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My dad told me the story of a recording he made in 1954 of a piano
recital given by his sister when she was graduating from music college.
It was a special event in a big hall with a full concert-size Steinway
grand. His rig was one of the most portable recorders available at the
time—a one-channel Magnecorder reel-to-reel tape machine in a two-piece
travel case weighing 65 pounds. That was portable recording then—now,
we can carry around a miniaturized digital recorder, complete with stereo
microphones, in a coat pocket. The entire package weighs less than 10
ounces, and is about the size of the level meter on the 1954 Magnecorder.
High quality “pocket recording” is now a reality.
The size reduction in portable recording equipment has been an incremental
process. For years the smallest battery-operated pro audio recording machine
you could get was made by Nagra in Switzerland. It weighed six or seven
pounds and cost around $5,000. Electronics companies made valiant efforts
to miniaturize and improve portable recorders using the familiar compact
cassette format, and brought the size down to impressively small dimensions.
But even with Dolby or dbx noise reduction built in, these units failed
to deliver pro-level recording quality, except in a few voice-only or
sound effects gathering applications. If you wanted portability for master
quality music recording, machines like the Nagra remained the only weapon
of choice.
Miniature DAT
The introduction of
the diminutive Digital Audio Tape (DAT) format in 1988 changed everything
for miniature field recording. With a tape cartridge size of only 2"x23¼4"x3/8",
it was only a matter of applying existing design and manufacturing techniques
to come up with tiny handheld machines capable of storing up to two hours
of master-quality digital recording. Nearly every major recorder manufacturer
offered a miniature battery-powered DAT recorder.
I bought my first “pocket DAT” around 1993—a one-pound unit by Denon—and
it immediately changed my approach to recording. Freed from the need for
an AC power source (the unit had a NiCad battery with more than two hours
run time), I could record just about anywhere, as long as there was ample
blank tape. The mic preamps in the unit were nothing to get excited about,
but weren’t too bad, either. After building adapters to mate the standard
mic connectors to the recorder’s 1/8" miniplug inputs, I was ready for
action.
I took the recorder into environments where I wouldn’t have bothered
trying to record before—small clubs to capture an Irish acoustic band,
construction sites for environmental sound effects gathering, my own concerts,
where I began getting the best “board tapes” ever—and even made casual
recordings of my own guitar playing. I realized that the ease of doing
it made all the difference. My entire kit of equipment was in a bag weighing
a few pounds (though the cost was a few thousand dollars).
It also made
a difference that I wasn't scaring anyone with formidable-looking gear.
How many times do subjects, even professional performers and actors, change
their attitude and/or freeze up when a photographer, videographer, or
recordist shows up? With my pocket DAT setup, I raised no eyebrows, and
even if they knew I was recording, it just didn't look like a rig that
would give master-quality results. (Note: I do not make recordings of
musical or theatrical performances without explicit permission.)
The DAT format
is fairly robust, with the tape protected inside a sturdy plastic shell,
but it's still tape, and tape with always have the downside of being fragile.
DAT tape is thin, and must move accurately across a rapidly spinning head-drum
assembly. Anyone who's used DAT for any period of time has seen tapes
"eaten" due to wayward transport problems.
With portable
DAT machines, another nagging problem shows up—moisture. Any moisture
or condensation buildup on the head drum assembly causes the tape to bind
and snarl, and when transports are moved from a cold environment to a
warm one, condensation can easily occur inside the machine. Many DAT machines
have internal moisture sensors that will shut down the machine if condensation
occurs, but they you could find yourself without a recorder at a critical
time.
Then Came
MiniDisc
In 1992 Sony introduced a new recording format called MiniDisc. With
specifications rivaling the DAT format, and with almost none of the problems
associated with fragile tape, it looked too good to be real. Now after
eight years and five generations of refinement, MiniDisc (MD) is a prime
format for portable recording. Some field recordists are totally sold
on its virtues, and in broadcast work, for both radio and TV sound, the
MiniDisc format has firmly taken hold. If, after grueling technical trials,
these hard-core professionals (including the BBC and US national networks)
have embraced the format, it has to be good.
