Radio College | Reading Room: Articles

Field Recording Equipment

by Flawn Williams

Flawn Williams has been a production engineer and trainer for NPR since the late 70's. His credits include Radio Expeditions for NPR/National Geographic, teaching with NPR's Next Generation Radio workshops, and stints as Technical Director of "All Things Considered" and "Performance Today". He also freelances on music and documentary projects, consults with independents on digital audio production, and teaches harmony singing.

(This article reprinted courtesy of NPR's Engineering Update Online.)

fwilliams@npr.org
radio@flawn.org

Radio news at its best brings the listener information and emotion from around the world. A reporter out in the field is charged with gathering moments to deliver to listeners. The quality of the recording equipment, and how it is used and treated, have a major influence on the intelligibility and aesthetic impact of those moments.

The last few years have seen several new types of recording gear suitable for use by radio reporters. The analog cassette used to be the dominant format; now MiniDisc, DAT, and some newer digital alternatives are being used.

Before going into the details of each format, here's a rundown of basic common features shared by many recorders that reporters use. Some recorders will have slightly different interpretations of these features: consult the manual for your recorder for more detailed information.

Basics of Portable Recorders

Battery power

Unless your reporting work always takes places within reach of a wall power outlet, your recorder needs to run off batteries. These may be single use disposables, or rechargeable regular batteries, or special dedicated rechargeable packs. Many recorders offer a display of remaining battery power, so you'll know when new batteries or a recharge will be needed.

Record Button

This button (sometimes used in combination with the Play button) starts recording sound.

Play button

Starts the machine playing back previously recorded information.

Stop Button

Pushing this button stops any previously selected operation.

Fast Forward

Moves forward in time at high speed, with no sound heard. Usually engaged from Stop mode.

Cue

Moves forward in time at high speed, with sound heard. Usually engaged by holding the Fast Forward button down while in Play mode.

Rewind

Moves backward in time at high speed, with no sound heard. Usually engaged from Stop mode.

Review

Moves backward in time at high speed, with sound heard. Usually engaged by holding the Rewind button down while in Play mode.

Pause

Temporarily stops record or play, but keeps unit ready to resume.

Automatic Level Control (ALC)

A circuit which senses the strength of the audio signal coming into the recorder from your microphone or other source, and adjusts the recording volume automatically for optimal recording. Also known on some brands as automatic gain control (AGC) or automatic volume control (AVC). Many recorders offer only automatic control; others let you choose automatic or manual control. ALC can reduce loud signals, and can also raise weak signals, to maintain a good average recording level.

Manual record volume control

A knob or slider which lets you set the sensitivity of the recorder to compensate for the strength of the audio signal coming into the recorder. Its operation may be defeated on some models by selecting automatic level control (ALC).

Manual with Limiter

A variant of manual record level setting, which lets you set the overall sensitivity manually but includes a circuit that will momentarily reduce the level setting automatically when loud peaks that would cause distortion are detected. Usually defeatable by using a Limiter On/Off switch. Unlike ALC, a limiter only works by reducing peaks, not by raising weak signals.

Headphone jack

A receptacle for connecting a set of earphones. May be either a mono or stereo type, depending on the recorder. May also be labelled Monitor. Volume for this jack is typically controlled by the Playback volume control.

Playback speaker

A small loudspeaker built into the recorder for monitoring playback of recorded sound. On a few models, may also be used to listen during recording. Typically not high fidelity, but adequate intelligibility for locating particular sections of the recording.

Playback volume

Controls the loudness of sound being played back after recording, heard through a built-in speaker or through headphones. May also control loudness in headphones during recording. In either case, does not affect the recording level.

Playback tone

Controls the tone quality of the sound being played back through the speaker or headphones after recording. Turning this control up increases the crispness or sharpness of the sound; turning it down may make the sound duller or more mellow.

Line Out jack

A fixed-level audio output jack, typically not affected by the Playback volume control. Used to connect directly to other audio gear.

Mike input jack

Allows attachment of an external microphone to the recorder. For broadcast-quality recordings this is necessary; though some recorders include built-in microphones, their audio quality is typically inferior, and they pick up a lot of directly conducted noise from the recorder's motor. You'll need a cable with the proper connectors to match the mike input jack and your microphone to make the connection.

