Capturing audio in the field
Jul 1, 2003 12:00 PM, By Chriss Scherer, editor
Recording audio easily in the field combines a careful balance of several elements, including audio quality, recording format and equipment load. Thanks to the continuing miniaturization of electronics and mechanical devices, a great deal of recording power, quality and reliability is available in some highly compact devices.
The uses for portable recording vary widely, but the most frequent application is for gathering news, interviews or actualities. Because of the fast-paced nature of these events, recorders with minimal or easy-to-use controls and features allow recordings to be made quickly and without errors. Many options are available in portable recorders. The most basic models may have an internal mic or mic connector. Some have line-level inputs. Additional features added to the basic package include a built-in speaker, various selections for the recording speed or format, multiple inputs, stereo or multiple tracks, multiple power options or extended battery-time options, editing and transmission capability. As more features are added, the retail price naturally increases. The operational complexity may also increase.
When choosing a model, tailor the features to the application. A reporter on a daily news beat may only need basic recording with a built-in mic and maybe a line-level input for an audio pool feed. He will likely return to the studio after each element, so the editing and transmission features are unnecessary and may hinder easy operation.
Likewise, do not overlook the possibilities that the additional features may provide. If the extra items are out of the way and do not interfere with basic operation, you may find that these features are useful as new situations and needs arise.
Inside the extras
With a few basic differences, the audio quality of most recorders ranges from good to outstanding. When a poor recording is made, it can usually be attributed to an incorrect input level or an inferior-quality mic. Some recorders have internal mics, which may yield satisfactory results. They are convenient and simplify operation, but to eliminate background noise or get closer to the audio source, an external mic may be needed. A rugged dynamic mic can make a significant difference.
The external mic connection on a recorder can be a problem. Most connector choices are XLR or 3.5mm. Because of its size and locking capability, the XLR provides a more reliable connection, and it is less prone to being broken. The drawback is that an XLR connector is substantially larger. This is a limitation in the quest to design more-compact recording devices, but in most cases, an XLR connector will probably be the preferred choice.
Once the audio is recorded, it will most likely need to be transferred to another system. Removable media makes this easy in the studio. For digital formats, it may be quicker to transfer the file directly from the field unit through a direct connection, such as a USB port. In cases where the reporter will not return to the studio, the ability to transfer files via telephone may offer a practical solution. Some recorders offer direct POTS or ISDN connectivity to facilitate these transfers.
Choosing a format
Part of the decision process in choosing a portable recorder is to consider the media format. There are five basic formats in popular use: cassette, DAT, Minidisc, Optical (CD-R and DVD-R) and solid-state (PC Card and Compact Flash). Each format offers its own advantages and disadvantages. While all of them have proven to be practical and provide quality results for contribution material, certain aspects may make one more favorable over another.
When deciding on a format, consider the format's quality, the cost of the format media, reliability of the transport, availability of media and transferability of the media to other devices.
While cassette is still a popular choice, its analog format is an obvious disadvantage to digital formats. CD and DAT record linear digital audio, which yields the highest quality. Solid-state recorders typically offer several encoding formats, so the audio quality can vary by the choice made. Minidisc uses ATRAC audio encoding, which sounds good. In the end, all of them provide acceptable contribution-level audio.
When it comes to media cost, CD-R wins the race. When purchased in quantity, the price per piece can easily be well below one dollar. DVD-R is priced higher, but will see continued price reduction in time. Cassette and Minidisc are relatively inexpensive, with DAT prices being slightly more. Solid-state media has the highest cost, but it never wears out and can offer long recording times.
For reliability, nothing can beat a system with no moving parts. Solid-state recorders win in this arena. The tape formats require periodic cleaning. The optical formats also need clean lenses. Alignment and repair of the mechanical transports can also be a problem. The mechanical formats are also susceptible to problems from vibration.
It is unlikely that you will own a recorder and keep only one piece of recording media with it. It is always useful to have a spare. If a recorder sees frequent use on the road, the need to obtain backup media on short notice can arise.
I conducted my own unscientific research on this by visiting an electronics department store and a discount department store to evaluate the availability of various media formats. At both I found that CD-R and to a lesser extent DVD-R had the greatest representation in the displays, which was not surprising. Solid-state media was also popular at the electronics store, but was in the laptop and digital camera sections and not with the recording media. The next most popular was cassette. Minidisc had a small showing, while DAT was almost non-existent. Granted, any of these formats can be easily found through other outlets, but for a last-minute need, this is something to consider.
The ability to play the recording in another location can be convenient. Once a facility adopts a standard format, there is the option to play recordings in the studio. Even with this in mind, CD players are everywhere, and cassettes are common, making both convenient choices. Minidisc and DAT are somewhat rare outside the studio. Solid-state media will only be playable in the original recorder or perhaps on a PC.
Personal recorders for the consumer market are everywhere. While these devices offer long recording times, they usually do not provide professional features such as an external mic connection or the ability to download recorded data, and they may not be as rugged as professional designs. They may also use inferior coding algorithms.
