Six Ways To Guarantee Bad Project Audio
by: Jerry Robinson

Attitude: let someone get by with saying "Its good enough for video" or "It's a visual medium (audio doesn't matter)". Throw anyone with this attitude off the project immediately, they will kill it as surely as having your funding pulled, just not as fast.

Limit communication and involvement between the video, production sound, and post production people. Decisions made in a vacuum will get expensive when you make a choice that impacts the others without their knowledge. Make sure you determine the impact of the choice in terms of both time and money. There are a lot of people who will say to themselves "I can do that" but don’t think through the time and effort required. Just because you did manual sync on a 15 minute demo doesn’t mean you want to try that on an hour long documentary. Try to remember it took a couple hours to sync that 15 minutes.

Use the really bad on camera mic. With a camera microphone you should be within 2 feet, with a good shotgun mounted on the camera you need to be with in 3 feet. In a really quiet environment like a studio maybe you can maybe add another foot. Boom or wired lav are my first choices, wireless only if there is no other option. Be aware that using an on-camera mic will limit the number of people in the scene.

Don’t take your sound guy with you on locations scouts and make sure that you are there at some other time of day than you plan on shooting. If using wireless don’t check available frequencies.

Don’t record wild tracks on camera (if you are using camera sound) for the audio post guy. He can use repeats of dramatic material to patch the place in an otherwise great take where the garbage truck 2 blocks away stepped all over the audio and to get location sounds so he can patch around bloopers.

Don’t seriously consider 2 part sound for dramatic work or music (music videos are an exception as the band usually mimes to a CD or hard disk playback). Most cameras have marginal sound and are not up to the current music audio standard of 24 bits at 96kHz. (Don’t be upset if you don’t actually get a full dynamic range corresponding to 24 bits; 18 bits or more is fine.)

There are other mistakes that you can make, but the above are the common killers. One that happens a lot but that isn’t specific to audio is the failure to treat the project as a business and get reasonable funding. This “…hey! Here’s a barn lets put on a show!” might occasionally work—I have yet to see it—someone inevitably winds up short of time or money. Its often the audio or lighting and almost always post. Good editing is a craft and unless you have someone to work for a low charge or points you will stall out.

One documentary project asked if I could fix key audio on was shot with a lot of Doppler motor noise in the major location. There is a specialized set of software tools called Audio Cube, which has modules that can fix the problem. That module is around $3500. I know one guy with the system but his charge is $50 plus $20/minute (his whole system was over $50,000) and the production didn’t have the money to fix an hour of audio, nor could they ADR. As far as I know that production died.

Another problem that I see is that some folks are not skeptical enough. Someone will recommend a cheap microphone without reading reviews or talking to anyone else. Hey its $200 for this wireless microphone. This kind of goes with the failure to treat the project as a business.

Something I don’t really understand is why many people don’t consider renting. Yes you need to find a rental place and then get a relationship setup with them and most will insist on insurance. But I can’t really justify $4,500 plus for a Zaxcom wireless that can be rented for $70/day and get 5 days for the cost of a 3 day rental.

A lot of folks are worried about 2 part sound particularly with multiple cameras. In many cases you do not need to worry about sync! Depending on the subject and shooting style if you are not going to have close inter cuts which must match exactly or if you are doing a MTV type of edit then you probably don’t need to synchronize either cameras or the external sound.

Sound synchronization does not have to be expensive or difficult. If you are shooting relatively long takes, your recorder will walk out of sync with your camera. There are several good approaches to fixing this problem:

Record a reference track on camera; this requires getting the mixed audio to the camera but that's usually possible. Be aware it can get time consuming and expensive in post though.

Use a slate properly. Clap the sticks so they are auditable and say “this is scene whatever, take so and so” loudly so both the camera and recorder get it. I once did post on a project where the camera recorded the written slate but the scene and take were not identified on the audio track. Syncing the audio took a long time and cost a lot of extra money. Either the recorder or the camera must be the master. Most recorders sync to word clock and cameras to video sync (black and burst). I know of only a couple recorders made by Tascam which sync to video and I'm not aware of any computer interfaces which do. There have been devices which take video sync and convert to word clock but they are no longer made as far as I know.

Put camera time code on the audio tape. Unfortunately most DAW and NLE do not recognize audio time code and many cameras don’t output time code, You can take video sync (sometimes called black and burst as in the past it had to have the video striped leaving only the sync signals, now most video gadgets are fine with video as sync). Unfortunately while a camera may sync to video (often called genloc) almost all audio recorders sync to Word Clock (a very accurate train of pulses which occur at the sample rate). Only Tascam has recorders which sync to video. Fostex and Sound Devices make recorders that use TC but it is not clear whether they just use it to time stamp the file when recording starts (jam TC) and then use their own internal clock which will drift out of sync in 20 to 40 minutes, or whether they have continuous sync.

Lastly you can take a device which can be synced to others of the same brand and which can output the necessary sync signals (video sync, tri level sync [HD only], or word clock as well as time code). Deneke makes one of these and Ambient makes the lockit and master clock for syncing lockits (expensive around $2500 for two lockits and a master clock). See www.ambientaudio.com/products/timecode.html for pictures and descriptions and the lockit online manual. The master clock syncs the lockits with in 0.2ppm so they retain sync for a day. You put one on each camera and supply TC and genloc and one on the recorder for TC and WC. I could go on here in more detail but there’s a very good book on the topic 24P For Sound and Video Assist by Wolf Seeberg the title is misleading as it covers all film and video in great detail.

More and a preview at http://trewaudio.com/store/product.php?productid=18&cat=3&page=1.

Another thing that I have problem with is folks not using inexpensive available resources. If you are the producer/director you should know some of the basics. Jay Rose has very good books on audio for video, both production and post; and John Jackman’s book on lighting and Ross Lowel’s Matters of light and Depth” both are excellent. You can save your project a lot of money by simply reading these.