Line input jack

Allows attachment of connections from other audio gear being sent at "line level", which is electrically stronger (much higher level) than typical microphone signals. For recorders lacking a line input jack, you'll need an attenuating patch cord to weaken the line level signals before feeding them into the mike level input jack. On some models, the same jack can be used for mike or line level signals, using a "Mike/Line" switch or a built-in attenuator switch. Typical difference between mike level and line level is 30 to 50 deciBels (abbreviated as dB).

Tape Counter or Time Display

These displays can be helpful in logging and locating particular spots in the recording. Most cassette recorders have three-digit mechanical counters which measure revolutions of the feed spool or take-up spool, and are not accurate readings of elapsed time. More recent formats offer time displays of minutes and seconds, some using a resettable counter, others actually recording time data along with the audio and displaying that data on playback.

Auto shutoff

Many recorders will release the record function and stop when they reach the end of the tape. This can alert you that it's time to change the tape or flip it over and restart recording. Some DAT recorders go into rewind when they reach the end of the tape.

End-of-tape alarm

Some models offer a flashing light or a beeping in the headphone jack (not in the recorded audio) beginning a minute or two before tape runs out. This gives more warning than just an auto shutoff system.

Variable playback speed

Some models can change the speed they run at during playback. This can be useful for speeding up playback during scanning or logging functions. It can also save cassette recordings that were made at incorrect speed due to failing batteries.

Off tape monitoring

Some models have separate heads and electronics for record and playback. These can let you listen to a playback signal coming back off the tape during recording. This is also referred to as confidence head monitoring, since hearing some of the tape playback during recording lets you be confident that something is really making it onto the tape!

Record inhibit tab

On analog cassettes, there are small plastic tabs on the rear spine of the cassette which can be broken out. When these are removed, a cassette deck will not go into record mode while that tape is loaded. If you later change your mind, placing some adhesive tape over the holes where the tabs used to be can allow recording again.

DAT cassettes, MiniDiscs, and many other formats have sliding tabs built into the casing which serve a similar purpose. And disc-based and solid-state formats have the ability to lock particular files to prevent recording.

None of these record inhibit systems protect your recordings from accidental erasure by outside magnetic fields from loudspeakers, motors, etc. They only prevent the recorder from re-recording over your protected tapings.

Search to ID marker

Most digital recorders incorporate some form of marker signals recorded along with the audio. These may be simple ID marks, or they may have unique numbers attached to them. For some types of reporting this can make location of elements much quicker and more dependable.

Now, on to the details of different formats!

Analog Cassette Recorders

Analog cassettes are still being used by many reporters. They offer dependable operation and the familiarity of a format that's also common in your car and home sound systems. Cassettes have been in use by reporters since the mid-Sixties, and have come a long way in quality in that time.

Cassette tape basics

Types of cassette tapes

The earliest analog cassettes used ferric oxide tape, now referred to as "normal" or "Type I" tape. Many portable recorders used by reporters are designed to record only on Type I tape. If you can't find any switch or indicator on your recorder showing what kind of tape it's supposed to use, assume that Type I will work in all machines.

Many models can also use Type II cassettes, referred to as "chrome" or "high bias" tapes. Some recorders can recognize automatically whether an inserted tape is Type I or II, by detecting an indentation on the rear spine of the cassette next to the record inhibit tab. On other recorders you have to use a manual switch to set the recorder for proper operation with the tape type you're using.

The highest quality cassette tape is called metal or Type IV (the short-lived Type III, or ferrichrome, was a blend of ferric and chrome oxides). Metal cassettes require much more bias current for proper recording, so using metal cassettes can reduce battery life in portable recorders by a third or more. But their sound quality, when used with a recorder that can drive them properly, is excellent.

Within each type category of tape, the various manufacturers will have a range of quality. In general, the more expensive lines offer higher output level, less tape hiss, and better shells.

Shell construction

You can put great quality tape in a cheap shell, and the results will sound terrible. This can be a problem with the tapes you see being advertised in the back of audio magazines. Sellers trumpet the fact that they're using TDK SA or BASF chrome tape, but don't tell you what kind of shell it's been loaded into.

A good shell provides environmental protection for the tape, keeps it packed smoothly, provides a low-friction path for the tape to move along during record and playback, and doesn't warp in high temperature conditions. Shells made to closer tolerances for all these factors cost more money, but they'll yield better sound quality and longer life for the cassette.

