1 FIELD RECORDING EQUIPMENT OVERVIEW

1 FIELD RECORDING EQUIPMENT OVERVIEW
FIELD RECORDING EQUIPMENT
OVERVIEW
Recording birds, frogs, mammals, insects and other natural sounds can be very
challenging and rewarding. The proper selection of field recording equipment will help you
make the most out of every recording opportunity and will probably save you time and
money in the long run. Equipment choices are very limited due to the specialized
requirements of natural sound recording work. Issues surrounding the choices have to do
with quality, specific application, durability, ease of operation and last, but certainly not
least, the cost. Suitable formats for use in natural sound recording include cassette,
open-reel and digital systems. Microphone systems include the shotgun and the parabolic
reflector. The following sections provide details on the options available to the field
recordist based on our in-house testing and extensive field experience. Hyperlinks to
Manufacturers and Vendors are provided if you desire additional information.
Topic Quick Finder:
Recorders
Microphones/Transducers
Analog
Cassette
Open-reel
Digital
R-DAT
MiniDisc (MD)
MiniDisc (Hi-MD)
Hard-drive
Solid-State
Overview
Shotgun
Parabolic reflector
Omni-directional
Uni-directional
Infrasonic
Hydrophones
Bat Detectors
Playback
Misc.
Headphones
Speakers
Amplifiers
Preamps
Ext Power
Shock-mounts
Cables
Speed Accuracy
Protective case
Reading List
Vendors
Additional info
RECORDERS
Analog Cassette
These popular devices are widely used for recording birds and natural sounds. Among the
cassette recorders we have tested that are appropriate for natural sound recording are
two machines manufactured by the Sony Corporation and one machine manufactured by
the Marantz Corporation.
Sony currently offers one monaural machine, the TCM-5000EV ($479.00) and in limited
quantities one stereo machine, the TC-D5ProII ($1175.00).
The TCM-5000EV mono machine features a third head that serves as a playback/monitor
head. This feature allows the recording to be monitored as it is being created which can
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assist the user in determining the quality of the recording. The recorder has a somewhat
limited high-frequency response that falls off rapidly above 10.0 kHz. The electronic
design of the recorder dictates the use of Type I tapes only. It also offers a good built-in
playback speaker. Input/output connectors utilized are 3.5mm mini-jacks that are not
very durable for field use. The response time of the VU meter is quite slow which makes
it highly inaccurate for most natural sound recording work.
The TC-D5ProII stereo machine is a solid performer that offers considerably better high
frequency response that is usable up to roughly 15.5 kHz. The recorder has the ability to
record on cassette Type I, II, & IV tapes. This unit also has adequate VU meters, an
additional peak level indicator light and a small internal monitor speaker. Input
connections are made via professional 3-pin XLR style connectors and output
connections are RCA phono jacks. This machine is a two-head version that does not
permit off-tape monitoring while recording.
Marantz offers a monaural machine, the PMD-222 ($402.00)
The PMD-222 mono recorder features a third head that serves as a playback/monitor
head. This allows the recording to be monitored as it is being created which can assist
the user in determining the quality of the recording. Type I, II, & IV cassette tapes can be
used with this machine. The recorder also includes a reasonably good VU meter and a
peak level indicator light. A professional 3-pin XLR style connector is used on the
microphone input and the output connections are made via RCA phono jacks. High
frequency response is usable up to about 14.5 kHz. This unit also includes an internal
playback speaker.
The choice between the mono recorders is fairly straightforward. The Marantz PMD-222
performs (records) much better than the Sony TCM-5000EV however, if the recorder is
to be used for serious playback work the user will probably find that the Marantz
speaker is not adequate for the task. One must consider adding an external powered
speaker such as the Radio Shack model 277-1008 to equal what the Sony TCM-5000EV's
speaker can provide.
When evaluating various models there are certain capabilities to consider. One of the
most important features to look for is a manual record level control. The automatic level
control (ALC) that is found on many portable cassette recorders is very handy for
dictation but is totally ineffective for recording natural sounds. Machines that support
Type II or Type IV tapes will also do a better job than machines that can only support
Type I tape. Type II & IV tapes offer better high-frequency response, lower distortion
and better signal-to-noise ratios. Noise reduction systems, such as Dolby or DBX,
although a benefit for music and voice recordings will not work well for recording natural
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sounds. While these systems certainly will reduce tape hiss, they can also add distortion,
breathing, pumping and limit the amplitude of the higher frequencies of many bird
vocalizations. If you require the ability to play back sounds in the field, you will want to
consider a machine that offers a built-in speaker. The decision between stereo and mono
is governed by the uses you have for your recordings. For most bird recording work,
stereo might be an unnecessary complication. However, if you are interested in recording
ambient environmental sounds, or want the ability to discern individuals that might be
calling simultaneously, then a stereo machine is preferred.
RECORDERS
Analog Open-Reel
The open-reel recorder was until recently one of the top choices of the seasoned
professional field recordist. Although now being displaced by newer, lightweight, highresolution digital systems many of these machines are still in use. The advantages are
sheer durability, fidelity, long battery life, immunity to humidity-related problems, and
accuracy. The disadvantages are generally weight, higher cost and frequent tape
changes. Three companies, Nagra, Uher and Stellavox manufactured portable audio openreel recorders suitable for natural sound recording work. To the best of our knowledge
only the Nagra and Stellavox are still currently available. Nagra offers a stereo machine
(Nagra IV-S) that costs about $14000.00. Stellavox offers the SP-9 for about
$5000.00-$7000.00 depending on head block configuration. Good used machines can
often be found at substantial savings. Our experience has shown that the Nagra is the
most durable tape recorder that one can purchase. They simply do not fail. The Lab has
25-year old Nagra's that are still in regular service. One other important factor to
consider is the availability of open-reel tape stock. Current market trends are favoring
digital recording devices, however there is still one analog tape manufacturer Quantegy,
Inc. offering stocks for these portable machines.
