Introduction

Field recording means different things to different people.  For some, it may be a primary or adjunct tool for work in disciplines such as cultural studies and anthropology (indigenous peoples, folkways, etc.).  Other recordists collect specific natural or manmade sounds for personal or professional work.  Some use audio captured in the field as a supplemental or integral part of multi- and mixed-media presentations.  And some musicians seek out sounds from outside the studio to blend into musical compositions -- either as components or as the "instruments" and "voices" of an entire composition.

Among these different users, the biggest points in common are that the activity takes place outside the studio, and that good portable equipment is essential.  Following are some observations and experiences.
 

Equipment:  Recorders

In the past, field recording equipment has followed other developments in electronics and audio-- the major difference being the need for portability.  And although you could, in theory, take a phonograph cutting machine into the field (and some did), the appearance of wire and tape recorders really opened up the field.  Reel-to-reel tape gave way (though not fully) to cassette recorders (more practical as noise reduction technology and better quality tape became available)...And then digital came onto the scene.  DAT (digital audio tape), Mini-DAT, MiniDisc are all examples of digital recording systems that use some kind of media the must be physically moved or rotated past a record or read head.

The most recent change has been the introduction of recorders that use solid state flash memory.  A recent flash recorder to hit the market is the Edirol R-09 (by Roland).  It uses SD/MMC flash memory cards up to 2GB.  That 2GB gives a recording capability of between 110 minutes (24 bit WAV file sampled at 48 kHz) to 1,993 minutes (83 hours of MP3 files at 128 kbps).  The R-09, lying down, has about the same footprint as one of the larger iPods, but is about twice the thickness.  Other recorders in the same price category ($500 and under) include the Marantz PMD660, the Edirol R-1, and the M-Audio MicroTrack 24/96.  All use Compact Flash (CF) cards and all but the MicroTrack are capable of providing standard 48-volt phantom power -- required for some condenser microphones.  Below are pictures of the Edirol R-09 -- the recorder I use.

Top:  Mic and line inputs, and built-in mics	Front:  Display, primary operating and menu controls, and mics	Back:  Recording controls
Bottom:  USB port, battery compartment, and SD/MMC card slot

In concept, these recorders are the audio equivalent of the point-and-shoot (P&S) digital camera, but with one distinct advantage -- described in the next section.

Equipment:  Microphones

All of the recorders mentioned above come with internal or included mini-microphones for recording in stereo.  These mics do a pretty good job for general recording.  In fact, even the most compressed (lowest quality) MP3 stereo recording of a meeting will be much better than what you get from the typical microcassette recorder.  But the characteristics and specifications of the built-in microphones are not always clearly described and may not be what you need for a particular task.  Additionally, by being attached to the recorder itself, built-in mics make some placement options impossible.

Here is where these new recorders offer an advantage:  Unlike their conceptual cousins -- the digital P&S camera -- the flash digital recorders let you select what is perhaps the most important component of the recording stream; the microphone.  The circuits and processes in the recorder are pretty much a known quantity.  But to achieve specific recording goals you have the option of using the best microphone you can afford -- or borrow.

Perhaps the most convenient external microphone to use for field recording is a single-point stereo microphone.  That means that at least two microphone heads are installed into/onto a single microphone body and feed audio to the recording device, usually through a single cable.  Prices range from around $50 to over $1,000.  To some extent you get what you pay for, although the most expensive microphones are usually specialist models. 

Most single-point microphones are condenser types.  These require a small current of electricity supplied by a small battery in the microphone, through phantom power from the recorder, or from an external power supply.  Condenser microphones are very sensitive, which helps in many recording situations.  But they are also more sensitive to wind/breath noise, and less expensive models are often poorly isolated from the mechanical noise that can occur when handling the microphone, or even when handling or moving the mic's cords.

I first tried a Nady CM-2S ($120 to $150).  One nice feature is the low frequency roll-off capability.  This allows you to reduce some of the low frequency sound.  It should be used judiciously, but in big spaces (like the underground Metro stations in DC) use of that feature either on the microphone or on the recorder (the R-09 has that option) keeps the "boominess" under control.  Unfortunately, the Nady microphone I ordered was defective.  The right channel recorded low and I had to add at least 4dB to the right track of the WAV files in the computer.  Getting the two channels matched is important for recordings if you want to present accurate spatial relationships within the sound field.  Further, the Nady had poor mechanical isolation, so handling noise on the mic body was a problem.  Even taps on the mic cable 4 feet away were transmitted to the microphone as thumps.  I returned it.

The next microphone, and my current primary mic, is the Sony ECM-MS957 ($180 to $300).  This microphone is a whole step above the Nady and uses a different technique for capturing sound.  Rather than using two (theoretically) matched mic capsules, the 957 has Mid/Side (MS) capsules for stereo panorama.  The Mid capsule picks up monophonic sound while the Side capsule picks up left/right difference sound.  Subtracting and adding the two capsule signals yield separate left and right channels, and also permits electronic adjustment of the pickup angle.  You can choose 90 degrees for a single sound source or 120 degrees to pick up many sources, ranged across the sound field. 

The rotating Mid capsule can be pointed through a range of 90 degrees.  This allows the microphone body to be vertically oriented, while the Mid capsule is oriented towards the horizon -- a configuration preferred by some recordists looking for a fuller sense of ambient sound.  Or the Mid capsule can be oriented towards the front of the microphone in the more conventional configuration.

The 957 comes with a very handy mic stand that allows the recordist to use the center column as a hand grip.  Although it is supplied with a conventional foam wind sock, I also decided to buy a Rycote Mini Windjammer for additional wind protection.  The 957 is somewhat sensitive to mechanical noise transmitted up the cable, and the supplied cable has a cloth covering that rubs and provides the noise -- I'll be trying one or two hand-assembled cords to see if that helps.

