AT 4051 short shotgun mic

The demands for the audio of any given documentary project will vary wildly on the program content as well as the documentary style. A talking head program will usually have controlled interview situations and time for audio adjustments if needed.  A cinema verite or run and gun documentary may often just have the chance to get a microphone close to the action and hope for the best.  This post can’t address every situation that can be encountered however, it can advise best practices to the sound recording process.

Making documentaries requires a vast media tools skillset.   Several skills will have to be employed: from the camera and sound recordings, the transfer and storage options, to the edit, the mix and the output.  Usually by an army of one, namely, you.  A thorough understanding of the tools and techniques for sound recording is going to be essential for any documentarian.  Filmmakers often have extensive knowledge of new cameras, codecs, lenses and workflows but not understand the difference between a hyper-cardioid or an omni-directional microphone and might not know the difference between a short shotgun microphone or a long one.  But, before you can even get to the recording process, you should be applying one of the most important of your skills: listening.

LISTEN

To properly plan for sound the first exercise is simple – listen.  Listen to the room that you are in, listen to the location that you will be shooting and understand the consequences of the audio landscape.  Filmmakers must train their ears as much or more than they do their eyes.  As humans we spend enormous amounts of time filtering out sound.  We block out the trucks and buses, the airplanes and birds, the hums of computers and fans and air conditioning, but the microphones hear it all.  They simply record the audio environment.  The environment that you may not be “really” hearing.  Stop.  Listen. Stop again.  Listen.  Try to pull out the layers of the sounds you hear, first the fan, then the computer, then the traffic, then the wind, then the birds.  If you stop and really listen you’ll be amazed at how much is going on.  Do it right now.  Do it all day long, every day.  Learn to hear.  Learn to “listen” to your locations.  Make adjustments if you can.  No matter what, those audio recordings will be with the project right up until the finish.  Make sure every recording sounds as good as it can.

Closed ear headphones help minimize external noise

I once consulted on a doc that had numerous sound issues.  The first problematic scene was an interview of a person on a street corner.  The filmmaker chose to orient the shot so that the boom and microphone were pointing directly at a noisy street.  I asked if the composition of the shot was so vitally important to create such a noise issue.  I was told that there was no one monitoring the sound through headphones and that the shot looked good with the traffic passing behind the subject.  The sounds of this busy intersection completely overpowered the conversation being recorded.  There was a lack of understanding of just how much the audio had been compromised by pointing a directional microphone straight into a loud, evolving noise source – the street.  Of course with no one listening to the recordings it would be hard to determine the quality of the audio!

It might be easy to say, well this is something I would never do but due to the circumstances of whatever is going on as you shoot you do what you can and keep moving on.  In their case the only pair of headphones they had been using stopped working.  There are many problems that can and do happen in the heat of any given production.  The situations may not be quite as obvious as pointing a mic into a busy street but the damage is often just the same.

I’m not a purist and I understand that not all contingencies can be planned for.  But often there is no actual time logged discussing the sound beyond boom or lav and the gotchas come fast and furious in post.  For those of us who are tasked with fixing the audio track it can be a real head scratcher when you hear recordings that could have been easily fixed on set with a simple turn of the mic or an appropriately placed blanket.  Hear the location that you are shooting.  Minimize the audio obstructions.  Turn off fans, unused computers and point the microphone away from noise sources.  If a location is really loud have a second look to see if moving to another place is feasible.  Oftentimes simply an awareness of the sounds can prompt you to simple solutions.  Listen.  Many times.  It’s as simple as that.

PREPARE

Go to a home improvement store or look online and buy several moving blankets.  Sometimes these are called furniture pads.  They are quite inexpensive and are worth their weight in gold.  Blankets should be a part of your kit the same way a tripod is for the camera.  These blankets can be used to cover loud noise sources; they can be used to deaden reverberant spaces, they can be hung in doorways to block sound.  Just fold them up, throw them in the trunk and use them when needed.  Blankets can often be a simple noise fix and can save many hours and dollars in post.  Well worth the few dollars.

$12.00 blanket can save $$

Spend some time researching microphones and their use.  Chances are that you’ve learned a great deal about the camera, the post considerations, the media storage and the workflow.  Spend some of that time learning a bit more about audio.  Which is the best shotgun mic for your situation, short or long?  Would it be better to boom the shot or mic the person with a lavaliere?  How about planting a microphone to capture a wider area of sound?  Would a boundary microphone provide the coverage that would be required for the shot?  If these terms and concepts are new to you, if you didn’t know that shotguns come in different lengths and each one has a particular usage then next time you are on the Internet search “audio, microphones and techniques.”  You are going to be living with these location recordings through the rest of the process, take good care creating them.  Make sure that the audio captured is as sharp as your images.