The Resource Guide provides a sample of some current portable recorders that are available. For more ideas, see the Radio magazine Buyers Guide online.
The Denon DN-F20R uses Compact Flash media up to 192MB. The sampling rate is selectable between 24kHz or 48kHz, and the bit rate is variable from 16kb/s to 128kb/s (MPEG). The two memory card slots allow continuous recording. The unit supports MPEG 1, MPEG 2 and linear PCM (.WAV).
The Sonifex Courier records onto PC Card drives or memory cards up to 2GB and provides recording in MPEG Layer II, .BWF and .WAV formats. In addition, the unit offers POTS and ISDN connectivity with an internal phone book, a USB port for file transfer and a scrub wheel for on-board editing.
A sleek design makes the Maycom Handheld II easy to use for quick interviews. Using Compact Flash cards to record linear or MP2 files, the unit can also be placed into an accessory docking station to download audio files and provide additional I/O and battery recharging.
The Marantz PMD690 includes a built-in microphone, a built-in speaker and professional mic/line inputs and outputs. It records in stereo or mono to a PC Card or a Compact Flash memory card. Features include an automatic level control and a pre-record audio cache. Audio files can be saved as .WAV, .BWF or MP2.
The Nagra ARES-P records more than three hours of stereo with a 192MB PC Card. It records in G.722 or MPEG Layer II. Options include a plug-in mic. The ARES-P becomes the Digigram RCX220 with the addition of a USB port and a copy of Digigram's Xtrack editor.
The Orban Opticodec 7000 is a portable audio recorder that can edit and transmit via a built-in ISDN codec. It records in MPEG Layer II, Layer III, .BWF and .WAV to type III PC Cards. It features XLR inputs and outputs and a headphone jack. As many as 32 minutes of stereo audio can be recorded.
With XLR, RCA and S/PDIF I/O, the Marantz PMD650 Minidisc recorder features a 40 second audio buffer for shock absorption, two-second pre-record buf-fer, one-touch recording, variable mic attenuator, backlit LCD display, built-in mic and speaker, a remote control input and a headphone jack. SCMS copy control can be turned on or off.
The Tascam DA-P1 DAT recorder features 48kHz and 44.1kHz sampling rates, S/PDIF and RCA unbalanced analog I/O, balanced XLR mic/line inputs with 48V phantom power, a 20dB pad and limiter, a backlit LCD display for low-light conditions and a headphone jack. It will run for as long as two hours on a single charge.
The Pocketrec runs on a PocketPC PDA. The PDA can also run other applications. Audio files are created and stored within the unit or on solid-state memory cards. Record time is limited by the storage capacity. Files can be transferred through the PDA's connection methods. Basic audio editing can also be done.
The Sony TC-D5PROII cassette recorder is a lightweight stereo recorder and features a capstan-servo disc-drive system, external dc power input, balanced XLR mic inputs, VU metering with peak indicators, Dolby B noise reduction, a limiter and mic attenuator, a headphone jack and built-in speaker. A stereo line output is available on RCA jacks.
The HHB Portadisc MPD500 minidisc recorder has balanced XLR mic/line inputs, RCA phono line outputs, a headphone jack and S/PDIF digital I/O. A USB interface allows for real-time transfer of files to editing systems. Basic editing functions are also available on the unit itself. A memory buffer prevents errors from vibration and a six-second pre-record buffer adds additional confidence.
The Fostex PD-6 is a DVD-R recorder with a six-channel mixer that accepts mic-level (with 12V T-power and 48V phantom power) or line level signals. Each channel features adjustable input gain, a variable high-pass filter and limiter. AES-3 and S/PDIF I/O is also provided.
The Mayah Flashman records onto Compact Flash cards, which allow more than eight hours of recording on a 256MB card. The removable card can be read by standard PC card readers for file transfer. Its features include 32kHz/44.1kHz/48kHz sampling rates, S/PDIF I/O, XLR mic input, RS-232 data port and a stereo line output.
The Maycom Easycorder is a portable PC Card recorder that includes a graphical editor. A large illuminated screen and illuminated buttons, a mechanical and electrical lock during recording, a large gain control knob and presets for many operational settings add to the Easycorder's functionality. Storage is via the internal memory or via removable PC Cards.
The Sony PCM-M1 DAT recorder is the company's smallest and lightest DAT unit. It features selectable 48kHz/44.1kHz/32kHz sampling frequency selection, as long as 3.5 hours of continuous recording with supplied NiMH rechargeable batteries, selectable ID6 (SCMS copy protection), record margin indication, start ID level select, a back-lit LCD display, mic/line input, headphone output and line-level output.
The Marantz CDR300 features stereo XLR and �" mic/line inputs with 48V phantom power, S/PDIF inputs and outputs and an internal microphone and speaker. Record levels can be adjusted automatically or manually. You can also record your own CDs from audio sources such as CDs, LPs, cassettes or DAT.