RECORDERS
Digital
R-DAT
The R-DAT (Rotary-head Digital Audio Tape) format while quite popular in the mid 1990’s
is slowly disappearing from the market place. Very similar in design to a VCR (video
cassette recorder) only much smaller this device uses a R-DAT cassette tape which
measures 2 7/8" x 2 1/16" x 3/8". A variety of lengths are available which permit
continuous recording or playback for up to two hours. This linear PCM-based (uncompressed data) recording system offers very ultra-low distortion levels and is immune
to speed errors, tape noise (hiss) and non-linear frequency anomalies (within its usable
bandwidth) which is typically 20Hz-22kHz.
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Portable R-DAT recorders are small and relatively lightweight making them very easy to
carry around in the field. Features include real-time tape counters, the ability to stamp
the current date and time on the tape automatically (available on certain models only)
and a built-in indexing system which allows the operator to mark and quickly access the
starting points of up to 99 selections. Professional models also offer low frequency
filters, 48-volt phantom powering for microphones and incorporate high-quality
microphone preamps.
Although it appears from the above information that R-DAT is the answer to all field
recording problems and needs, there are problems and pitfalls that one should consider
before purchasing an R-DAT machine.
1.
Most of the inexpensive digital recorders being sold today do not allow offtape monitoring (the ability to monitor a recording as it is being created).
Read-after-write, or confidence playback heads, are not commonplace
therefore recording problems cannot be detected during the recording
process.
2.
R-DAT is not a very robust tape format. R-DAT systems utilize a very
narrow tape that is only 3.81 mm wide. Their extremely slow linear tape
speed coupled with a rapidly spinning head assembly writes the data on the
tape in a very compact form. Dirt, dust or foreign debris that migrates into
the machine can potentially cause recording problems. The R-DAT recorder
has built in error correction circuitry that does help offset many recording
errors, however, very large errors can cause signal drop-outs or complete
mutes. Needless to say these problems could render a recording useless.
3.
R-DAT recorders are not the most reliable units for operation in very high
humidity (condensing) environments. Most R-DAT recorders have a "dew" or
humidity sensor built in which shuts the machine down whenever high
humidity is detected. Recording in the tropics or rainforest could therefore
render the machine useless unless proper precautions are taken.
4.
Some R-DAT machines utilize non-standard rechargeable NiCad or NiMH
batteries. The typical recorder will operate for approximately two hours per
battery charge. This means many rechargeable packs must be carried and
kept charged to allow for lengthy recording trips. Other possible means of
powering are available from sealed rechargeable lead-acid batteries
(described in a later section), or standard drycell packs which can be adapted
to work on certain machines.
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Nonetheless, the features of the R-DAT recording systems are simply too great to be
ignored.
The price range on currently manufactured portable R-DAT machines is between $795.00
and $3390.00. Listed below are the units we have field-tested.
HHB PDR-1000 PORTADAT $2790.00 (production discontinued 10/2000)
This rugged professional machine offers read-after-write capability, date
and time stamping, low frequency filters, phantom powering and an internal
playback speaker. High resolution backlit metering is provided. Professional
3-pin XLR style connectors are utilized for microphone inputs and RCA phono
jacks are used for outputs. Digital input and output capabilities are provided.
Field powering is accomplished by proprietary, internal, rechargeable NiMH
batteries, or via 12 volt DC external supply. A standard 4-pin XLR power
connector is provided.
Tascam DA-P1 $1638.00
This is the lowest priced professional recorder built for serious fieldwork. It
does not offer read-after-write capabilities or low frequency filters,
however, it does provide 48 volt phantom powering for microphones. A good
high-resolution backlit meter is provided. Input connectors are professional
3-pin XLR style and RCA phono jacks are used for the outputs. Digital input
and output capabilities are also provided. Field powering is accomplished by
proprietary, internal, rechargeable NiCad batteries, or via DC external supply,
however a special power connector is required.
Sony TCD-D10ProII $3390.00
This rugged machine does not offer read-after-write capabilities, low
frequency filters or phantom power. It does offer excellent backlit metering
as well as date and time stamping on the tape. A small internal speaker is
also provided. Input connectors are professional 3-pin XLR style and RCA
phono jacks are used for the outputs. Digital input and output capabilities are
provided but require an optional specialized cable assembly. Field powering is
accomplished by proprietary, internal, rechargeable NiCad batteries, or via
DC external supply, however a special power connector is required.
Sony PCM-M1 $795.00
This small pocket sized recorder is a pro/consumer device that was not
designed for the daily rigors of field use, but will perform well in the field if
handled with proper care. It does not offer read-after-write capability, low
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frequency filters or phantom powering. Input and output connectors are
3.5mm stereo mini-jacks that are not very robust. Backlit metering and
automatic date-stamping on tape are provided. No internal speaker is
provided so all monitoring must be done via headphones. Digital input and
output capabilities are provided but require an optional specialized cable
assembly. Field powering is accomplished by AA batteries, or via DC external
supply, however a special power connector is required.
RECORDERS
Digital
MiniDisc (MD)
Over the past couple of years we have received many inquiries regarding the use of
MiniDisc (MD) recorders for fieldwork. Standard MD recorders utilize an audio
compression algorithm known as ATRAC (Adaptive TRansform Acoustic Coding) that is
based on psychoacoustic principles. The input signal is divided into sub-bands that are
then transformed into the frequency domain using a variable block length. Transform
coefficients are grouped into non-uniform bands to reflect the human auditory system,
and then quantized on the basis of dynamic sensitivity and masking characteristics.
ATRAC compresses compact disc audio (16-bit 44.1 kHz stereo) to approximately 1/5
of the original data rate with minimal loss in sound quality. This technology permits 74+
minutes of stereo sound to be recorded on a small 64mm optical disc.