Sound devices mic preamp 302

Another main tool in the recording arsenal is the microphone preamplifier.   They are sometimes referred to as mic-pres or preamps.  Most microphone preamps are a part of a mixing unit or board and are built into most digital video cameras.  The preamplifier is the device that a microphone plugs into and allows for precise control of the levels being sent to a mixer or recorder.

This graphic shows a mic-pre with three inputs.  You can see the XLR plug inputs on the left and the three corresponding knobs on the front panel to control the signal gain.  You want to record the audio levels loud enough to be well past the threshold of noise (signal to noise ratio) but not so loud as to distort the recording.

Preamplifiers are a key part of the quality of the recorded sound.  Some preamps are noisy, some are quiet, some provide strong clean gain, some not.  The quality of the recording will be determined by the quality of the microphone choice and usage, and the quality and signal to noise ratio of the preamp.  If these terms are new or strange get on that Internet machine and do a bit of research.  Just an FYI, in a general sense, the mic preamps that are included in a camera are typically not of sufficient quality to deliver excellent recordings.  If you want professional results that you will be able to sell and distribute later, (right?) use professional gear.

Bring a grab bag for your audio.  Fill it with safety pins, various types of tape, extra audio connectors and mic clips.  Bring along a mic stand or two along with some clothespins, rubber bands and paper clips.  Bring extra batteries, extra cables and most especially a bit of extra time for your audio.  If you don’t have a pin to affix a cable, tape to conceal a plant mic or a stand to put a mic in an awkward place you will lose an opportunity that may not come again.  You may never have another chance with that interviewee or that event.  Plan for the worst and hope for the best.

FINAL THOUGHT

One final thought regarding your location audio.  Besides learning about sound and how it spreads in space, besides learning about recording devices and which tool to use for the moment you need it, besides using quality equipment and excellent recording practices like not recording too hot and keeping the microphones close – I may also suggest; hire professionals.

Professional sound mixers have been there and they have done that.  They can anticipate problems before you’ve even considered it.  They can offer solutions to problems that you weren’t even aware existed.  They have probably been on more shoots than you, worked with many different talented people and are up to date in their knowledge about their specific skill: sound.  I know that budgets are tight and particularly on documentaries, but skimping on the sound process or the quality of the recordings will have a direct impact on the final product.  Bad sound has ruined many a worthy doc.  If you can’t afford to hire a sound team for the whole shoot see if you can get someone to consult with you.  A few hours in good conversation with someone looking over your gear and your recording locations can save you a lot on the back end.  You have a story to tell, make sure that your audience can hear it.

Nagra Tape Recorder

The music can include the composed score, popular songs, and source music like radios, cars and or muzak.  Muzak is a brand-name but typically refers to background music heard in stores, elevators and the like. The sound effects can include sounds such as atmospheres or backgrounds, hard effects like car door slams or guns and explosions and or Foley recordings.  Each of these various sound elements may require a number of different edits and discrete sessions for final mixing.

For the purposes of this article we will discuss these ideas using Pro Tools as our recording, editing and mixing platform but these concepts can be easily ported to any other digital audio program.  For those who don’t use ProTools I will define the terms as I go – starting with “sessions.”  In Pro Tools world a “session” is simply the name of any one particular document.  In Microsoft Word you create a “doc file” in Pro Tools you create a “session file.”

Most computer programs allow for the ability to save a document “as” something new.  Basically you “save as” the file saving the past work and adding to it in the new “save as” session.  My strong recommendation is to “save as” whenever you are substantially changing a session.  In fact I like to do many sorts of “save as” sessions.

I have encountered many engineers who like to save over their prior days work.  Most programs have some sort of “back-up” schemes and Pro Tools is no different.  These sessions are automatically saved and can be used to go back to prior work.  However these sessions are meant as back-ups so they will not be well documented.  In the case of Pro Tools it creates a new back-up file by time increments designated by the user.  For instance, by choosing your preferences, you may create a back-up every half-hour or quarter-hour.  This is essential practice for any engineer as a safety but it is not useful over the long term for a complicated project such as a TV show or a feature film that may contain many different “sessions” prior to the final mixing.

