Robert from juicedLink stops by the studio again to give us another helpful audio tutorial. This time, Robert and I take a look at what you can expect with the Blackmagic Cinema Camera’s current audio pros and pitfalls. The Part I video below is intended to provide an overview of audio on the BlackMagic Cinema Camera with optimal audio solutions for your BMCC audio workflow.
First we address the BMCC’s balanced Analog Audio Inputs: 2 x 1/4″ with out phantom power. Robert tells us how you can adapt these to interface to either XLR or a Stereo Mini Jack and provide phantom power. Some of the minijack to 1/4″ y-cable parts mentioned:
Remote Audio CAB-M1/4
The BMCC does not have audio meter available (at the date of this post) in-camera. We detail a few solutions to get audio metering both in-studio and while field shooting. When the BMCC is connected to your computer, the Blackmagic provided Ultra Scope Software will give you audio metering capabilities. You will have two options for recording audio, VU and Db, you’ll want to choose the Db for Digital Recording. For monitoring audio while field shooting, a preamp with meters is another option. The Riggy-Assist has audio metering as well as the capability to provide phantom power. If you’re using an external monitor, this is yet another way to have audio meters, so long as your monitor provides you with this option. You can still use a preamp in this situation, the Riggy-Micro, for example, does not have audio metering, however it will give you better signal to noise, provide phantom power and it is smaller and more power efficient than the Riggy-Assist.
If you slide the digital gain too low, the digital gain will become digital attenuation. When you implement digital attenuation behind an analog to digital converter, you limit the head room that you’re getting in the camera. This means that when you introduce a large signal level into the camera, rather than being able to handle this level, the camera will start clipping. To avoid this, there is an optimal gain setting that you will want to set in the Blackmagic Cinema Camera, this is in the 20 to 30% range. Once you set it here, you don’t want to change it. This is right at about 0Db and this is currently with the 1.1 firmware.
Robert explains to us that when you take the Wave File from the camera and pull it into your timeline, there will be a DC offset in the Wave File. A DC offset is asymmetrical around 0 and symmetrical around some DC offset. The DC offset varies around gain. At the 20 to 30% range that Robert suggested setting your BMCC’s gain to, the DC offset will be there, however it will not be very big. When doing any type of post production manipulation of your audio, you will want to take the DC offset out first.
Last, Robert shows us some juicedLink mounting options for your Blackmagic Cinema Camera: Mounting Bracket, Top Handle and Coldshoe attachments (all can be found in the links below).
Robert does a fantastic job of delving into the more technical audio details of what we covered in this video and blog post. You can find all of his audio solutions and more on the juicedLink blog: www.juicedLink.com