Audio compression distorts sound, but in such a way that humans normally can't detect.
The compression method used in MD recorders has frequency and timing constants builtin that are intended to make the compression inaudible to human ears, but which may
make it audible to other species. For instance, humans can't hear a sound at a certain
frequency if there is another, louder sound at a nearby frequency, so the compression
algorithm will leave out the former sound. We can't hear the difference, but it's possible
other species might and any scientific analysis of the compressed sound would have to
work with a distorted version. Additionally, compression algorithms typically can't track
very fast changes in overall loudness correctly, since humans can't hear such changes
very well. Other species (e.g. many songbirds) do have significant variation in amplitude
over very short time periods in their vocalizations. If you try to record such species with
a MD, you'll likely introduce some distortion.
We tested a popular early-entry portable field machine that utilized ATRAC 2 and found
it to be unacceptable for natural sound recordings especially recordings that might be
subjected to scientific analysis.
Newer machines that utilize ATRAC 3.5 & 4.5 versions are considerably better. When
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recordings made on these machines are compared to similar recordings created by highquality analog cassette recorders the results typically favor the MD version. The total
lack of tape hiss, wider frequency bandwidth of the MD system, and lower overall
distortion levels all contribute to favoring the MD. Low-level high-frequency information
that the MD ATRAC system might have masked would have been buried in tape hiss on
the analog cassette version so frequency masking is not an issue when these two
formats are compared.
Two popular current generation MD recorders are the HHB PORTADISC MDP500
($1399.00), and the Sony MZ-N10 ($345.00).
The HHB unit is a professional, rugged, field device that utilizes ATRAC version 4.5. It
features XLR style microphone input connectors, 48-volt phantom power, low frequency
filters, 6-second pre-record buffer, 40-second memory buffer to prevent glitch-free
recordings, large backlit metering display, and a USB port for up/downloading audio data
files directly to both Macintosh and Windows computers. Both optical and coaxial digital
inputs and outputs are provided as well as analog line outputs. Field powering is
accomplished via rechargeable NiMH, standard AA alkaline batteries, or via 12-15-volts
DC external power.
The Sony unit is a small compact Walkman style device that utilizes ATRAC DSP-Type-S.
It features a small, but useful backlit display and manual record level control. Skip-free
“G” protection is provided as well as date/time stamping. Microphone inputs and
headphone connectors are 3.5mm stereo mini- jacks. Field powering is accomplished via
standard alkaline AA style or re-chargeable batteries.
RECORDERS
Digital
MiniDisc (Hi-MD)
Exciting news on the portable recording scene in January 2004 is the Hi-MD. The Hi-MD is
nearly a complete revamping of the original MiniDisc system. Several significant changes
include the Hi-MD media (a new 1.0GB disc), and the ability to record in a linear PCM (uncompressed data) format. These both are important factors for individuals recording
natural sounds. No longer are we constrained by the ATRAC coding algorithm (although it
is still an available recording format choice). Additionally, the 1.0GB disc capacity can
yield an impressive 1-hour/34 minutes of stereo recording time. Using Sony’s new
improved ATRAC 3plus coding @256kbp/s will render 7-hours/55 minutes of recording
time per disc.
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As with all new technologies, machine choices are very limited. The Sony MZ-NH900
(~$300.00) is a small Walkman style machine. Microphone and headphone connections
utilize 3.5mm stereo mini-jacks. Digital record level is provided as well as a small, but
useful backlit display for metering. Anti-skip “G” memory buffer is also employed. A USB
port is on-board for off-loading digital audio files directly to a Windows based computer.
The caveat is that only audio files that were originally recorded via the analog
microphone or line inputs can be digitally transferred via the USB port. Audio captured
via the digital inputs cannot. Field powering is accomplished via NiMH rechargeable or
standard alkaline AA style batteries.
RECORDERS
Digital
Hard-drive
Relatively new on the portable digital recording scene are the hard-drive audio recorders.
These easy to use devices utilize specially formatted, rugged computer hard-drives
(typically 40GB or greater) for storage. The digitized audio is simply stored as data files
on the disk making random access very easy. While a few multi-channel devices have
been available for some time (Zaxcom- DevaII, HHB-PORTADRIVE, and the Aaton-CantarX) the market place has been void of simple two & four channel units. Sound Devices, LLC
is introducing in the 2nd quarter of 2004 two new audio recorders, models 722 and
744T. They are being marketed as the next logical successor to the time-code and
portable R-DAT machines.
The model 722 (~$2000.00) is a high-resolution 2-channel recorder. It will feature highresolution A/D and D/A converters, high-quality microphone preamps, active-balanced
XLR style microphone inputs, 48-volt phantom power, high-pass filters as well as realtime post-record monitoring. A user adjustable pre-record buffer is provided to eliminate
missed takes. A large backlit display for metering is viewable in all lighting conditions.
Digital inputs and outputs are available via either TA3 or BNC connectors. Multiple
sampling rates are supported including 44.1, 48, or 96kHz. Selectable bit-depths are
either 16 or 24. Recording format is un-compressed linear PCM. A 40GB field
removable/replaceable hard-drive is standard. External data interface is via a 1394
(Firewire 400) port. Field powering is accomplished via removable Lithium Ion
rechargeable batteries, or via external 5-18 volts DC. External powering requires a 4-pin
Hirose connector.
The model 744T (~$4000.00) shares many of the above features except it offers 1,2,
or 4 channels of recording plus an additional time-code track. Additional sample-rates
are also standard to conform to the needs of the video/film user.
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RECORDERS
Digital
Solid-state
These recorders are relatively new to the portable audio recorder scene. They offer
many of the features currently available on cassette, R-DAT, and MiniDisc recorders, but
instead of tape or disc, they utilize standard computer compact-flash memory cards or
a Microdrive as storage medium.
