to purchase an adapter that could not only make the electrical matching I needed for pro microphones but I also needed one that could power this growing collection of professional microphones.
One method is to use a digital audio recorder as the interface. Something like a Zoom HN-4 or a Tascam DR60ii. These have the inputs and outputs needed by also feature internal audio recording with the idea that we'll step back in time and record video to our cameras, audio to a separate device, and then marry the two up in post production. But after using digital audio recorders for a few projects I resented having to take the extra steps to sync up audio, not to mention the burden of having big boxy appliances hanging off the camera rig and also sucking up battery juice. I wanted what I needed and nothing more. I wanted a box that would take balanced XLR cables from microphones, run them through noiseless transformers and output an unbalanced but corrected signal that would make my chosen camera happy. I didn't think it was too much to ask...
I am currently using the Panasonic audio adapter in conjunction with the S1 cameras but I still need one of the audio interface contraptions for my Sigma fp camera which is a powerful video (visual) camera but a really bare bones audio capable camera.
The Beachtek DXA-Micro Pro is one I like for that particular camera. It only offers one XLR input (does have additional 3.5mm inputs) but most of my use with that camera is video street shooting with only one microphone. It can supply phantom power for a microphone that needs it and is also a pre-amplifier which can add gain to a "quiet" or insensitive microphone's signal. But the icing on the cake for me, when using it with the Sigma fp camera, is the headphone jack right there on the box. While being able to monitor exactly what the camera is inputting, at the camera, is optimal that's not an option with the fp. It has no headphone jack. The DXA-Micro Pro has a headphone jack and a volume control for it too. But you have to understand you are only hearing what the DXA-Micro Pro is sending to the camera not what is actually being recorded in the camera.
While I don't use the DXA Micro Pro anywhere near as much as I use the Panasonic dedicated audio interface it's become a job saver for those times when I'm using cameras that don't work with the Panasonic device. It's not too big so I leave it in the video case all the time. Takes one 9V battery and seems to work well with most microphones and cameras.
When I am working with Panasonic cameras like the GH5, the GH5S, and the Lumix S1 I love using the Panasonic DMW-XLR1. It sits in the hot shoe of the camera and connects via contact in the shoe. It accepts two XLR inputs (either line in or microphones) can supply phantom power to the mics that need it and has a wide range of good controls. It can boost weak signals, filter out lower frequencies, record in stereo or dual mono, and it even has automatic level control (ALC) for those times when it just makes life easier. The DMW-XLR1 pulls its power from the battery in the camera so I like using it best with a camera that's got the battery grip attached.
It's small, elegant, works well and gives me really good audio. Sony has a very similar unit for their A7 series cameras which I have also used and can recommend.
The only downside of the DMW-XLR1 is that it can only be used with Panasonic cameras. I'd love to be able to use it on a Leica SL2 (if they ever come off back order...) and I'd dearly love to use it with a Sigma fp, but there we are.
The control side of the DMW-XLR1.
loving the covers for the XLR connectors. Keeps water and trash out off the connectors.
There's one final product I've used to good effect and which was recommended to my by audio expert, Curtis Judd. That's the Saramonic SmartRig+. It's all plastic, and built like a 1960's transistor radio but it delivers twin XLR inputs, dual channel gain controls and a headphone output for anyone who needs a budget option which actually sounds good. The icing on the cake is that you can use this one as an input device for mobile phones. There's a phone ready plug permanently attached and a switch right on the body of the device to make it compatible with most phones.
The only camera to date that has not worked with the Saramonic SmartRig+ has been the Fuji XH-1 which caused a low level, rhythmic hum cascading whenever I tried to connect the camera to this particular interface. On the other hand it was absolutely great and rock solid with cameras like the Sony RX10 iii and the Panasonic FZ1000.
Another good work around for audio into consumer/hybrid/non-XLR cameras is to just use wireless microphone systems. I've purchase pricy Sennheiser systems but this Saramonic set gives me two channels into a typical camera's microphone input connection while providing great level controls. I've actually run an Rode NTG 4+ microphone through a Beachtek DXA-2T and into the input of one of the Saramonic transmitters and gotten it to work well as a wireless shotgun microphone. You never know what will work until you try it out.
I'm going through all the systems today because we have a shoot on Sunday that's split between video and stills. The video consists of several fast paced, newsy style video interviews and I want to make sure my audio is locked down tight. Testing and familiarization is the only course I know of that works 99% of the time.
I hope everyone is happy and well.
More to come.
4 comments:
Thanks for getting me to use my brain today. I'm a mostly retired engineer who has worked with test and measurement system that are prone to a lot of the problems of the type encountered by your audio systems. A challenge for microphones I assume is, like many types of sensors, they typically produce very low level signals that are easily corrupted by noise in the environment they operate in (I assume the powered ones amplify everything right there at the mic to largely avoid this). I've always wondered what balanced audio inputs mean exactly and your post got me to finally go and google it. Very interesting solution to reducing noise on low level audio signals. Has me wondering why something similar never made its way into the T&M world I worked in. I never do video but this is very interesting to read from a standpoint of trying to figure out the engineering involved with getting good audio to go along with it. My hats off to you for being able handle all the creative stuff as well as the technical aspects of getting all this gear to work.
Just a small clarification so I don't sound like an idiot. The 'noise' I referred to in relation to the microphones is electrical. That is what interferes with the electrical signal from the mics. Re-read it and now it sounded like I meant noise as in noise we hear. That was not the case. Have to work on my writing skills.
Thanks for updating this topic. When I finally get around to using my G9 for video, your experience with the Beachtek and Saramonic products will be on file (if my brain hasn't fried by then). I don't know what prevents Panasonic from adapting the two-mic XLR device for the GH5 to work with the G9, but that's life. I have enough trouble coping with the concept of impedance, but at least I know enough to pay attention to it. Please keep us up to date with your experience with the nuts and bolts of these things. It's a bigger help than your stills-only readers can comprehend.
I could have used this info 10 years ago when my wife was making puppet videos using consumer HD camcorders. I travelled down the same rabbit holes. Who knew that there were sound people around who had solved these problems long ago? Nothing is simple.
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