Many cassette shells are glued together or "welded" with ultrasonic vibrations. But the better shells are assembled with five screws, one at each corner and one in the middle. If an irreplaceable recording should ever suffer a jam or snap the tape, you'll discover another advantage of screwed shells: you can disassemble the cassette, remove the tape, and splice or straighten it. Then you can reassemble the tape in the same cassette, or (if a damaged original shell was part of the problem) transplant the valuable tape to a "donor shell" from another cassette. In contrast, opening up a welded or glued shell requires prying and cracking which can further damage that valuable tape you're trying to resurrect!

For best results with cassettes, follow these guidelines:

Don't use C90 or longer length cassettes. The tape in all cassettes up through C60's (30 minutes per side, one hour total) is the standard thickness tape. The tape in C90's, C120's, and the deservedly rare C180 cassettes is thinner, and more vulnerable to damage, print-through, and other problems.

Don't use the first and last 30 seconds of the cassette, as those areas have higher dropout rates than the rest of the tape.

Use the best type of tape that your recorder is designed to use, and within that type use the best quality of tape that you can afford. Your recordings will be audibly better, and if you reuse cassettes several times the cost difference for good tape is negligible.

If you reuse tapes for several recordings, bulk erase the cassettes to get rid of old recordings before making the new ones. This is particularly important if the cassette may get used in several different recorders: unless their heads are aligned exactly the same, one recorder may not be able to completely erase an existing recording made with another recorder.

If you intend to save a recording, break out the record inhibit tabs on the rear spine of the cassette. This will protect the cassette against accidental erasure.

Clean the tape path of your cassette deck regularly with cotton swabs and denatured alcohol, as even invisible particles of dirt and oxide can compromise the tape-to-head contact and impair the recording or playback quality.

If your portable cassette recorder offers a noise reduction system, such as Dolby B, C, or S, or dbx, experiment with using it. When these systems work properly they can dramatically reduce tape hiss noise. But remember that they are closed-loop systems: in order to do their job right, the same system must be used during record and playback. And they work best when you're playing back your tape on the same machine that it was recorded on. If you use a different machine for playback, be aware that small differences in head alignment, or even differences in the circuit implementation for a particular kind of noise reduction system, can lead to serious degradation of sound quality. Listen carefully to the results, and let your ears be the judge.

Mono or stereo?

Portable cassette recorders come in both mono and stereo formats. If your reporting work is going into a mono program, you might presume that you'd need a mono recorder. But a stereo recorder can offer some advantages even for mono recordings:

Noise reduction systems, which can reduce the sound of tape hiss, are available only on stereo cassette recorders
The ability to use chrome or metal bias cassettes may not be offered by all mono recorders
A stereo recorder may offer options for manual recording level control, or manual with peak limiter, whereas many mono recorders allow only automatic level control (ALC). Conversely, few stereo recorders have ALC, so if you want that you may need to use a mono recorder.
A stereo recorder can let you record using two separate mikes, not necessarily placed for stereo effect, but in a split track arrangement to get close perspectives of two different voices, or two different perspectives of the same event. They don't have to get mixed together in the field; you can decide later on whether to use just one track or the other, or perhaps a blend of both, in your final program. See the discussion of split track recordings in the Techniques section.

Cassette recorders commonly used by reporters

This section is not intended as a particular endorsement by NPR of individual items of equipment. It's just a listing of several recorders that have produced a lot of good public radio from NPR and member station reporters! We welcome nominations from public radio reporters for additions to this list.

Marantz makes a small fleet of portable models. Their basic mono recorder is called the PMD 201. It has a basic footprint of about half a square foot, so it's larger than the Walkperson wannabe's, but it's a good basic reporter machine. It has mike and line inputs. The same machine, with an extra playback head to give you the confidence of off-tape monitoring, is called the PMD 221. And a later variant of that machine, with a balanced mike input with XLR connector in addition to the mini jack mike input, is called the PMD 222. (Early production runs of the PMD 222 had severe sound quality problems with the circuit for that XLR mike input, so if you're buying a PMD 222 compare the recording quality through the XLR jack with the mini mike input jack.)

The same basic chassis is also used for two Marantz portable stereo decks, which offer noise reduction but no option for Automatic Level Control. The PMD 420 is the two-head version, and the PMD 430 adds the extra third head for off-tape monitoring.

Sony's venerable TC-D5 variants have been a good portable option for many years. First there was the TC-D5, a portable stereo recorder with Dolby noise reduction, an input limiter, and quarter-inch mike input jacks. The TC-D5M added support for metal tapes. Then the TC-D5 Pro changed the mike input jacks to XLR...but curiously made them male jacks instead of female. Finally the TC-D5 Pro II managed to squeeze in the correct female XLR input jacks.