Most units offer several recording format choices such as, MPEG1 Layer II & Layer III
compression (commonly known as mp2 & mp3), and 16-bit linear PCM. For high-quality,
natural sound recording, and to avoid data compression the latter must be used. Due to
the increased data rate that linear PCM generates relative to compressed formats one
must carefully select the appropriate sized storage for their specific application. For
example a 512MB flash card will store roughly 7 hours of mono material using the mp3
format @160kbps data rate. Whereas the same 512MB card will only be able to store
roughly 1 hour/36 minutes of mono material in the linear PCM mode utilizing a sample
rate of 44.1kHz.
Currently, flash cards are available in a variety of sizes ranging from 32MB-1024MB.
Microdrives can extend the capacity even further. Although large memory cards and
Microdrives are somewhat expensive right now, this is a growing industry and prices will
continue to drop.
The real beauty of this recording device/format is the ability to create high-quality
recordings stored short-term in a robust format with no moving parts. These can be
easily edited within the device and instantly downloaded into a computer for detailed
analysis, or perhaps to create compact discs for longer-term storage.
One such device the Marantz PMD-670 $695.00 w/64MB card
This device offers many of the same professional features included on other industry
standard recorders. Including balanced XLR style microphone inputs, 48-volt phantom
power, noise filters, internal speaker, 2-second pre-record buffer, one-touch record, and
a large backlit display for metering. Digital audio in/out is accessible via RCA connectors
(S/PDIF format). Line level audio in/out is unbalanced via RCA connectors. Available
data/sampling rates range from a low of 32kbps/mp2 through highest quality at
48kHz/16-bit linear PCM. Audio files are easily transferred directly into a computer by
simply placing the recorded card or Microdrive into a computer attached card reader.
Additionally, a computer data interface is provided that can communicate with a
standard USB compatible port on either Macintosh or Windows based platforms. Field
power options include removable, NiCad or NiMH rechargeable batteries, or 8-standard
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AA alkaline batteries.
A slightly different variation is the new offering from The Fostex Corporation.
Announced in January 2004 is the introduction of the FR-2 Field Recorder ($1499.00
without time-code option or storage media). This is the first solid-state field recorder to
offer up to 192kHz sampling 24-bit operation, making it an ideal choice for recording
situations that demand the highest quality, un-compressed data format possible.
The machine features a 10-second pre-record buffer, balanced microphone inputs via
standard XLR style connectors, 48-volt phantom power, generous sized LCD display for
high visibility in the field, and a tough rigid housing to withstand the rigors of field use. Of
particular note is the “file per take”, and “auto take naming” systems to help organize
and manage sound files within the device.
Recording media supported are PCMCIA: compact-flash or ATA Flash card, and ATA type
hard disk. Sampling rates supported from 22.05kHz-192kHz. Bit depths of either 16 or
24. Full SMPTE time-code is also an option. Field powering is via 4xAA style batteries
(NiMH recommended). The unit can also be powered externally via 12-volts DC with
(special connector required).
File transfers to either Mac or PC are easily accomplished via standard on-board USB
connection. Digital audio I/O is via XLR connectors in both the AES/EBU and S/PDIF
formats.
MICROPHONES/TRANSDUCERS
Overview
Along with a recorder you will need a microphone or transducer. The scope of this
document is limited to 4-basic sound categories: audible range (20Hz-20kHz), ultrasonic
(30kHz and higher), infrasonic (below 15Hz), and underwater sounds.
In the audible range category there are many brands of high-quality microphones
available – Sennheiser, Shure, and Audio Technica just to name a few. We have tested,
and are currently using, the Sennheiser line of microphones. They have proven to be
extremely durable, exhibit very low self-noise figures, offer high output, and depending
on the particular model selected, are almost completely immune to high humidity related
problems.
Capturing ultra-high frequency sounds such as those created by Bats requires the use of
a specialized transducer known as a Bat detector. These devices convert the ultra-high
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frequency sounds down to a frequency range that can be heard as well as recorded.
Capturing underwater sounds also requires the use of another specialized transducer
type, the hydrophone. These specialized devices are covered in detail in later sections.
There are two types of microphones that are directional enough for natural sound
recording at a distance, the shotgun microphone and the parabolic reflector microphone.
To better understand the relative utility of different microphones and parabolas we have
compared their beam-width (angle of acceptance) to the field-of-view of lenses
commonly used on 35mm cameras. This comparison is approximate and assumes that
the frequency of interest is around 2500 Hz. If the frequency of the sound is lower, a
larger parabola is required for equal performance.
Microphone Type
Parabola
Parabola
Parabola
Parabola
Short Shotgun
Long Shotgun
Cardioid (unidirectional)
Omni-directional
Diameter
12"
18"
24"
36"
Lens Size
75 mm
100 mm
135 mm
200 mm
20 mm
28 mm
(fish eye) 8-15 mm
n/a
MICROPHONES/TRANSDUCERS
Shotgun
A good inexpensive shotgun microphone system for general use is the Sennheiser ME66/K6/MZW66 combination. The cost of this system is about $470.00. This modular
system is the combination of the K6 power unit (requires one AA battery), the ME-66
shotgun microphone capsule and the MZW-66 foam windscreen. An additional feature of
this modular system is the K6 power module can also be outfitted with another capsule
the ME-67/MZW-67 that is a slightly longer, more directional shotgun capsule with
windscreen.
The top-of-the-line Sennheiser shotgun microphones are the MKH-60 and the MKH-70
with the latter being the longer, more directional of the two. The MKH series
microphones offer almost total immunity to high humidity related problems, exhibit
extremely low self-noise, and offer very flat frequency response over the usable
bandwidth. Their high sensitivity requires special shock-mounting and wind protection to
make them suitable for handheld field use. Coupled with a Zeppelin style windscreen and a
good shock mount the MKH-60 sells for about $1950.00 while the MKH-70 sells for about
$2200.00.
