It is a pilgrim’s journey fulfilled to listen to a wetland. Nowhere else is life so full of exuberant jubilation. Here, at the intimate embrace of water and land, we may listen to life at its fullest celebration. Yet this is a difficult soundscape to design, mainly because the original music is so complete, yet fragile, and easily broken.
Wetland, as used here, includes places with standing fresh water such as swamps, marshes, ponds, and lakes. Some are ephemeral, some perennial. To master Wetlands you must follow a sequence of design steps: determine sunlight, establish the characteristics of the water (temperature and calmness), estimate the maximum distance to the auditory horizon, and finally identify all habitats within your design area and produce a separate soundscape pyramid for each. But prior to that, as in every sound design process, you must ask, What is our story?
STORY
Every sound design necessarily tells a story — one that often requires time to fully hear and understand. Sometimes the story is simple — a large splash (something substantial dropped into water) with a resounding thud (indicating object shape); then echoes off a wall with resonance (possibly a forest). As the next sound occurs, more information is gathered, albeit often subconsciously, and the sound portrait comes into focus to reveal a thriving wetland. When we listen authentically, allowing ourselves to respond intuitively, we learn that each sound conveys an emotion, at least if well-recorded. A poorly recorded sound or ambience comes across as dull and emotionless. To do your best work as a sound designer you will only use sound files in your design that evoke emotion from you. If it feels dull to you, how can you expect your audience to like it?
Although you must ultimately please your boss or client, ignore them while you design. This is your private experience for now. Only you can feel what you feel, so feel it bravely — don’t try to explain it to yourself or anyone else.
Such visceral artistic expression is required for wetlands because there are emotions here, perhaps found nowhere else, a tribal urge to belong to something greater than ourselves.
For example, at sunrise bird populations and at nighttime, frog populations reach trance states. (I know what you’re thinking — How can he say that! Listen first and then decide.) The wetland chorus starts with individual voices calling, singing or croaking, seemingly a bit randomly at first. As this social event continues to build over time, something changes. We hear the total chorus volume increase and decrease in a rhythmic pulse, slow and weak at first, and then much quicker and more defined. Then the pulsing chorus separates and all but one wetland area lowers its collective voice. Then, an adjacent area rises up, initiating a wave that circles the wetland and sometimes ripples back and forth across it. Because each cycle or wave may last a minute or more, few people hear this trance-chorus unless they remain to listen long enough for their mind to learn the patterns, which it will do automatically. Hear the patterns. Know the story. So tune in, let go, trust. (Something rare in our modern world.) Once we give up, let go, and trust, we are then ready to listen authentically, intuitively, emotionally. The rest of your sound design will be more persuasive as soon as the audience submits to this higher reality. So use a wetland trance event fairly early in the production if you can, and resist the temptation to save it for the grand finale. Keep it in the background. The best sound designs are barely noticed and effective because they feel so natural.
SUNLIGHT
As the seasons cycle through temperate wetlands volume levels change. Winter’s silence eases into late winter’s quiet, followed by early spring’s awakening, then onto spring’s full crescendo! Summer and fall bring a gradual sonic retreat. This is the sound of the orbit of the Earth around the Sun. Because temperate wetlands are so loud we logically suspect that more sunlight reaches here in a single day than at the Earth’s Equator — and this is true. If you already know how loud you want your sound design to be, then be sure to place the setting at the right latitude and time of year to remain authentic.
WATER
Understanding the importance of water is key. After all, these places are called wetlands. Is your selected wetland area large or small? This will determine if other habitat sounds will be present and the impact of wind and the resulting lapping of water along its shore. Is your wetland positioned at high or low elevation? This will effect biological diversity and temperature fluctuations.
Logically, wetlands occupy the lowest topography in a local area with limited drainage. Some wetlands are ephemeral, filled by snow melt or spring rains, but eventually drying up as the water source diminishes. Some wetlands are perennial, receiving enough fresh water from rainfall runoff, rivers, or underground springs to maintain year round surface water, though, these areas, too, will likely have a fluctuating shoreline as flow rates vary.
Whether ephemeral or perennial, standing water provides unique acoustic properties that an astute designer will want to contemplate fully to ensure a truly outstanding finished program.