While DAT takes
criticism for potential mechanical and tape problems, the mechanically
stable MD format has been called into question for audio quality issues,
regarding its use of data compression. The MD data compression system,
known as ATRAC, is probably the most sophisticated audio data compression
technique ever created. It compresses digital audio data at a 5:1 ratio,
meaning that about 80 percent of the original data is thrown out. It would
seem impossible to preserve audio quality with that much missing, but
actually the data isn't thrown out—it's recoded by a special computer
processor into a much more compact form.
As another
real-life example, data compression is used in digital cameras, too, and
in that application they get away with using huge compression ratios of
up to 25:1 but the loss is barely perceptible in the resulting images.
The ATRAC system yields recordings that sound equivalent to DAT or CD
quality in almost every way, and few discerning listeners—in double-blind
listening tests—can tell the difference.
MiniDisc
Portables
DAT tapes are small, but MiniDisc media is even smaller. The disc itself
is encased a square protective package just 2.2" on a side. The MiniDisc
recorder can be made amazingly small because the mechanical parts (a moving
laser head and rotating drive motor similar tow hat's found in a CD player)
are much simpler than those of a digital tape transport. In fact, the
average pocket MD recorder is just 3"x3 1/2"x1" and weighs about nine
ounces! Inside this wondrous gismo are (typically) a decent mic preamp,
optical and analog line inputs, a 24-bit A/D converter, and a complete
set of editing functions. Where miniature DAT machines can record for
around two hours on a set of batteries, MD portables get four to 10 hours
for a couple of AA rechargeables.
Beyond sheer
portability, MD has a strong advantage in portable recording that comes
from the inherent random-access nature of digital disc recording. With
tape machines, before making a new recording on a tape you've already
used, you have to make sure that you are at the end of the old recorded
material, or you will obliterate it with the new material. In most MD
machines, this process has been made completely foolproof—when you press
record, a new track is automatically created and that's where the new
recording goes. (Most manufacturers' designs work this way, but ironically,
Sony, inventor of the MD format, persists with including an "end search"
button that you must press when making a new recording on a previously
used disc.)
Mics and
Plug-In Power
To make good recordings, you gotta have good microphones. Although the
history of microphone development is many times longer than the quick
evolution of miniature recording machines, the best microphones are still
fairly large items, and the recent trend has been toward larger, not smaller,
designs. Add in the required hefty mic cables and paraphernalia required
to supply phantom power, and you can easily end up with the microphone
kit being many times the size and weight of the recorder itself. For successful,
self-contained pocket recording, we need miniature microphones.
Most truly
miniature high-quailty mics are going to be of the electret condenser
variety. Why? because these are the designs that can be shrunk to the
smallest dimensions. Standard condenser mics need a considerable amount
of internal electronics to create a polarizing voltage for the element,
and circuitry to match the high impedance of the capsule with the input
electronics of consoles and recorders. Electret condenser mics need no
polarizing voltage, and just a couple of volts to run an internal buffer
amplifier. Many portable recording nits, both DAT and MiniDisc, supply
this "bias" voltage via a feature called plug-in power. It is a standardized
system, with specifications agreed upon by both the recorder and microphone
manufacturers. Here is the spec: The microphone connector will be a 1/8"
stereo (tip-ring-sleeve) mini-jack , and the machine will supply approximately
1.5 volts DC to that input. Most machines won't like it if you try to
use microphones that don't conform to the specification (e.g., older miniature
electret condenser mics that have their own self-contained battery power
sources, or standard dynamic mics). The good news is that there are numerous
affordably priced plug-in power mics that will yield excellent results
with the new recorder designs.
On higher end
DAT and MD recorders, you will often find quality built-in mic preamps
with standard XLR microphone connectors, which can directly accept a wide
range of microphones. These are not exactly "pocket" machines, though,
and are the size of a medium hard-cover book with a weight of around three
to four pounds. The minuscule dimensions of pocket recorders rules out
using rugged XLR connectors, and we must learn to live with relatively
fragile 1/8" jacks if we want pocket portability.