Sony also made several smaller stereo recorders known as recording Walkman decks. The TC-D6 (also known as a WM-D6) and the WM-D3 have excellent recording quality but suffer from some ruggedness problems due to their stereo mini input and output jacks.

Mono Sony recorders used for reporting have included the TC-142, the TCM5000, and the TCM5000EV. The "EV" machine added a "Vox" voice-activated recording feature that, while useful for transcription use, is not good for broadcast work, since it often chops off the top of the first word when starting to record. Worse, the audio quality of the "EV" is degraded by the sensing circuit for the "Vox" feature even when "Vox" is switched off.

Enter the Contenders: Newer Digital Formats

With the exception of a few high-budget reel-to-reel recorders, cassettes ruled the roost as reporter machines for many years. But starting in the late Eighties, some new types of portable recorders began appearing. Almost all of these make use of some form of digital storage, as opposed to the analog recording of cassettes and open reels.

Digital audio solves a lot of the problems inherent in analog recordings, but has brought in a few kinks of its own. So there are both advantages and disadvantages to reckon with if you're considering one of the newer recorders:

Time Base Stability: variations in the running speed of analog recorders show up as unstable pitch, wow, and flutter. Digital formats eliminate this problem.

Signal To Noise Ratio: all but the best analog cassettes have audible tape hiss, though this can be minimized by using good tape, noise reduction, and careful maintenance of recorders. Digital recording formats have much less audible background noise.

Frequency Response: digital recorders offer a wider frequency response than analog cassettes, though for voice recording this may be overkill. Most digital formats have response from 5 Hertz to 20 kiloHertz; FM radio won't carry anything over 15 kiloHertz, and cassettes are hard put to deliver above 10 kHz unless maintained impeccably.

Uninterrupted Recording Time: if you're tired of flipping a cassette every 30 minutes, consider that some digital formats can run several hours without interruption. If all you do are short interviews, though, having so much recording time on one little piece of media may be more confusing than convenient.

Cost Of Recorder: the few remaining analog cassette machines being sold cost several hundred dollars, and DAT recorders are the same. But some of the small-format MiniDisc recorders can be had for substantially less.

Cost Of Media: analog cassettes are still cheaper, but again the gap isn't nearly as bad as it used to be. A good quality C60 cassette will cost you a couple of dollars; a two-hour DAT can be had for as little as two to four dollars. If you get a DAT recorder that runs in the LP (Long Play) mode, it can record for four hours on that $4 tape, with quality still much better than analog cassette.

Common Availability Of Media: as of this writing, the analog cassette still rules in this contest. Cassettes are available worldwide, in almost any "civilized" location, in drugstores and corner kiosks. Digital media are far more obscure, so you'll need to be more careful about stocking up in advance, and taking along more tapes/discs than you could possibly use!

Common Availability Of Batteries: most digital recorders can run on commonly available AA batteries, but some run on either dedicated rechargeable batteries or outboard battery packs. Most also consume more power per hour than analog recorders. All analog cassette recorders mentioned here, in contrast, run on commonly available C, D, or AA cells. Most DATs consume more power per hour than analog recorders, though the small MiniDiscs have gotten more power-efficient with each generation of models.

Recording While In Motion: cassette recorders, and even those pricey analog open reel portables, suffer from severe variations in tape speed when the recorder is being carried by a reporter who is walking, running, riding a bike, or bouncing along in a 4-by-4 vehicle. In the digital camp, there's a split: DAT recorders are extremely stable while recording in motion, for example, but MiniDiscs are even worse than analogs in this regard.

Ruggedness: it's hard to generalize about this, as there's a great variability from model to model within each group. Digital recorders that use tapes or discs are more complicated mechanisms than analog cassette recorders, and hence may be more vulnerable to physical damage. But several years of experience show that good results can be had with either variety.

Environmental Tolerances: DAT recorders can have temporary problems from moisture condensation if they're taken from a cold dry environment (outside during winter) to a warmer, more humid setting (indoors). This can make the recorder refuse to record or play back until it warms up. But ALL media, analog and digital, are susceptible to permanent damage if exposed to extreme heat such as being left in direct sunlight or stored inside a car in summer. And analog tapes can start shedding their oxide particles if exposed to extreme cold.