Here is a simple system that I have devised using “save as” in my session saving.  The rule is – new day – save as the next increment – Dialog Edit 5 becomes Dialog Edit 6 and so on.  Or if a new engineer is adding to the session, as in the case of a multi-user facility or project, save as the next increment.  Also save each edit, record or mix session by name – “Dialog Edit 1″, “Foley Record 1″, “ADR record Jesse 1″ and so on.

Over the course of a complex project will there be many sessions created in this manner?  Yes, absolutely, but it also allows for precise documentation of each session.  Also the media used within the project is what takes up drive space, the actual size of the “session” file is quite small so you are not using gigs of additional storage.  One of the difficulties in complex projects that are spread over many days or weeks is keeping tabs on the changes that occur as the show progresses.  One thing any good editor/mixer will learn early on is that there must be a simple way to get back to prior work.  Directors and producers change their minds often and you must be prepared to get to those changes quickly.  A director will not want to hear that a session or sequence must “be rebuilt” to conform back to what was recently completed.

I also create a document that references each session file as a paper document.  This is old-school – utilizes a pencil and paper!

These session sheets are printed, documented and kept in a show specific binder.  A sample document can be seen here.  This can and should be altered to fit the working style of the team as well as the project but this one hits the main points for documentation.

Name of session and date are obvious.  I also include the engineers name as well as which session, if any, it was created from.  I also include where the media and the session are physically located, i.e. which computer, which drive, which directory etc.  Nothing is worse than not being able to find an edit session!  Oh it’s on THAT drive!

There is also a notes section that is to used for – notes.  Detail these notes, this has been a long days work and there have been many changes, additions, deletions and breakthroughs.  Be sure to accurately note what has been done, what has not been done, what challenges are still faced in the session and so on.  It may seem that keeping all of this information in your head is fine but good luck in a month.  Theses documents will prove invaluable as the process continues and are particularly useful when multiple editors are working on the same material.

All of the session sheets are kept in a binder accessible to anyone that is working on the project.  In the case of a feature film for instance I break the session binder into sections and by date for easier retrieval.  One section is devoted to the dialog session sheets, one for Foley, one for sound design and effects editing and so on.  Each is placed in the binder on top of the next per section so the most current sessions are on top.

This documentation is not just for today.  A lot of projects change or get changed as time passes.  The producer gets a foreign sale and they require a new set of deliverables.  Or the music rights of some tracks have expired and the sound needs a re-cut.  I’ve had many projects come back at a much later date for a few “tweaks.”  These binders help track down the small things that directors need to alter the film.  I’ve swapped out entire music tracks and re-mixed, I’ve changed ADR lines, I’ve recorded voice-overs to clarify story points, all well after the final mix.  It’s in your interest as the post sound lead to be able to make these changes in a timely and effective manner.  Three years down the line tracking down some ADR takes may be more difficult than you think.

Archiving the sessions will also take some planning if they are to be useful at a later date.  Pro Tools has a great function called “save copy”.  What it does is it takes all of the audio files that are used in a particular session and creates a complete new session.  I can’t go into too many Pro Tools specific things here but there are a couple of tricks I use for archiving that Pro Tools offers.  It has some great ways of importing and deleting audio files and tracks.  When a project is complete I like to create what I call “master sessions” which are a reflection of the elements of the final work.

For instance, I will compile all of the ADR takes for each actor into one session.  I will then strip the session of everything except for the initial picture editors guide track, a stereo mix of the final completed mix and all of the takes recorded for all of the characters.  I will then save that as the “ADR master session.”

Of course you will need to create a “final mix master session” which will contain only the final edits, audio files and work that created the final mix.  Repeat as necessary. Foley master session, dialog edit master session, whatever is needed to easily reach for those sessions at a later date.

If this article was to be stripped down to its essentials I suppose you could pin it on one word – organization.  If you are the supervising sound editor on a big, long project such as a feature film you will need to find and document things clearly.  Get in the habit of it.  It will make the edit easier, it will make the collaboration easier and it will ultimately make your life easier.  Wouldn’t you rather have the chance from time to time to leave early and relax rather than stay late digging through drives looking for a random audio file?

Human hearing of frequencies is calculated on a scale of hertz or cycles per second.  The commonly defined range of human hearing is 20 hertz to 20,000 hertz per second.  A graphical EQ device, be it a hardware version or a software plug-in like those shown here generally work within that range. (Depending on your age and life experiences your hearing may be markedly less than this…)  In the application of boosting or cutting particular frequencies there are also a few controls which determine how the boost or cut will be applied.  The first is the particular frequency itself, the second is the amount of boost or cut, usually described in decibels, and third is the “Q” or width of the boost or cut.  If the horizontal line is flat, as shown here, then no EQ processing is happening.