The Right
Microphone
There are times when full-size, discrete microphones are appropriate to
use with a pocket recorder, but more often, specialized miniature microphones
are best. The most important thing to remember is that the quality of
the mic and preamp determine the quality of the recording. There is no
way to make a bad mic sound good, and post-processing of recordings is
much easier if the initial quality of the recording is high.
Several small
specialty companies have developed miniature stereo microphones designed
specifically for live recording with miniature DAT/MD machines. In general,
their designs are based on miniature microphone modules form sources like
Audio-Technica and Panasonic. The best of these mics are excellent, and
the companies have created many special-purpose mics as well as general
purpose stereo pairs.
One of the
most crafty and useful designs is the "T"-style microphone from Sound
Professionals. This ingenious little stereo mic is about the size of a
drum-tuning key, and fits directly into the mic jack on a portable recorder,
with no cable at all. The recorder/mic combination becomes a one-piece
handheld "soundgrabber," unencumbered by cables. For about $50, this mic
is great for general recording and excels at lecture/interview applications.
At the other
end of the micro-mic price range is the DSM series from Sonic Studios.
These mics feature a pair of miniature premium omni mic capsules adaptable
to a number of interesting configurations. The applications include attachment
to the earpieces of a user's sunglasses, and attachment to an available
dummy-head for binaural/stereo perspective recording. These mics have
gotten rave reviews for their performance in acoustic concert and classical
music settings.
In the middle
range are versatile mics like the Sound Professionals SP-CMC4 Premium
Cardiods, a set of two matched miniature units based on the Audio-Technica
AT-853 capsule. These microphones are available with integral miniature
clips that allow them to be used in many different ways, and boat impressive
specs (frequency response of 30-20kHz and a signal-to-noise ratio of 67
dB).
High SPL
Options and Filters
Sometimes you need to record sources that are very loud. While plug-in
power connections provide adequate voltage to microphones under most conditions,
upping the voltage to the mic gives more headroom, and the ability to
deal with truly intense sound sources, such as rock bands in large venues.
The tool that's available is called a battery box or auxiliary battery
supply. Most provide power from a 9-volt battery, and allow mics to handle
sound pressure levels up to 145 decibels. Some of these battery supplies
feature bass roll-off filters to help control the low frequency environmental
rumble that is often encountered outdoors and in large buildings. The
battery boxes are easy to use—just plug the mic set into the box, and
the box into the recorder input, and voilà, no more blown-out, distorted
concert tapes. Some recorders, including those from Sony, feature built-in
attenuator pads that can be switched in to tame excessively loud levels
before reaching the microphones.
Pocket Recording
Communities
While portable DAT and MD recorders have not caught on with the general
public , the niche market for pro and amateur recordists is healthy and
thriving. On the Internet, through web sites and mailing lists, several
communities of portable recording enthusiasts have formed. There are may
subsets of this group, ranging from audio professionals to "stealth" concert
tapers who trade copies of their illicit recordings via the net. In general,
the online pocket recording communities are just groups of people interested
in the concept of portable recording, and fascinated by the jewel-like
miniature gizmos we use to accomplish it. Some recordists are interested
only in making compilation recordings of their favorite albums to listen
to in the car, while others are pushing the envelope of live recording.
DAT fans congregate
at a site called DAT-Heads (www.eklektix.com/dat-heads),
and MiniDisc proponents find tons of information at sites like The MiniDisc
Community (http://www.mini-disc.org/) and The
MiniDiscussions Page (http://www.minidiscussion.com/).
Besides publishing lots of equipment reviews and opinions, they feature
focused, topical mailing lists and discussion groups where you can air
your views and seek advice from others.
Get Out
There and Record
Nearly every home recording enthusiast can utilize the unique capabilities
of portable recording devices. It's been said that you never understand
how playback systems really sound until you make a live recording of a
musical performance, then go back and listen to it at home. You begin
to understand the huge disparity between real life, and the attempt to
recreate it with amps and speakers. Making a good live recording with
minimal equipment is one of the most rewarding projects you can undertake.
If you've never done it, you're in for a thrill.
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