Repairability Of Media: wrinkles and creases in recording tape will cause dropouts in both analog and digital machines. In the analog, the dropout may be just a momentary dip in volume or high frequency response; in the digital, media damage will usually result in more severe distortion of the sound, or a momentary total loss of audio. If an analog tape breaks, it may be possible to open the cassette and splice the tape, with little loss of material; this approach is also possible with DATs, but it's likely to have a great loss of audio, and if the splice isn't done cleanly you could compromise or even damage the deck that the tape is played back in.

Indexing And Location Features: the various digital formats are far more capable in this regard than analog cassettes. A portable cassette deck probably has just a mechanical three-digit counter for guesstimating locations, and no way of locating a particular spot on the tape automatically. In contrast, most digital recorders embed timing information called Absolute Time along with the audio data, so it's much easier to return to a particular location. There are also position markers called Track ID's or Start ID's, and numbered ID's called Program Numbers, plus features for locating the end of a recording. And some digital recorders add Date-and-Time as well, which is a great reference for reporters!

Generation Loss In Audio Copying: what happens to your field audio after it's recorded? Will you transfer it to open reel tape, or cart, or into a workstation for editing and mixing? Each time you copy or transfer from one format to another in the analog realm, you lose a bit of quality. But if you can make a direct digital link, the copy can be essentially loss-free. A caveat is in order here: some digital recorders and computer systems use data reduction algorithms to cut down on the amount of data before storage. For the first few generations, these systems can sound good. But after several generations of transfer these data-reduced digital signals can start to suffer from chirps, background whines, and other audible artifacts that can be even more noxious than analog generation loss.

Compatibility With Studio/Production Equipment: the best way to avoid a generation loss from your field recordings to studio production, is to be able to use the same format in the field and in the studio. Analog open reel recorders offer this advantage: you can cut and mix the original field tapes. On the digital side, MiniDisc offers a similar advantage: there are studio editing and replay systems available which can play back from the same disc you recorded originally in the field, with tight cueing capability. And some newer solid-state memory recorders let you pop the memory chip out of the recorder and plug it directly into the computer for loss-free transfers.

Now, having mapped out some of the general distinctions between analog and digital characteristics, let's examine some basics for each of the currently available digital formats.

Digital Audio Tape (DAT) Recorders

The first portable DATs arrived in 1988, and their use peaked in the 90s. Since then their share of the market has been lost to newer formats, and only a few models are still being sold. The DAT format uses linear pulse code modulation (PCM) recording, and does not use any form of data reduction. The standard DAT records at 48 kHz sampling rate with a resolution of 16 bits for a theoretical dynamic range of 96 dB. Some recorders can also do 44.1 kHz, the CD standard sampling rate. Frequency response is rated as roughly 5 Hz-20 kHz.

The mechanism looks like a shrunken VCR, and that's essentially what DAT is: tape is pulled out of a sealed cassette and moved at slow speed past a rotating head drum; the heads on the drum write the data as a series of diagonal magnetic stripes on the tape.

Like VCR's, DATs can record for a long time on a small tape. The longest standard-thickness tapes run just over two hours, with no need to flip the tape midway through. Some DAT decks have a Long Play (LP) feature, which slows the tape speed down to double the recording time on a given tape at a lower sampling rate (32 kHz) and resolution (companded 12 bit instead of linear 16 bit). Frequency response at this lower sampling rate tops out at about 15 kHz, the same upper limit as FM radio.

All portable DAT decks are stereo, and by the rules of the format they record both channels at once: you can't go back and record the right channel after the left, for instance. But they're certainly useable for mono work, too.

As a group they're pretty power-hungry. Many of them use rechargeable batteries which will only run the deck for one to two hours before recharging or swapping out. Some later small models, such as the Sony TCD-D100 and PCM-M1, can run for a few hours on two AA alkaline disposable batteries. Most DAT recorders have some means of accepting DC power from an external source, so larger outboard batteries are the most practical powering option for portable DATs.

One great advantage of DAT over other formats is that it's relatively immune to motion problems. In the past I've lost several great recordings using a Nagra analog reel recorder or cassette deck because I was having to run while recording, or was in a moving vehicle on a bumpy road. DAT recorders handle these assignments in stride, so with them recording in motion is limited only by the shock mounting of your microphone and your own susceptibility to motion sickness!