When the water is cool, calm, and lies beneath a warm atmosphere, a common condition during early spring mornings, any sound created at or near the water’s surface at first begins to behave like any sound event — the sound waves expand out in all directions. But then something unique happens. As the sound wave reaches into the warmer air layers, it increases its speed (the speed of sound is temperature dependent), and as it does, it bends back down toward the water, reflects off the surface, and repeats the cycle. In the end, the sound propagates laterally with far less loss in signal strength than other landscapes. Large wetland areas are heard clearly — echoes hover faintly, providing a mysterious hyper-reality. Excellent sound propagation means excellent message sending and signal detection.
Think of your wetland under these conditions as both listening and speaking. The edge is where many shorebirds nest and frogs hide. The movement of animals in shoreline waters creates small ripples, sometimes too slight to make a sound, but these vibrations can be seen in the movement of plants and felt against an animal’s floating or half submerged body. For the native animals, this tactile information complements audible information and makes wetland edges more secure places to rest, sleep, nest, and feed than other habitats.
You will want an arsenal of water sounds from ripples to crashing waves to feed your design’s need for water presence. To help meet this need, a variety of water sounds await in Quiet Planet’s Waves, Flowing Water, and Wetlands. It is important to note that there is a distinct difference between the water sounds of wetlands and oceans. Even the calmest seas have relatively long intervals between water laps and waves (wave period) as the result of the size of the water body, whereas, even the largest lakes in the world have shorter wave periods than oceans, and sound, even under calm conditions, to be quick and choppy. Be sure not to use salt water sounds when selecting files for wetlands. Stick with water sounds that have indeed been recorded in true freshwater wetlands.
AUDITORY HORIZON
We know that immediately above the water’s surface is a layer under calm atmospheric conditions that is particularly conducive to sound propagation. It is not uncommon that the entire wetland area, even when miles in diameter, is within hearing range. The distance to the furthest sound audible is called the auditory horizon. If you can hear sounds coming from five miles away, this produces and audible area equal to five times pi squared, or more than 78 square miles. Recently, while listening at Lake Tahoe, Nevada, I heard California road traffic 12 miles away with my naked ears. This auditory horizon in theory produced a listening area of more than 450 square miles, but in practice, because I adjoined a mountainous coniferous forest, my audible semi-circle realistically covered about half as much terrain. At that same location, but under windy conditions, which produce poor sound propagation and include the sound of wind generated waves, my listening horizon fell to less than a half mile away and my audible semi-circle shrank to less than half a square mile.
As the auditory horizon goes through its daily cycle of expansion and contraction you need to consider the sounds of adjacent habitats entering into your wetlands soundscape. To do so, we will once again work with soundscape pyramids, but in a new way.
SOUNDSCAPE PYRAMIDS
Soundscape pyramids were first introduced in Sound Designing Tropical Forests and again in Sound Designing Deciduous Forests. We use this tool to manage designs of more complex habitats. But unlike Tropical Forests and Deciduous Forests, we now need to use multiple soundscape pyramids to consider adjoining habitats that become audible during the expansion of our wetland acoustic horizon.
To demonstrate multiple soundscape pyramids, let’s select a typical lake in the potholes region of North America. Our lake formed ten thousand years ago when the continental ice sheet retreated and left heavy, extremely large chunks of ice behind. The weight formed depressions and the melting ice filled them, creating today’s pothole wetland. This is the template soundscape pyramid for our pothole lake:
We will leave our pyramid unspecified for now while we expand our sonic reality to include other areas that may be out of sight but are not out of earshot due to the large auditory horizon of wetlands. In the Potholes Region such lakes commonly abut grasslands, which burn from lightening strikes every few years, preventing forests from taking root. But our lake serves as a firebreak, so on its leeward side we will have a deciduous forest. This is now a complex soundscape which requires a complex model.
We can see all three habitats represented (wetlands, grasslands, deciduous forest), and the large auditory horizon indicated by the red dotted circle enclosing the three pyramids.
We are ready to begin. First we want to modify each pyramid to more accurately reflect the respective ecological communities. We will delete some classes and modify a few others. Frogs and toads will be removed from prairies. Frogs will be removed from deciduous forests, but toads will remain, and so forth, until each pyramid reflects its actual demographics. We will now pick a couple of scenarios to show how this tool works.