The entire MKH series of microphones require 48-volt phantom power to operate. This
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48-volt power can either be supplied by an external power-supply or by the recorder if it
is so equipped. External power units include the Sennheiser MZA-14 which sells for
$400.00, the Stewart Audio BPS-1 which sells for $125.00 and the PSC Universal Mic
Supply which sells for about $290.00. Both the Sennheiser and the PSC models also
include dual position, low frequency filter and signal attenuation switches.
MICROPHONES/TRANSDUCERS
Parabolic Reflector
The parabolic reflector system is the combination of a reflector dish, typically between
13" and 36" in diameter, and a microphone. The microphone is positioned in the focal
point region of the reflector (the area where all the collected sound is concentrated).
Parabolic reflectors, by design, yield a tremendous increase in sensitivity without any
added electronic noise. Microphones suitable for use in parabolic reflectors range in price
from $300.00-$1200.00, with the more expensive units yielding flatter frequency
response, improved signal-to-noise ratios and higher signal level overload capabilities.
Listed here are some of the different reflectors manufactured.
1.
The Telinga Pro parabolic reflector is a clear, lightweight 22" reflector available in
several models that include integral high-quality microphones, or as the Telinga
Universal model that is designed to accept other manufacturer's microphones. All
of these models offer excellent rejection to handling noises and can be completely
disassembled for easy transport.
2.
The Mineroff Electronics SME-PR-1000 ($375.00 without microphone) is an 18"
epoxy coated aluminum reflector that includes a pistol grip and adjustable
microphone mount. It also offers a transparent viewing window at the center of
the dish to assist in aiming. This reflector, coupled with an inexpensive microphone
is a perfect starter system for low budget applications.
For the do-it-yourselfer, one can purchase high quality 24"-36" spun aluminum reflectors
that are designed and sold as satellite receiving antennas. These units are perfectly
acceptable; however, they are not supplied with a microphone or microphone mounting
hardware. One can easily create a mounting system with aluminum bar stock that is
readily available from most hardware stores.
Contact:
The Antenna Center, 505 Oak Street, Calumet, MI 49913. Phone 906-3375062, Fax 906-337-5030.
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MICROPHONES/TRANSDUCERS
Omni-directional
Even though omni-directional microphones pickup from all directions they can provide
excellent results when used in the right situations. For example, positioning an omni near
a bird’s song perch can yield fantastic recordings in part due to the close proximity of
the microphone to the bird (greatly reduces ambient background sounds), but also
because it doesn’t matter too much whether the bird is singing directly into the
microphone or changing directions on the perch. The detail captured will be amazing.
Other applications for omni microphones include using them in a parabolic reflector, or in
stereo pairs for undertaking acoustic census work and general environmental recording.
The Sennheiser K6/ME-62 ($360.00) omni-directional modular microphone system is a
relatively low cost option. This is especially true if one already owns a K6 power module
from the Sennheiser modular shotgun system. An accessory windscreen MZW-64 is
recommended.
The high-end omni-directional microphone is the Sennheiser MKH-20 that sells for about
$1170.00. Just like other members of the MKH series, the MKH-20 is almost totally
immune to high humidity related problems. They also exhibit extremely low self-noise,
and offer very flat frequency response over the usable bandwidth. Their high sensitivity
will require special shock-mounting and wind protection to make them suitable for
handheld field use. 48-volt phantom powering is required.
MICROPHONES/TRANSDUCERS
Uni-directional
Uni-directional microphones (commonly known as cardioids or hyper-cardioids) feature a
directional pickup pattern. This means that the device is most sensitive towards the
front of the microphone, slightly less off to the sides, and has the least sensitivity from
the back of the unit. This directivity can be used to ones advantage. For example, by
positioning the backside of a cardioid microphone towards an unwanted noise source one
can significantly reduce the level of the offending noise relative to the sound of interest.
This feature can often help when recording in indoor locations such as aviaries, research
cages, and observation booths. A pair of cardioid microphones can also be used to do
stereo environmental recording where directionality is required.
The Sennheiser K6/ME-64 ($380.00) cardioid modular microphone system is a relatively
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low cost option. This is especially true if one already owns a K6 power module from the
Sennheiser modular shotgun system. An accessory windscreen MZW-64 is recommended.
The high-end cardioid microphone is the Sennheiser MKH-40 that sells for about
$1170.00. Just like other members of the MKH series, the MKH-40 is almost totally
immune to high humidity related problems. They also exhibit extremely low self-noise,
and offer very flat frequency response over the usable bandwidth. Their high sensitivity
will require special shock-mounting and wind protection to make them suitable for
handheld field use. 48-volt phantom powering is required.
MICROPHONES/TRANSDUCERS
Infrasonic
The recording of infrasonic (ultra-low frequency) sounds requires the use of a
specialized microphone. Some of the available models are relatively expensive
“instrumentation” grade devices that are designed for noise and vibration analysis.
These generally offer performance down to roughly 1.0Hz and include models from
Larson Davis and Bruel & Kjaer. There is however an affordable, high-quality solution
providing you aren’t trying to capture sounds much below 4.0Hz. The Earthworks model
QTC-1 is a high-performance, low-noise omni-directional microphone that is usable down
to 4.0Hz ± 1.0dB. It utilizes standard 48-volt phantom power and terminates in a
standard 3-pin XLR style connector.
MICROPHONES/TRANSDUCERS
Hydrophones
For underwater recording the DolphinEAR/Pro ($299.00) is a high quality, low cost
solution. The omni-directional device features a 10-meter cable (other cable lengths are
optional), 600 ohm balanced output that terminates with a standard 3-pin XLR style
connector, and a frequency response of 15Hz-20kHz ±3dB. The transducer is a highoutput MPC (Piezo) style, fully encapsulated in a rugged epoxy case. No power is
required.