DAT tapes, once recorded, are almost immune to accidental erasure. The tape is "high coercivity, high retentivity," which means you can set tapes near speakers, motors, and other sources of electromagnetic fields which might erase analog tapes. This can even be an annoyance, as it's almost impossible to "bulk erase" a DAT tape without using a massive eraser. Luckily, the DAT deck itself can overwrite old data nicely as it makes a new recording.

The DAT format is comparatively fragile and environmentally sensitive. It pays to be a bit more cautious with DATs when it comes to exposure to cold, rain, dusty wind, and direct sunlight or extreme heat. But with a little caution the recording results can be impressive.

Which DAT deck is best for reporter use?

There are plenty of factors to consider, but not plenty of models to choose from. Most manufacturers have stopped making portable DAT recorders, deeming them too costly and complicated for the small market. For many reporters the overriding factor is cost, and the winner in the "cheapest machine on the street" contest goes to Sony's TCD-D100, which can be had for $900.

But particularly for a machine that a reporter is going to bounce all over town, the small DAT recorders may not be dependable enough. If you do experience problems with your recorder and don't have a dedicated service department backing you up, you may wait weeks or even months for service from a consumer-oriented shop. A backup spare machine is highly advisable if you're going to rely on these Walkman-style models.

A more rugged alternative is the Tascam DA-P1, a larger deck which has XLR input jacks; it can also supply phantom power for condenser mikes. It can be found for $1300-1500. And beyond that are a few models being aimed mostly at the professional film sound market, which offer more features but at prices that approach or exceed five figures. For some entertaining and informative chat about the comparative attributes of various models of DAT recorders, you can join the DAT-Heads computer mailing list. To subscribe, send a message to dat-heads-request@fedney.near.net with unsubscribe on a line by itself. And for some specific information related to various portable DAT recorders, not sponsored by Sony, turn your Internet browser to Victor Yiu's personal page at: http://www.rockpark.com.

Choosing your DAT tape

As mentioned earlier, DAT tapes aren't widely available in malls and other "civilized" areas. So you need to carry with you more than what you'll need. Fortunately, they're small and light, and they hold a lot of audio.

All DAT tapes up to two hour lengths use the same thickness of tape, so there's no great difference in reliability. If you find it too confusing to have two hours of material on one little tape, you can buy shorter lengths, but the cost per minute of recording time is much cheaper with the longer lengths.

Audio DAT tapes are marked with numbers showing their recording time, so for instance a DT120 tape holds about two hours of audio at regular speed. At the Long Play speed offered by some recorders, you can put four hours of audio on a DT120 tape.

Any tape that is labelled as a DT180 or higher uses a thinner than standard base tape, which may not hold up as well in heavy use as the standard tapes. Some DAT decks seem to handle the thinner tapes gently enough for good results, but other decks don't do well with them.

DDS vs. DAT Tapes

Adding further confusion in the DAT labelling scheme is the fact that DAT technology has also been pressed into service for a computer data storage format called Digital Data Storage or DDS. DDS uses tape and shells that are the same dimensions as audio DAT tapes. But DDS tapes are identified by the length of their tape, rather than minutes of audio. A 60-meter DDS tape holds the same amount of tape as a DT120 two-hour audio DAT. A 90-meter DDS can hold three hours of audio but uses the thinner tape. And the DDS-2 data storage standard offers a still-thinner 120 meter tape which could hold four hours of audio.

Or can it?

Are the two tape types compatible? This topic has been the subject of much discussion and consternation. Sorting out the technical facts from the marketing hype is an ongoing nightmare. Some respected manufacturers insist that the two systems use different tape, and that using DDS tapes in DAT decks can cause damage to the recorder or the tape. Other, equally respected manufacturers say they use the same tape stock in both DAT and DDS products, and that no problems should result from using DDS tapes to record audio.

If you want to err on the side of caution, stick with the DAT tapes for audio. If you want to test DDS tapes for audio, a prudently cautious position would be to stick with the 60-meter tapes (two hours of audio) but avoid the thinner 90- and 120-meter varieties.

Why bother considering DDS tapes? The DDS standard, when it was introduced a few years after DAT, specified better error performance and stricter quality control than the original DAT specs. At first, DDS commanded a premium price. But the computer peripheral market is much larger and more competitive than the audio DAT market, so prices have fallen to the point where typical DDS 60 meter prices are now lower than DT120 DAT prices.

Even if you don't try the DDS tapes, you'll be benefitting somewhat from their existence. Those manufacturers who say that their DDS and DAT tapes are the same tape stock, explain that they've improved the quality of their DAT tape stock over the years to meet the stricter DDS specifications!