There is a "junior" version of the 957 -- the ECM-MS907 ($75 to $100).  This microphone is also a Mid/Side design with 90 and 120 degree selectable coverage.  The Mid element does not rotate.  It has a plastic body and some reviews note more susceptibility to mechanical noise.  But priced a little more than 1/3 the cost of the 957, this could be a good option for many.  It also might be considered when the recordist expects to encounter dodgy conditions (environmental or social).

In addition to the single-point stereo condenser microphones, field recordists have other choices in both condenser and dynamic forms:  Shotgun mics (mono and stereo), cardioid, unidirectional, omni directional, binaural, and parabolic.  For example, if you are assembling a more complex audio work, you might want to record general environmental sounds in mono, using an omni directional dynamic mic like the decades-old and nearly bullet-proof ElectroVoice 635A.  Other mono or stereo tracks could then be mixed with that background.
 

Equipment:  Headphones

Although you can monitor your recording by watching the VU meter or little bars on the recorder's display, that's not really telling you what is being recorded -- only that a bunch of sound is being collected.  (For you photographers, this would be like trying to take a picture with a digital camera using the histogram instead of the viewfinder.)  The goal is to isolate your hearing from the environment so that you hear only the sounds that the microphone and recorder are picking up.  This is useful because you'll know whether or not you "got" what you were trying to get, and also what other sounds you managed to pick up along the way.

Here are some approaches:

• Full Enclosure Isolation -- These are the classic big headphones that completely surround your ear and seal up against the sides of your head.  But just because they surround your ear, don't assume that they isolate.  Be prepared to spend some money (The Sennheiser HD 280 Pro and Sony MDR-7506 are good headphones to take a look at, for around $100 street price) and you'll need to try them on in a noisy environment.  The down side is that they are bulky, and you'll stand out in a crowd.  But they are easy to put on and take off.
• Over-Ear and On-Ear Noise Canceling -- Noise canceling headphones work by sampling the ambient noise and providing a 180-degree out-of-phase sound into the earpieces.  Visualize this as a sound wave from the outside encountering a matched sound wave coming the other direction.  They cancel each other out.  The problem is that these systems generate a certain amount of their own noise, so in over-ear types, there may be little real advantage over full enclosure isolation headphones.  On-ear noise canceling headphones may be an workable compromise between size and convenience, but they may not be effective enough in some sound environments.
• In-Ear Isolation -- These look like the earbuds people wear while listening to their iPods and MP3 players.  The difference is that are designed from the outset to seal the ear canal by means of foam or silicone sleeves, usually available in three sizes for best fit.  One of the first of these to achieve wide popularity are the Shure E2c earphones ($110).  There are three other models in the E-series ranging from $200 to $550.  I use the E2c earphones and they are very nice.  They allow you to be a little more discreet when you are out and about recording.  The problem is that taking them off and putting them on is a multi-step process, so they are best when you can stay hooked up to your recording rig

You can be sure that the light weight on-ear headphones and non-isolating in-ear phones will NOT be effective for field recording...There is just too much sound leakage.

Sennheisser HD-280 Pro

Sony MDR-7506

Shure E2c w/silicone sleeves

Software

One of the main advantages of digital recording is the ability to transfer files with no loss of data (the quality of the audio) and to be able to manipulate the audio files on a standard computer.  That can be a Windows machine or a Mac, desktop or laptop.  Granted, the speakers on your typical laptop leave a lot to be desired, but you are covered because you already have a good pair of earphones (see section above).

You may want to consider two different types of software:

• For editing and adjusting the stereo audio from the recorder I use Sound Forge 8.0.  There is also Sound Forge Audio Studio -- a trimmed down version.  Both of these are downloadable as trials, so you can see which you prefer.  I use the big version on my desktop machine, and the smaller version on my laptop.  In the shareware world, GoldWave 5.14 has been around for years and is also well worth a try.  You may want to make sure that the software will let you edit the "properties" of your audio files.  That way you can keep good notes on the technical details of you recordings.

• For developing productions, you'll need to step up to a program that allows you to blend multiple tracks of audio and/or video.  Sound Forge's high end product is Vegas 6, which will support you in editing and assembling DV or HDV projects from concept to DVD.  Those with more limited ambitions might find that one of the Vegas Movie Studio+DVD products may be sufficient.  Similar to the straight audio product, GoldWave has their MultiQuence multitrack mixer available.

Beyond those quick suggestions there are dozens of programs available for Windows and Mac that do some or all of whatever you might need for a project.
 

Audio Samples and a Project

Here are some early recording samples using the Edirol R-09 and the Nady mic, and a link to a multimedia project that used the R-09 and a Sony ECM-MS957 microphone:

• Sample 1 -- At the Courthouse Metro Station in Arlington, VA, between trains.  Just before the announcement starts, listen to some footsteps on the left and then they'll clarify as the wheels of a light stroller moves from left to right.  (You'll need to have the volume up fairly high.)

• Sample 2 -- The arrival and departure of two Metro trains at Courthouse Metro Station.  The first train is inbound to DC and comes from the right.  A little later an outbound train comes in from the left - behind the microphone.  The inbound train holds for a little while, and then both trains leave at about the same time.  In that case you loose some directionality since pretty much the same audio events are happening in both directions.  (The kid you hear at the beginning of this sample is the one who just went by in the stroller on the first sample.)

• Project 1 -- This will link you to a multimedia project I completed in August, 2006.  The Edirol R-09 was used for the field recording.  There is a complete description of the project off that link.