MICROPHONES/TRANSDUCERS
Bat Detectors
Bat detectors provide a relatively inexpensive means of listening to and recording Bat
vocalizations. These ultra-sonic signals are way above the range of human hearing and
general use audio recording equipment. The Bat detector electronically converts the
ultra high-frequency sounds down into the range where humans can hear and audio
recorders can capture. There are many, many models on the market. Our hands-on field
14
experience with a Laar model BB-XL detector, coupled to an R-DAT machine has produced
stunning results.
A special thank you to Karsten Passior passior@nexgo.de. He has gone through enormous
lengths to compile the most complete Bat detector comparison listing to date. Through
his kind generosity we are able provide this in-depth comparison. The chart shown below
is a subset of a much larger list of detectors. It contains detectors that are currently
available as well as those recently discontinued. Practical factors like the availability of a
frequency display light (LED or LCD), one or two hand operation, weight, basic noise,
sensitivity, filtering technique, power requirements etc. are used to compare models.
15
Laar
Laar
Specifications Tranquility Laar-Classic
II
NG
Heterodyne
X
X
Panorama
system
Frequency
division
Time expansion
Storage time
Self scanning
heterodyne
system
Built-in
loudspeaker
Headphone
socket
LF output
Laar-3 P
ELV
Stag
Stag
Bat Box
III
X
Microbat
X
Bat
Detector
X
Laar-BB
L
-
Laar-BB
XL
-
Explorer
Laar-PX1
X
Laar-BB
S
-
-
X
-
-
X
X
X
X
X
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
10 + 32
times
1,28 s
-
-
10 times 10 times 10 times 10 times
-
-
-
-
-
-
-
-
-
1,5 + 2,6 3 + 5 s
s
memory memory
512 kB
1 MB
X
X
X
-
X
X
X
5 + 10 s
2s
-
-
-
-
memory
2 MB
memory
512 kB
-
-
-
-
-
-
-
-
-
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
-
X
-
HF output
-
X
X
-
-
-
-
-
-
X
-
Comment
switch
Frequency
display
Frequency
display light
Frequency
range
Bandwidth
-
-
-
-
-
-
-
-
-
-
-
digital
digital
digital
-
-
-
-
digital
analog
analog
LED
LED
LED
-
-
-
-
LED
-
X
low /
high
LED
10 - 200
kHz
± 3 kHz
15 - 150
kHz
± 5 kHz
Bandspread
?
-
Band-pass filter
-
Accuracy ± 0,2 kHz
15 - 150 15 - 160 15 - 160 15 - 160 15 - 120
kHz
kHz
kHz
kHz
kHz
± 5 kHz
-
-
-
-
-
15 - 160
kHz
± 5 kHz
-
10 - 100 20 - 120
kHz
kHz
?
± 8 kHz
-
-
26 / 46
kHz
?
-
-
-
-
-
-
-
-
-
-
-
?
?
?
?
?
?
100%
?
?
?
Sensitivity
133%
133%
133%
115%
115%
115%
100%
133%
100%
100%
100%
Basic noise
low
very low
very low
low
low
low
low
very low
standard
standard
standard
2x9V
2x9V
2x9V
2x9V
2x9V
9V
9V
9V
9V
9V
Power supply 4 x 1,5 V
voltage
AA
Working time
?
8 h by
8 h by
8 h by
8 h by
8 h by
8 h by
6 h by
8 h by
8 h by
accu
accu
accu
accu
accu
accu
accu
accu
accu
Size (l x b x h) 155 x 90 x 196 x 100 x
196 x
196 x
196 x
196 x
157 x 84 157 x 84 140 x 90 120 x 67 106 x 62
mm
48
54
100 x 54 100 x 54 100 x 54 100 x 54
x 30
x 30
x 48
x 32
x 24
Weight
?
490 g
520 g
520 g
520 g
520 g
490 g
490 g
180 g
230 g
118 g
Handling two hand
8 h by accu
two hand
two hand
-
head phone
Price ca.
966€
Vendor
2
Accessories
Notes
898€
head
phone
1124€
two
hand
head
phone
1378€
two
hand
head
phone
1508€
two
hand
head
phone
1686€
one
hand
head
phone
827€
2
2
2
2
2
not
available
not
available
remote
input
remote
input
remote
input
16
one hand one hand
head
phone
456€
-
one
hand
-
one hand
71€
231€
101€
2
2
2
2, 7
1, 2, 7
whith
CD-rom
whith
CD-rom
-
good for
children
Bat detector vendor contacts:
1=
http://www.juedes-ultraschall.de
2=
http://www.vonlaarmedia.de
7=
http://www.batbox.com
PLAYBACK
Headphones
The ability to monitor and evaluate the quality of your recordings in the field is
absolutely essential. The loudspeaker that is incorporated in the recorder (if so
equipped) is not adequate because it can only be used in the playback mode. Good quality
headphones allow you to monitor the incoming signal while the machine is in the record
mode, thereby facilitating proper aiming of the microphone.
Another added benefit, provided the recorder being utilized is equipped with a third head,
or in the case of a digital recorder either a confidence head or real-time post record
monitoring, is the ability to monitor the quality of the recording as it's being created.
Additionally, if there is a problem with the recorder, tape, microphone or cable, using a
pair of headphones will allow you to identify the problem in the field and perhaps rectify
it before the recording actually begins, rather than finding out hours, or perhaps days
later that your recording was flawed.
The choice of headphones is highly personal as to style, isolation and comfort.
Headphones must, however, provide an appropriate electronic match to the tape
recorder thereby insuring adequate output level. The model selected should also offer
some degree of isolation from ambient noises so you can listen accurately to your sound
source.