MiniDisc Recorders

Sony rolled out this format as an intended replacement for analog cassettes among music-loving consumers. Growth in that market has been sporadic, but along the way the format caught on with radio stations as a decent replacement for analog tape cartridges (carts). Now there are numerous manufacturers building MiniDisc recorders and players; Sony, Aiwa and Sharp have the best-known small ìconsumerî portable recorders, while HHB and Marantz have larger and pricier models with many features useful to reporters.

The biggest difference between MiniDisc and earlier recording formats is that it uses discs instead of tape to store data. This brings the huge advantage of random access playback and recording, similar to the way a hard drive or floppy drive works in a computer. Markers can be created to allow instant location to a particular piece of audio, and on some decks a rudimentary form of cut and paste editing can be done right on the MiniDisc.

The MiniDisc uses a data reduction system it calls ATRAC to fit more than an hour of stereo digital sound on a 2.5" disc. The psychoacoustic coding and data crunching of ATRAC reduce the data by a factor of five. How's the quality? For a single generation of recording and playback, it has been judged to be "CD quality" or even slightly better in some respects. But if the sound goes through several generations of data-reduced transfer and storage (which is increasingly possible in this era of data-reduced digital satellite transmissions, hard disk storage and editing systems, and studio-to-transmitter links), data-reduced original recordings are more susceptible to developing strange audible artifacts than their non-reduced cousins DAT and CD are.

Another potential problem for mobile recordists: most MiniDisc recorders may suffer disrupted data if the machine is jostled or placed on a vibrating surface during recording. The laser that writes the data to disc can be displaced from its position by sudden jolts. The format has a clever way of protecting against such disruptions during playback, by using a memory chip as a data buffer. But only the most expensive portables have any buffering of data during recording.

Try out any recorder before you buy, to see how it responds to being bumped during recording. And remember that it's most vulnerable to corruption if it's moved in the few seconds AFTER you stop recording. The recorder needs to write a new or revised Table of Contents (TOC) when recording stops. If jostling disrupts the writing of the TOC, the recorder may lose the ability to find and play ALL the audio on that disc!

Storage capacity for each disc is up to 80 minutes of stereo sound. Some portable models allow mono recording and playback as well as stereo. And unlike tape recorders, going to mono lets you double the amount of recording time available on each disc, up to 160 minutes (about 2.5 hours)! There may be some compatibility issues between this mono format and stereo studio decks. But in general, MiniDisc offers another advantage: if your station has invested in studio MiniDisc recorders and players, the discs you record in the field can be indexed and played directly in the studio, without the need for dubbing from the field medium.

The most recent small portable decks offer a choice of different data reduction algorithms, to give you the option of packing more and more recording time on a single disc at the expense of significantly reduced sound quality. These 2x and 4x settings are not recommended for broadcast work.

In addition to their mike and line inputs, most of the small portables have a digital input, which lets you record directly from the digital output of a computer or other source. This nod to the MP3 generation has revived what was a failing consumer market for MiniDiscs. Unfortunately, most of the portables lack a digital output, which would be of much greater use to reporters! The Marantz PMD650 and HHB Portadisc do have digital outputs, and the HHB also has a USB jack for file transfers to a computer.

Another variant of the MiniDisc format has been introduced by several manufacturers: a MiniDisc version of a four-track "Portastudio", like a higher quality version of the little cassette multitrackers that musicians use for demo and practice work. This could make an interesting personal production center if you regularly need to create radio pieces far from your home studio. Unfortunately it's not directly compatible with regular MiniDisc machines: it uses a computer-data MiniDisc format instead. Also, these multitrackers typically don't run on batteries, so they have to be plugged into wall power.

If you'd like more information on MiniDisc, check out the MiniDisc Page at www.minidisc.org.

Solid State Recorders

Many of the developments in audio equipment in recent years have exploited R&D done for laptop computers, digital cameras, etc. And as higher-capacity solid state memory devices become cheaper, their use in audio products is increasing. The plethora of hand-held solid state note-takers shows where the future lies: these little gadgets measure their recording time in minutes rather than hours, and their audio quality sounds like a bad phone line, but they are proof that sound can be stored and retrieved by a hand-held digital gadget without tape or disc.

