Tuesday, December 15, 2009
The Importance Of Sound
In discussion with DPP, sound master Mark Adams describes the ins and outs of working with sound for multimedia and HD video productions
Los Angeles-based location sound mixer extraordinaire Mark Adams has traveled the world capturing sound for productions including the Olympics, NBA Entertainment, Major League Baseball Productions, CBS, MTV and National Geographic. For the CBS Evening News with Katie Couric, he covered the 2008 presidential and vice-presidential debates (who can forget the Katie Couric-Sarah Palin interview he recorded?). Adams also was the supervising location sound mixer on Another Kind of Valor, a docudrama addressing the mental health issues of American veterans returning from combat.
Digital Photo Pro solicited his expertise to give us a better understanding of how sound capture works as the new generation of hybrid DSLR cameras offers still photographers the opportunity to capture the moving image with the same piece of equipment. This information is becoming vital as professional photographers will be asked more and more to supply moving imagery from their “still” photo shoots.
DPP: The new DSLR cameras, with their ability to record the moving picture, are revolutionizing image capture. How is the sound quality with these new hybrids?
Mark Adams: Both my colleagues and myself have been very impressed by the quality of the HD video produced by DSLRs for certain documentary and behind-the-scenes, moving-image-capturing applications. I’ve had the opportunity to use a DSLR with HD 720p video-recording capabilities. The built-in monaural microphone on the DSLR, with no ability to use a balanced mono or stereo audio input, makes it an impractical tool for dialogue-based recording. Even if hybrid DSLRs had an unbalanced mini-external stereo input, the process of recording quality audio would still be inferior to conventional high-end HD-format camcorders, most of which have balanced XLR inputs for high-quality stereo audio.
DPP: What type of equipment would you suggest for photographers trying to capture better sound for their projects?
Adams: It would be best to record the sound separately using a high-quality digital audio recorder such as a Sound Devices 744T, which records onto an internal hard drive and a CompactFlash card, or the new Sound Devices 552 five-channel digital audio recorder/portable mixer, which will record onto SD and SDHC media. These devices are able to record WAV and BWF files at multiple sampling rates, bit depths and time-code frame rates and are established sound-recording tools in the television and motion-picture industries. They’re also portable and can be powered by four AA batteries or by an external 10-18 VDC. I know from personal experience that the Sound Devices digital audio recorders also are extremely reliable. I recorded over 40 interviews in 11 countries on five continents in moderate to extreme conditions within a three-month period using a 744T without a single technical incident.
In addition to a digital audio recorder, you’ll need to have appropriate microphones. The most important and versatile microphone for capturing basic sound, in my opinion, is a super-cardioid shotgun microphone such as a Sennheiser MKH 416 or MKH 60 with a carbon-fiber telescoping boom pole and shock mount. For heavier, dialogue-intensive applications, I also recommend lavalier microphones with wireless microphone transmitters and receivers such as the Lectrosonics 100 Series or UM400a/UCR411A system and complementary accessories. A digital time-code slate also is a good investment so you can easily sync your video and your sound. Finally, a professional set of headphones such as the Senn-heiser HD 380 Pro is a must.
DPP: How do you record and sync sound with HD cameras shooting at both 24 and 30 fps? Also, why does video record at 23.976 fps instead of 24 and 29.98 fps instead of 30 fps?
Adams: Most conventional high-end HD-format camcorders have balanced XLR inputs for high-quality stereo audio so that one can record audio on the same tape, disc, card, etc., that’s being used to record the video. Whenever you alter the frame rate for the video on most of these camcorders, the frame rate for the audio input on the camcorders automatically adjusts to match the chosen video frame rate. However, when recording audio on a separate device from the video, the frame rates must be set properly so they can sync up. In order to sync sound with HD video on a hybrid camera, you must first know what frame rate you’re recording on with your HD camera.
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