A few of our favorite headphones are the following:
AKG K-240 Studio (high isolation rating and good output) $159.00
Sony MDR-7506 (good isolation rating and high output) $95.00
Sennheiser HD-25SP (lightweight with medium isolation rating) $113.00
It is important to note that with many cushioned styled headphones, that certain types
of insect repellents can over time disintegrate the foam cushion material. This also holds
true for the foam material used on many microphone windscreens.
17
PLAYBACK
Playback speakers
We are often asked to suggest playback speakers that can be coupled to a portable
recorder or a compact disc player for census/monitoring fieldwork or as a stimulus in
research.
For relatively close work (under 100') the Radio Shack #277-1008 ($12.00)
amplified speaker is a good inexpensive choice. It’s very small, lightweight,
and if not played too loudly, offers reasonably good quality sound for
frequencies in the 1.0kHz-7.0kHz range. The effective radiation pattern is
directional.
For slightly longer working distances, but with the added requirement of good lower
frequency response, the larger, heavier Mineroff Electronics SME-AFS amplified speaker
($185.00) offers very good sound quality over a usable frequency range from roughly
100.0 Hz-12.0 kHz. This device weighs 3-lbs. and runs off of 6-standard AA style
batteries. The radiation pattern is directional.
An option for long-throw medium frequency (400Hz-10kHz) applications is the Anchor
Audio model Megavox PB-35 ($600.00). This device weighs in at only 15 lbs, yet can
deliver 126dB SPL @ 1/meter. On-board 12-volt rechargeable battery provides 6-10
hours of operation. The unit offers line-level input via a standard 1/4” phone jack that
can easily be fed from a cassette or CD player (RCA to 1/4” adapter available at any
Radio Shack store).
For omni-directional playback, the Soundsphere models Q6, Q8 and Q15 are the
recommended choices. The exact model is determined by ones specific bandwidth and
power requirements.
Model
Weight
Frequency range
Max SPL
Sensitivity
Q6
Q8
Q15
8-lb.
22.5-lb.
45-lb.
70Hz-17kHz
55Hz-17kHz
35Hz-15kHz
103 dB
114 dB
122.5dB
88dB SPL@ 1meter/1watt
94dB SPL@ 1meter/1watt
97dB SPL@ 1/meter/1watt
These are not powered speakers and therefore require separate power amplifiers (see
amplifier section).
PLAYBACK
Amplifiers
Occasionally the need arises to utilize non-amplified speakers in the field. Reasons
18
include having to generate higher than normal sound pressure levels for very long
distance coverage, or perhaps trying to broadcast very low frequency sounds. Both of
these require substantial power (watts) and large drivers (speakers). The best solution
is found in the car stereo marketplace. Companies like Crutchfield offer a wide range of
12-volt DC powered amplifiers in both mono & dual channel configurations. Wattages
range from roughly 40-300 watts per channel with offerings from industry leading
companies like Sony, Alpine, Rockford-Fosgate, Kenwood, and US Acoustics.
MISCELLANEOUS
Preamps
Our fieldwork has revealed that the microphone preamps in many of the recording
devices described above, although very quiet, do not always offer adequate gain under
certain distant birdsong recording circumstances. High quality outboard preamps are
available from several manufacturers that can help solve this problem. Another option
available for the digital recording devices is to utilize a good external combination
preamp/A/D converter. This offers the best of both worlds by providing not only a
significant signal gain improvement, but also a dramatic improvement over the stock
A/D converters found in most digital devices.
Grace Design, Inc. offers the Lunatec V3 that sells for about $1600.00. This state of
the art device is a two-channel, ultra low-noise preamp plus a high-resolution A/D
converter system. It features 48-volt phantom powering, switchable high-pass filters,
built-in mid/side recording matrix, and extensive metering capabilities. On the A/D
converter side it handles sample rates up to 192kHz and bit depths of up to 24. Both
professional and consumer digital formats are supported. Field power is supplied by an
external 6 or 12-volt DC battery pack (not supplied).
Sound Devices, LLC offer two, high-performance, low-noise preamps. The MP-1 (single
channel) and the MixPre (dual channel) sell for about $420.00 and $855.00 respectively.
Both units feature switchable high-pass filters and 48-volt phantom power. Two AA
batteries are required for power.
Benchmark Media Systems, Inc. offers the MicMan Jr. that sells for about $435.00. This
preamp is a high-quality, two-channel, high gain, low noise device. It does not offer 48volt phantom power. Field powering is accomplished via a pair of 9-volt alkaline batteries.
MISCELLANEOUS
External Power
Many of the newer digital recording systems are quite power hungry. This factor coupled
19
with the short running time offered by factory supplied rechargeable batteries, and the
memory effect that these types of batteries seem to develop over time can be quite a
hassle for the field recordist.
Eco-charge offers external powering options for many digital recording devices. They
utilize sealed, lead-acid rechargeable batteries that offer much greater running times
(4-6 hours or more per pack depending on machine) and can be recharged over and over
without any negative effects. The packages offered typically include two battery packs
complete with carry cases, shoulder or belt straps, smart recharger and all necessary
interconnecting cables. The up front cost might seem a little high, but over the long haul
it is certainly worth every dollar spent.
MISCELLANEOUS
Shock mounts
One of the major problems encountered during field recording is handling noise. This noise
is transmitted through the body of the microphone and is recorded along with the
primary sound of interest. There are various shockmount systems available that are
designed to reduce this interference. An inexpensive and somewhat universal model is
the Audio Technica AT-8415 that sells for about $50.00. An alternative to buying a
shockmount is to build your own. Click here to view plans.
MISCELLANEOUS
CABLES
Often overlooked, yet very important, are the interconnecting cables that couple the
microphone to the recorder. The best microphone/recorder combination is only as good
as the cable that links them together. High quality cables are often 4-conductor (two
twisted pairs) surrounded with a braided shield. These offer the highest immunity to
stray electromagnetic and RF interference. Quality cables are a bit more expensive than
run-of-the-mill style, however they will generally last longer and perform better. Some
manufacturers offer cables that are extremely flexible, even in very low temperature
environments. Cable flexibility helps lower handling noise, reduces stress and strain on
machine connectors and is easier to coil when the recording session is complete.