The limiting factor here is capacity and cost. Memory cards, at this writing, are falling through the $1 per megabyte level. For reporters who need only a few hours of recording time before dumping to computer and reusing the memory cards, this can be a practical and cost-effective option, since storage space on an IDE computer hard drive is falling through the $2 per gigabyte level. That's a difference of 500 to 1! Recordable CDs can also be used to archive audio data files for under $1 per gigabyte.

Marantz's PMD-680 mono and PMD-690 stereo recorders use PC card memory or the PC-card-sized Micro hard drives for recording and storage. These recorders offer several different levels of data reduction, similar to MiniDisc, but they can also be set to record uncompressed full-quality audio like a DATÖif you can afford the big memory cards you'll need to capture that quality!

A more upscale implementation of this same concept is Nagra's ARES-P recorder. This device is actually a handheld recorder which uses PCMCIA memory cards. It can record data-reduced audio using MPEG2 compression, which offers performance similar to MiniDisc, or it can record uncompressed audio. A variant of this recorder, the RCX-220, adds a USB port for connection to a computer.

There is great potential for some nice little recorders based around small hard disc drives. The Apple iPod and other MP3 players show the potential for storing large amounts of sound on a 1.6-inch hard drive, and Archos' Jukebox portable MP3 recorder can record to an internal 20 GB drive, but so far the audio quality isn't up to good broadcast standards.

Direct to Computer Recording

Closer to mortal budgets, there are exciting developments in laptop and desktop computers' audio recording and playback capabilities. With a mike preamp and a laptop computer, you can record an interview directly to the computer's hard disk drive.

But there are still problems with this approach. The internal analog-to-digital and digital-to-analog converters built into these computers are far lower fidelity than the pricier add-on sound cards, even if the internals are described as "16 bit digital quality". Decent quality sound interfaces with direct digital inputs and outputs for laptop computers are still restricted to outboard devices that connect to the laptop through PC Card slots, the USB bus, or a Firewire connection.

And even when those problems get solved, the quality of your recording may be marred by the ambient noise of the computer itself! Modern laptops may have noisy internal fans to cool their ultrafast CPU chips, and that whirring hard drive sound can get pretty noticeable in a quiet interview. The real breakthrough for this style of recording will come with even larger capacity/lower cost solid state memory cards, and notebook computers that rely on such cards rather than disks for storage.

CD Recording in the Field

Given the low cost of recordable CD and CDRW media, and easy importing of CDs into computers, it would seem natural to exploit this format for field recording. Marantz and Superscope have created portable CD recorders with mike inputs and other useful features.

Unfortunately, the format is not meant for over-the-shoulder operation. It has a lot of problems with recording while in motion, as do the other disc-based formats mentioned above. These CD recorders are meant more for tabletop use such as taping a school board meeting or concert performance.

Helpful accessories for the recorder

No matter which type of recorder you decide to use, there are a range of accessories you'll need in order to cover a reporter's needs. Here are things you should not leave home without:

A Quality Microphone is so important that we've given it its own section.

Extra Media

Take twice as much as you think you'll need. Cassettes, DATs, MiniDiscs and memory cards are all pretty lightweight and compact. They're also more or less hard to find (or expensive!) out in the field, and besides, going looking for them at stores would waste valuable reporting time. And the day that you take only what you know you'll need, is the day that the first tape you unwrap in the field will be defective. Thus saith the gospel according to Murphy...

Extra Batteries

It's hard to predict how much battery time you'll need in the field, and it's also hard to guarantee the performance of individual batteries. So make sure you have some spare capacity. Remember particularly that in extremely cold weather battery life may be reduced by 60 to 80%.

AC power cable

If you're recording an interview in a stationary setting, you can save your batteries (perhaps even recharge them too!) if there's a wall outlet handy and you've brought along the power cable or power adapter for your recorder. Be sure to monitor the recording if you do this, though: in rare circumstances plugging into AC power may create a hum or buzz in your recording.

Headphones

The best way to check the quality of your recordings, while you're making them or afterward. Make sure you have the right plug type for your recorder.

Shoulder Strap, Carrying Case or Equipment Bag

It's best to protect your gear by carrying it in a bag or case. This also keeps the recorder out of sight where it's less likely to invite questions and curious fingers. But if you don't want to do that, a shoulder strap can keep the recorder close at hand when you're on the move.

Adapters and Cables for Special Circumstances

These can include extension cables for when your recorder needs to be farther away from your microphone; a podium clamp or desk stand for the mike; adapter cables to connect your recorder to another recorder, or to the telephone for filing from the field.