We can see that mid-day conditions have shrunk the auditory horizon so we only hear the sounds of the pothole lake wetlands. We also see that we hear wind (the reason the auditory horizon has shrunk), the waves (produced by the wind), birds, frogs and/or toads, and plants (windblown). The total volume level of all sounds is relatively high (loud). Our model does express what is active and what is not and facilitates the management of the mid-day sound design, but does not help us decide how much each sound category will dominate the overall soundscape. Your experience as a field recordist will guide you the rest of the way. So if you are a sound designer without field recording experience, wetlands offer the perfect excuse to leap into the fascinating world of nature sound recording. Sound recording heightens listening, as well as hearing, and teaches us how to become better sonic observers.
Experience tells me the wind is strong, sometimes surging and blustery, creating quick water laps. Birds give windblown calls of poor clarity. Probably only a few impatient frogs are croaking, insects are weakly audible (not airborne) and plants (reed wind) are dominant at the water’s edge and fading towards the center of the lake. All in all, this is a circumstance of low acoustic information transfer, when resident animals depend on sight more than sound. In other words, a good time for hawks to go on the hunt for any careless prey that might be sunning themselves. Let’s now move to late evening at the same location on the same day, late enough that the wind has stopped, and explore how the sonic reality has changed.
The auditory horizon has expanded (because wind is now absent and has been for some time) to include all three habitats. We don’t know just how far away the auditory horizon is or the clarity of the sounds coming from far away. For this, we rely again on our experience. Front and center we look at our wetlands and hear waves remaining from earlier winds. Birds are still active (evening light), frogs are active and possibly a few toads, and insects (airborne now because they can fly without getting blown away). In the background we hear mostly the grassland with insects (faint indication of crickets but not really identifiable because high frequencies don’t travel far), some of the loudest birds with most distinctive songs (like the meadowlark), and since mammals are indicated, let’s use a distant coyote chorus, perhaps a call to an early dinner at these very same wetlands. Also in the background but at a much lower level (farther away), is our deciduous forest with a few trills of toads and hoots of an owl (ambient light diminishes earlier in wooded areas compared to the open areas of grassland and wetlands, so the relative time is effectively later in the forest).
Now we return to our Master level at Pothole Lake and see that it is set at mid-way, not as high in decibels as mid-day. But there’s a lot more going on, and more importantly, the fidelity is much higher, making the sounds seem louder because they are more intelligible.
In this way we can manage nearly every complex sound design to simulate different seasons, times of day, or weather… Note, however, that soundscape pyramids and complexes of sound pyramids are only management tools. The real artistry comes from experience, experience gained by field recording (read How to Record Wetlands) and by careful observation.
PRESENCE
Keep in mind that even “silent” wetlands are never really silent. There will always be a sense of presence which will be conveyed by sound not sight. Winter or night, when we think silence would be suitable, think long and hard. Selecting one natural silence over another, we quickly learn that no two are the same — although we can’t exactly tell why. Turning up the volume on a “silent” recording to hear all the clicks, snaps, distant murmurings of faraway flowing water or ridge top breezes doesn’t help, because the audibility of different frequencies will shift, creating an entirely new experience. In conveying quiet, you must judge the selection of natural silence intuitively. Just feel it, trust what you feel, and go with it — that is your art.
Soon Quiet Planet will publish Quietudes and Silences for a wide selection of presences, all classified by habitat.
FAINT SOUNDS
Faint sounds are more important than loud sounds when it comes to wetland sound design due to the presence of dynamic auditory horizons. This is counterintuitive to modern life, where the squeaky wheel gets the grease and TV commercials just seem to be getting louder and louder. Wildlife know the value of new information, even faint sounds, as soon as it arrives. Even sounds at the threshold of a species’ hearing offer important clues of events that may foretell the future.
Once you think you’ve finished your sound design, review the entire design and check to see if enough faint sounds are present. This area of sound design is hugely overlooked and yet, when it comes to authentic design it is the most important. Faint sounds in your sound design are like fresh spices in a gourmet meal, which add layers of depth to the experience and make it much more satisfying.
SUMMARY
In wetlands we can design life to its fullest celebration, but with difficulty, because the soundscape is so fragile and easily broken. Follow a sequence of design steps, assessing sunlight, water, and auditory horizon. Use complex soundscape pyramids to manage your design and tap your experience as a field recordist to tweak it. Water sounds will always have a presence. Remember, too, that faint sounds are more important than loud sounds when it comes to satisfying the cravings of your audience for a rich sonic experience. Wetlands provide the all too rare opportunity for your audience to tune in, let go, trust.
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If you haven’t done it yet, you should definitely listen to the WETLANDS audio preview here!