Consider carrying a spare cable set; it is cheap insurance.
The Canare Cable Company offers the model L-4E5C StarQuad (lightweight) and model L4E6S StarQuad (heavy duty). These are both high-performance cables that are
extremely flexible and durable.
The Belden Cable Company offers the Optima-Hi-Definition Quad and Belden Brilliance
20
Quad. Both offer reasonable flexibility, but are able to withstand more rugged field abuse
due to their heavier outer jackets.
MISCELLANEOUS
Speed accuracy
Cassette machines are especially prone to speed variation problems. These variations
can occur from tape to tape or even within any given tape. The age of the recorder,
calibration, temperature and the quality of the shell that houses the tape all factor into
the speed accuracy issue. If your recordings are to be used for any kind of scientific
analysis work then knowing the exact speed is a must, as tape speed directly affects
how accurately the signals recorded can be replayed on other equipment. An essential
tool to help solve this issue is the pitch pipe or tuning fork. If a known pitch, e.g. A-440,
is recorded every so often along the tape, it will be possible at a later time to adjust the
playback speed of the recorder to match the original recording. Pitch pipes or tuning
forks are available from most music stores and are not very expensive.
MISCELLANEOUS
Protective cases
Audio recorders are delicate precision devices, especially the digital versions. Providing a
high quality field case for your recorder can prolong its useful life and also help insure its
reliability. Dirt, dust and moisture can raise havoc with the internal mechanisms of these
machines greatly reducing motor and bearing life and creating excess drag coefficients
on other moving assemblies. This can lead to premature mechanical failure or other
recording problems.
The Porta-Brace Company manufactures high quality rugged field cases that we use on
every piece of recording gear we own. They are constructed with heavy- weight, padded,
Cordura nylon material. Flaps, held shut with hook & loop style fasteners provide easy
connector access. Areas over switch panels and meters are covered with a clear, yet
flexible plastic material. Shoulder straps are over-designed for maximum comfort on
even the heaviest recorders. Extra compartments are usually provided for spare cables,
tape, etc. These cases are not waterproof, however they are water repellant. Additional
padding helps provide extra protection to the recorder in the event the machine should
fall or be dropped during field use.
MISCELLANEOUS
Reading list
Since it is impossible to cover all of the factors that should be considered when choosing
21
a recording system or method of using said equipment we have included a reading list of
books and articles that can be very helpful. Some of the books are out of print, but your
local library or bookshop may be able to help locate copies.
TECHNICAL
1.
"Techniques for Audio Recording Vocalizations of Tropical Birds"
Gregory F. Budney and Robert W. Grotke
in Ornithological Monographs, Volume 48, 1997
2.
"Factors to Consider in Recording Avian Sounds"
David C. Wickstrom
In Acoustic Communication in Birds, Volume 1
eds. D.E. Kroodsma, E.H. Miller, and H. Ouellet
Academic Press, 1982
3.
"Sound Recording"
David J. Tombs
David & Charles, Inc., 1980
North Pomfret, Vermont
4.
"Wildlife Sound Recording"
John B. Fisher
Pelham Books Ltd., 1977
London
5.
"Recording Bird Sounds"
James L. Gulledge
The Living Bird
Fifteenth Annual
Cornell Laboratory of Ornithology, 1976
-A good general introductory paper to natural sound recording even
contains some dated information.
AUDIO THEORY & SOUND RECORDING
1.
"The Science of Sound"
Thomas D. Rossing
Addison-Wesley Publishing Company, 1982
Reading, Massachusetts
-Covers acoustic theory and science.
22
though it
2.
"Practical Recording Techniques"
Bruce & Jenny Bartlett
Mix Bookshelf 1992
6400 Hollis Street
Emeryville, CA 94608
Phone 800-233-9604
Fax 510-923-0369
<http://www.artistpro.com/>
-A very good all around reference for the beginner or moderately
experienced recordist. Descriptions of the recording process, types
microphones, microphone technique etc. are covered.
3.
"The Recording Studio Handbook"
John M. Woram
ELAR Publishing Company, Inc., 1982
Plainview, New York
4.
"Sound Recording Practice"
John Borwick
Oxford University Press, 1980
5.
"Sound Recording"
John Eargle
Van Nostrand Reinhold, 1976, 1980
of
MISCELLANEOUS
Vendors
Unless specially noted within specific sections, all of the items described in this paper
can be purchased through the following vendors.
Marice Stith Recording Services
59 Autumn Ridge Circle
Ithaca, NY 14850
607-277-5920 (voice)
607-277-5942 (fax)
msrsithaca@aol.com (e-mail)
Full Compass Systems
23
8001 Terrace Avenue
Middleton, WI 53562
800-356-5844 (voice)
608-831-6330 (fax)
Sweetwater
5335 Bass Road
Fort Wayne, IN 46808
800-222-4700 (voice)
260-432-1758 (fax)
ADDITIONAL INFORMATION
For more specific information about bird song recording equipment or technique, please
contact:
Robert Grotke
Supervising Audio Engineer
Macaulay Library, Cornell Lab of Ornithology
159 Sapsucker Woods Road
Ithaca, NY 14850
607-254-2409 (voice)
607-254-2439 (fax)
audioequip@cornell.edu (e-mail)
© 2004 Macaulay Library, Cornell Lab of Ornithology
This document may not be reproduced and distributed in any manner without the written
permission of the Macaulay Library.
DISCLAIMER
References to equipment, manufacturers and sources included in this document do not
constitute an endorsement by the Macaulay Library, Cornell Lab of Ornithology. Listings
may not be complete and prices may vary.
24
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