The biggest problem with using condenser microphones is their inability to withstand humidity. Krause tests his mics by filling his bathroom with steam, but even though the Schoeps didn't fare well in the bathroom test, he took them to the mountain rainforest of Rwanda, hoping that by keeping them in a desiccant when not in use and "equalizing" them to the environment before using them, he could overcome the humidity problem. The Schoeps failed in three minutes, so Krause turned to his less expensive Beyer M700N(C) hypercardioid dynamic mics, which had survived 45 minutes of steam testing. The Beyers passed the test of sitting three to four hours in the rain.

Krause had the mics mounted atop his head so the wires wouldn't entangle his body, allowing him to dispense with the shock mount and tripod and keep his hands free. He taped rubber Acoustafoam to the mic mounts, taped the mics to the headband of his earphones, and put the whole thing over a San Francisco Giants baseball cap so it wouldn't slip. Krause found the Beyers weren't as sensitive as the Schoeps; they were heavy and a bit noisier, but indestructible. These were the mics Krause was wearing when the gorilla attacked. That's a rock and roll mic," Krause laughs. "It takes a lot more than a gorilla to destroy them."

The latest addition to Krause's microphone arsenal is a $3,400 Neumann RSM 190i-S, a selectable-pattern condenser that offers the choice of shotgun, x/y stereo, or both. It features two capsules on the side and one on the end, along with a choice of sideband pickup patterns: 0, 6, or -6 dB. In x/y stereo, it provides a full cardioid or hypercardioid, and the mid-plus-side (MS) shotgun is very focused. Because it's a condenser mic, the Neumann has humidity problems, but Krause finds it to be an excellent piece of equipment and appreciates its range of options, including a pistol grip that allows it to be either handheld or mounted. Krause puts a Rycote windscreen on the Neumann, which doesn't affect the frequency but does affect the pickup pattern.

Nagra Falls
Krause has recorded in many places and under a variety of conditions, and the 2-track, reel-to-reel, Nagra IV-S recorder has been his closest companion. It weighs 25 pounds with tape supply, batteries, and mics and is awkward to handle in rough terrain, but it has been infallible: it worked admirably despite a plunge from a helicopter. "It's one of those heavy-duty pieces of field equipment you can always manage to fix somehow."

Krause has experimented with a Sony TCD-Dl0 R-DAT but found it unsatisfactory for field work. The R-DAT's tiny, two-hour tapes are light and convenient, but the R-DAT machines don't function reliably in humid conditions. Further, in places like the mountains of Rwanda, where there's no electricity within thirty miles (not even a generator), there would have been no way to recharge an R-DAT power supply, which lasts less than an hour and a half and costs over forty dollars. "If you take an R-DAT in the field, where will you get it serviced?" Krause asks. So he continues to use a custom-made Nagra preamp, Ampex 457 audio tape (at 15 ips), and a Nagra Master noise-reduction unit. As a backup, Krause sometimes takes a Sony TCD5 cassette recorder.

Cleaning Up
Krause's primary application of processing gear is to eliminate wind and other undesirable noise. His most powerful tool is a Macintosh Plus computer with Digidesign's Sound Designer graphic sample-editing software. With creative associate Matt Ward, Krause samples his taped sounds on an E-mu Emulator II or III, then uses Sound Designer to edit out the noise on both sides of the signal.

"Sound Designer is brilliant," Krause enthuses, "I rely on [Digidesign's] software more than any other." For sequencing, he uses Mark of the Unicorn's Performer. Krause also uses analog filters (equalizers), though he recognizes they are limited in their ability to eliminate noise. In addition, he puts an Orban stereo synthesizer on the whale sounds to give them a sense of space and movement.

For some low-frequency applications, especially in his role as an expert audio analyst for legal cases (audio forensics), Krause uses time-based, lowpass, automatic digital filters. According to Krause, "they are designed to eliminate noise, yet leave voices intact without changes in timbre, intonation, prosody [time/meter patterns], or quality." Their principle of operation is adaptive predictive deconvolution. The processor identifies constant and nonconstant sound impulses. Constant impulses represent background noise, and nonconstant impulses are the desired signal. It predicts, based on almost ten million operations per second, which impulses will be in what category. The filter then reduces the level of the constant signal relative to the nonconstant. In addition, it can eliminate noise from the desired signal within the same frequency band(s). However, because their frequency range does not exceed 7 kHz, automatic digital filters are useful mostly in relatively low-frequency applications.

Acoustical Bio-What?

By Steve Oppenheimer

According to Webster, bioacoustics is the branch of science that studies the relation of living beings and sound. Bernie Krause is a proponent of the theory that each location on Earth has a unique environmental aural ambience. He noticed that "every time I moved 100 yards from one location to another, even if there was virtually no change in the environment, the sounds were different. Each location on Earth has its own voice, just as we have our own voice."

The spectrographic footprint of a location is its acoustical biospectrum. Krause theorizes that for a given time of year, time of day or night, weather, and other natural phenomena, these ambient sounds are constant. When one voice drops out, another will eventually take its place in the same area of the spectrum, i.e., a creature fills the available frequency window, keeping intact, overtime, the unique acoustical biospectrum of that place. This theory has been investigated with regard to bird songs, by other researchers.

Krause finds that insects create a constant din in one part of the spectrum, and the other creatures vocalize in different frequency ranges. In the light of natural-selection theory, this is logical. Krause's spectrograms indicate there are regional patterns created by wide-spread species (such as insects) and local patterns caused by species that have a limited range. He tested these theories by recording over a period of several days, at approximately the same time of evening, in three locations 150 yards apart, with similar vegetation, at an altitude of 1,000 feet. The resulting spectrograms are compared to similarly recorded data in other parts of the world. So far, the results have been affirmative.

Krause speculates that changes in a particular acoustical biospectrum may indicate changes in the ecological balance of the location, and he hints at a tie to the Lovelock-Margolis "Gaia Hypothesis." He also thinks that mobile, wide-ranging creatures may use ambient sound as a beacon to find their own special habitats. "There's Earth orchestration and there's human orchestration," Krause states. "After all, composers have been trying to emulate nature ever since the beginning." Krause notes that all musical instruments started from observations of nature-the sound of a taut skin led to drums, wind in the reeds led to flutes-and composers of more recent centuries, such as Vivaldi (Four Seasons), Debussey (La Mer), and Beethoven (Sixth Symphony), openly emulated natural sounds with the orchestra.

Bernie Krause Recordings
(Solo or with Paul Beaver)

Discography by Robert Carlberg

Nonesuch Guide to Electronic Music, Nonesuch, 1968
Ragnarok, Limelight, 1969
In a Wild Sanctuary, Warner Bros., 1969
Gandharva, Warner Bros., 1971
All Good Men, Warner Bros., 1973
Citadels of Mystery, Mobile Fidelity, 1979
Revised Nonesuch Guide to Electronic Music, Nonesuch, 1979
Equator, The Nature Co., 1986
Nature, The Nature Co., 1987
Gentle Ocean, The Nature Co., 1988
Distant Thunder, The Nature Co., 1988
Mountain Stream, The Nature Co., 1988
Morning Songbirds, The Nature Co., 1988
Summer's Evening, The Nature Co., 1988
"Fish Wrap"/"Jungle Shoes" (CD-3), Rykodisc, 1988

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