10 band parametric EQ

Looking at the photo here you can see the controls just described.  This particular EQ is a 10 band EQ meaning that you can affect 10 different bands or frequencies at one time.

The graph indicates the frequency to be affected sorted with the low frequencies at the left of the graph to the high frequencies at the right.  Each ‘band’ has several controls – on/off, the type of “curve” to be applied, the gain or amount of the processing, the frequency where things are being applied, the Q of the processing and the overall input of the source and the output after processing.

Bell EQ curve

Here is a bell curve which looks sort of like a – bell.  This is a very common way to apply EQ to a particular frequency.  The Q is set to very wide so it is affecting a wide range of frequencies that are near the key frequency.  Applying EQ to satisfaction is to determine the central frequency to be affected, the size of the Q and the shape of the curve and the amount of gain that is being cut or boosted.

Shelf EQ curve

Here is a shelf curve that sort of looks like – yes – a shelf.  Different EQ makers apply this differently and this one makes a slight cut prior to the boost.  By the way these are pretty extreme boosts being made in these examples to more clearly show what is being discussed.  Often EQ will be applied at much lower boosts or cuts and at several different frequencies.  The idea with EQ is generally to do as little as possible to affect the desired change.  You can easily mangle the recorded audio to something unacceptable.

Low Pass and High Pass filters

This picture shows a different type of EQ – the curve at the left is called a “High pass” filter and the curve at the right is called a “Low pass” filter.  These filters will remove all of the frequencies at the cut off frequency.  So, in this example, the high pass filter removes all frequencies below 100 hertz and the low pass filter removes all frequencies above 10,000 hertz.  These are very useful filters for removing unwanted elements of recordings.

These “pass filters” are powerful tools for affecting the recorded audio being processed.  Here are a few examples that might shed light on their particular usage.  Let’s say that your boom man has trouble holding the pole and his fingers are creating small “boom” sounds during the recording.  Often these noises are very low in the frequency range and are difficult to hear without a sub-woofer.  A high pass filter may remove all of the noises without affecting the quality of the recording.  Or perhaps the tracks sound a bit “murky” so a slight presence boost at 2.5K or 3.5K may help “lift” the voice and a small cut at 300 – 400 may remove a bit of “boominess.”  If you look at the EQ that has a low and high pass filter applied you’ll see that it creates a “band” of frequencies that will pass through it.  The other name for this sort of setting is a “band-pass” EQ and these can useful in a number of ways.  Since band passes limit the frequency range of a recorded signal they are useful for many things. Many devices such a telephones have a “limited band-width” so you can mimic this bandwidth with a band pass filter.

Notch at 1K

Let’s say you hear a steady noise in your recording that is present in the upper frequencies.  You may want to try a “notch filter” which can notch out the offending frequency.  Here several bands are tied together to really define the notch.  The idea here is to carve out only the offending frequency and try not to disturb anything else around it.  As you can see a graphical EQ is a very handy way of visualizing your sound.  Mix engineers will often “sweep” the notch along that horizontal range of frequencies until the frequency range to reduce or add is pinpointed.  Notches can be very useful in eliminating any type of steady state noise.  Steady is the key idea because if the noise or sound oscillates to other frequencies then the notch is no longer relevant since it is specific to only a narrow range of frequency.

EQ is an amazing tool with many useful applications.  However it is not a miracle device and it is most certainly not a noise reduction device.  It can indeed reduce noise but it is less successful at that than a dedicated noise reduction device is.  There are “broad band” noises such as air conditioners that cross many frequencies at one time.  They usually can not be notched or pass filtered out.  They will require some different processing, but if you need simple boosts or cuts or if you have tones that need to be minimized or emphasized in your recordings that are steady state, EQ will be the right tool to use.

This is merely a quick explanation of this wonderful, misunderstood and useful tool.  Experiment with EQ and learn how each of the controls affect the frequencies.  Learn how cutting and boosting achieves different effects and how specific frequencies affect specific sources.  Listen to the world at large and imagine if you had to use EQ to recreate the sounds you hear.  Walk by a stone building with music playing inside, loud but boomy and distant, what EQ curves might be applied to a standard music track to achieve a similar sound?  Listen to the world around you. This in time will guide you on how to use EQ to mimic the sounds in and of everyday life.  And then use those ideas to create the sounds you hear from this world – or others. Comment with thoughts, ideas or questions at will.

