If you have been following Camera Dojo over the past year you may have followed along as I discovered Why DSLR Audio Recording Sucks and What To Do About It and then used a JuicedLink DS214 Amp to improve the audio which worked extremely well. More recently I tried using a Zoom H4 as a Boom Mic. While these things did pretty good, my goal was to get broadcast quality audio and I simply was not getting there without extra work in post production. The big question is what to do to really take the audio to the next level of quality. It was time to consult an expert and there is nobody better than Robert Rozak at JuicedLink. Robert made two suggestions, first I needed a better microphone and recommended the Audio-Technica AT875R. The second thing I needed was a preamp with XLR inputs and we settled on the JuicedLink RA333.
Busting The Budget
As you follow along the articles listed above, you will see that I started as inexpensively as possible and quality suffered. As the price went up, so did the quality. At any point along the way, I could have decided that the quality was good enough if I wanted to. For me it is just like photography where I want to get things right in camera and not have to fix it in Photoshop. With audio, I want it right in camera as well and don’t want to have to do extra processing and noise reduction during post production. The more time I save in production, the more profit is left on any given job. To do this right, was going to start costing some money. The new setup was going to consist of the following new components:
- Audio-Technica AT875R $173
- JuicedLink RA333 preamp $469
- 25′ Balanced XLR Cable $15
- Misc accessories $35
That’s $692 before taxes and shipping charges. After discussing it more and watching through a bunch of videos that Robert over at JuicedLink has done, I was convinced that I was going to just have to bite the bullet and do this right. I could have saved a little money on the preamp with a less expensive version but I really wanted more inputs, meters, headphone jack port, and AGC disable and since this is really an investment in my business, I decided to quite monkeying around and do it right.
Well..maybe I didn’t go “all in” as my budget was stretched pretty thin but Robert assured me the Audio-Technica AT875R would work very well, although if I had another $100 to spend, the Rode NTG2 would be a little bit better.
Why a Preamp?
I consider myself to be a pretty smart guy but an electrical engineer and audio recording expert I am not but watching through Robert’s videos I came to understand the whole concept of signal to noise ratios, noise floors, balanced inputs, and noisy amps. What this boils down to is that the amps inside your camera are just not very good…to put mildly…and using them to increase the input signal is going to add unwanted noise…somewhat analogous to shooting at a high ISO speed, it will work, but wont be ideal and you may not be able to edit it all away.
What we want to do is to use a preamp to take the signal from the microphone and boost it to the proper levels since the amps in the JuicedLink RA333 are far superior to the ones in the camera, and then set the mic input on the camera as low as possible. This provides the cleanest signal into the camera.
Now all this is just to eliminate noise that is created in the electronic circuitry as a result of audio levels and signal strengths. This does not address background or ambient noise or acoustic echo. This is part of what goes into your microphone selection and your recording environment.
Why Record Audio To The Camera?
Traditionally video and audio is not recorded together, the video is recorded to a video camera and the audio to a tape deck and then synced back in post production. When you are using lower grade equipment like DSLRs, Camcorders, and inexpensive digital recorders you can actually get a sync problem where, even though you have the audio and video synced perfectly at the beginning, at the end of the scene the audio and video do not line up because the playback speed of the two devices are different. Now you have to tweak the playback rate of the video to try to match the drift amount of the audio signal. Recording directly to the camera eliminates this problem.
Just as important as syncing is that using the RA333 is easier to adjust signal level with simple front panel potentiometers vs. trying to adjust the gain level on some of the field recordings by hitting the gain button on the recorder a bunch of times. You also never forget to record your audio again. I have done this myself several times when finishing a shot and realizing the recorder never started. A nice little perk is that the RA333 has instantanious boot time to capture spontaneous events versus raiting for a field recorder to boot up, select the mode, select the inputs, go into record mode, and then hit record.
Setting up the RA333
The RA333 is a nice, unassuming black box of magic right up until you turn it over and see the 19 different switches and two dials. While it may be a little intimidating, the amount of setup work is pretty minimal. First off, I popped in a 9v alkaline battery and then turned to the RA333 online manual. The following is a quick bullet list of the settings I used:
- LiPoly/ALK to ALK - this is for proper battery metering
- MIC/LINE to MIC and GAIN on HI for the L1 channel
- Power set to 12v
- AGC DISABLE: On for Canon 7D / Off for use with Canon Vixia camcorder
The final step is to calibrate the meter to your particular camera. Instead of trying to walk you through this, I have simply included Robert’s video on how to do this set.
On to the testing!
It’s all setup and ready for our first test. But before we just throw stuff up and start recording, we need to revisit the concept of signal to noise real quickly. Just like in photographer where light has a very specific and fast fall off as the distance increases, so does sound. If we think of sound like light, the placement of the microphone will make more sense. With light, as we move away from the light source, our image gets darker and thus we lose image quality.
For you really geeky types, audio uses the inverse square law, exactly like light does.
With the microphone, the further away from the subject, the less sound is hitting the mic and the audio level gets lower and lower which means we have to boost it with more gain, and we will lose audio quality. Because we want the best audio signal possible, we want the mic to be as close to the subject as possible and yet still be out of the frame.
This positioning gets very tricky with certain cameras because very few cameras have a 100% viewfinder. The worse one I have is my older Canon Vixia HF20 camcorder which sports a pathetic 90% viewfinder. What this means is that what you are seeing in the viewfinder is actually cropped from the full scene so when you go to edit it, the scene is larger than you expected and you often have to zoom in during post production to remove mics and lights. On the other hand, my Canon EOS 7D has a 100% viewfinder so I see exactly what I am going to get.
Here is another video that will help explain proper mic positioning:
So we now we know we want the mic as close as possible to the subject and preferably overhead pointing down. Given these parameters, let’s see how everything sounds.
While intimidating at first glance with all the switches on the bottom, the RA333 is actually very easy to use and all I need to do when moving it from device to device is a small adjustment on the front control levels and it’s good to go. I am extremely impressed with what this did for my audio quality as I have done several videos with ZERO post production on the audio now. With the excellent hardware of the RA333 and expert instructions from the videos at JuicedLink, you have a winning combination to solve your audio requirements.
JuicedLink Website: http://juicedlink.com