Simply put an OMF file is a digital container of all the audio files, edits, crossfades, pans and volume automation from your non-linear video editing platform.  It is a mighty handy tool compared to the old way of doing things. 

Here is a screenshot from Final Cut Pro.  You can see that there are eight tracks of audio, the top four of which are muted.

There is volume automation, panning information and a general temp mix in this edit timeline.  When we export the OMF from this timeline it will include tracks 5 – 8 only.  The OMF sees those muted tracks and leaves them out of the final export.  Most sound editors will want it all.  So I’d say unmute before the OMF creation.

Also a small FYI for those of you still using Final Cut 5 and below, the OMF is not a full spec OMF file.  It will not include volume automation, which if it’s feature length can create whole lot of extra work.  Not that you won’t re-mix from the ground up which is usually the case, but the temp mix can be a real time-saver for long projects.

I’ve also included a screenshot of the actual export of the OMF from the Final Cut Program.  Nothing fancy just a simple pull-down under File/Export – you can see – Audio to OMF.

You’ll get another dialog box after that which will give you a few options.  One is the handle length or the amount of audio that will be included on either side of any cut.  Handles are very important and contain loads of valuable information for a sound editor.  I generally ask for handles to be at lease five seconds if possible.  The default in FCP is 30 frames or one second.  Another option is to include volume automation and I would also add that functionality as well.  You can also choose to include crossfades which can be re-created by ProTools or the program that will be importing the OMF if they are not included.  There was a bug a while back in OMF exports that was related to crossfades.  This is no longer an issue.

What has just been detailed here is merely the mechanics of creating the OMF file.  As you can see it is a pretty simple and straightforward process.  Avid, FCP and other leading non-linear video editors offer some sort of OMF functionality and exporting them are all about the same process.  Make sure to mark an in and an out point create the accompanying movie file as well as the OMF from these same stop and start points.

Now that we have detailed the process of the OMF export what should be on the timeline in your non-linear video editor?  In my humble opinion, in a world of “less is more”, for audio post I would say that “more is more”.  If you have alt takes of lines, include them.  If you have roomtones include them.  Please.  Pretty please.

In fact I’m going to stop there.  Roomtones are a key component in audio post.  Period.  Notice the use of the word – key.  Not optional, not “if I can get to it”, not anything other than – key.  Not having roomtone is like writing without an eraser, a delete key or white-out.  Whoever digitizes the original camera tapes or dats will surely come across them.  Digitize them and stick them in a folder to give the sound editor or better yet as I advised cut them into your timeline and export them with the OMF.

I often ask the production recordist why they did not include roomtones and am generally told that they did indeed record them.  But somehow they never found their way to audio post.  So what happens to them?  They get lost in the shuffle with the mistaken assumption that they are not all that important.

In general picture editing gets a bit of time to complete their process.  Sometimes months and sometimes a year will be spent creating the final locked picture edit.  At the end of that they want the audio edited, mixed and output pronto.  So the best picture editors assemble their audio in a meaningful way to make the audio editors task simpler.  One thing that must be remembered is that all of that audio will be picked through, sorted, rearranged and cut to different tracks by the sound editor since it is their’s and the mixer’s job is to create a set of mix stems.  The editor had to create only one stem – a stereo temp mix.  And because of that many picture editors get lazy and just have their audio fall any where there is is room on an audio track.  This is fine for their temp mix but will not do to create a proper mix.  If Sound effects and music and dialog are all jumbled in the timeline – they will also be jumbled in the OMF.

Who cares?  “The audio guy will sort it all out ….”  The person who will care is the person who foots the bill.  Why?  Because they are going to be paying good money for studio time and an experienced sound professional to do basic housecleaning on the OMF.  It may sound minor but audio post deliveries are always tight and getting tighter and to waste a whole lot of time on things that have nothing to do with sound design and mixing is also a waste of the Producer’s money.  If you have a feature length project where the audio tracks were assembled willy-nilly it will take considerable time to sort out.    I have received OMF’s when opened reveal that the boom track and the lav track swap from take to take.  My job is to find “the best” sound and make that sound better.  If the boom sounds best then that means I have to audition and sort every single sound bite to determine whether it is the boom or the lav.  There may be thousands of these audio files in the timeline.  If the editor has diligently always put the boom on one track and the lav on another then he has cut my prep time considerably and I can concentrate on the task of making the movie sound even better.  Feel free to comment with questions since this is a huge topic that I’ve barely touched on.