Escape for Soundscapes: Stereo Field Recording
Updated: Nov 7, 2018
A few months ago I took a trip to a far away place where you can be in snow-capped mountains, then drive down the road and you're in the desert, drive a bit further, you're in a tropical rainforest, and a bit further and you're on a Volcano. I traveled to the island of Hawai'i, The Big Island which consists of 11 of Earth's 13 different climates on a small island about the size of Connecticut. This made finding completely different sounds and ambiences very easy.
Of course, there were no volcanic eruptions during my time there and many of the animals known to Hawai'i are either quiet or silent (Sea Turtles aren't known to sing). Hawai'i is amazing for photos but I'm the 1% who says we don't need more of those, rather we need more sound recordings. I like to record ambiences and sound effects because the sound transports you more than a photo can. Photos hold information as sound holds emotion. There is so much more personality and character in the sound than in a photo of something. If you listen to an ambience with your eyes closed, your imagination can easily fill in the visual blanks and likely create something more pleasing than a photo will provide you, see War of the Worlds Radio Broadcast. So, with this, I packed up my sound gear and hopped on a plane to The Big Island of Hawai'i.
Brett Ainslie recording ambient sound on the coast of Hawai'i
There were a few ambiences I wanted to make sure I got; Ocean / Beach, Rainforest, Luau (not sure how I'd use that), and any bubbling lava if possible (no, it wasn't, but one can dream). The most interesting one to me was the rainforest. The south and east sides of the island are filled with rainforest and they are stunning. I've never been in an actual rainforest in my life, so my imagination had presumed certain sounds I'd hear. After some research, some of the sounds I envisioned would come from animals that either are not native to Hawaii, such as monkeys, or these types of animals do not live in the rainforest in Hawai'i, but do in other parts of the world; Peafowl are indeed native in Hawai'i but the Peafowl in Hawai'i do not live in the rainforests, but do in other parts of the world. So, I created a few ambiences here; one is a natural recording of the rainforest in Hawai'i, another is a more jacked up one with some added sounds I recorded separately, either on this trip or another. All sounds were recorded by myself.
How I Did It:
I could have recorded stereo, surround, binaural (360 stationary), ambisonic (360 VR), XY, Mid-Side, AB, or many other combinations. I went with a stereo recording with two microphones for simplicity, both pointed left and right of the source (180 degrees apart) to get a balanced recording. Then, I often recorded another track for a few minutes with one of the microphones directed towards the source for a cleaner, more natural on axis recording of the particular sound, whether it be waves, a bird, etc. My next step was panning it accordingly in post or mixing it with the other recording to complete a version of a M-S setup. The downside of this setup with the two microphones facing complete opposite directions is there is that small gap in the middle that they don't naturally cover. This is why I needed to record most ambiences in different positions, especially since these microphones are particularly direct. I'd rather use two cardioids and angle them 80-110 degrees apart or build a true M-S setup with a third mic. If portability and safety from rain and wind weren't as much of a concern, I'd use this setup, but after my tests, this basic stereo setup worked satisfactorily for my purposes. Most of the atmospheres I was looking for were stationary constant sources such as beach waves, not a specific moving animal such as a tiger, so I was able to get away with needing to record the source for a few additional minutes with intentions of combining in post. Even if the two recordings didn't match, I was able to make them sound natural and in sync by panning slightly to make them spread into each direction, the Left channel, right channel and even in the center.
I placed two Sennheiser microphones, a Sennheiser MKH 416 supercardioid and a Sennheiser MKH 50 hypercardioid into a blimp for wind protection spaced 180 degrees apart. These are both small single diaphragm microphones which are great because they reproduce a wide frequency range and are less likely to be subject to phasing issues than microphones with multiple diaphragms. The 416 was my left track, and the 50 was my right track going into a Zoom H4N. Both Sennheiser microphones, especially the 416 are also great in poor weather conditions, humidity, extreme heat, wind, sand, etc which made me feel confident bringing them into a tropical rainforest, to the desert, on a volcano and to snowy mountains all in the same week. Although next time, I'd like to use a matching pair of microphones, likely cardioid or possibly omnis for longer distance recordings of low frequencies. Or, a more interesting venture would be to dig into a 360 degree system for virtual reality or a surround sound recording system such as the DPA 5100. This is a small, easy plug-and-play high quality surround sound microphone system that is really built for recording atmospheres like this, sports broadcasts and more.
(Left) Sennheiser MKH 416, (Right) Sennheiser MKH 50
I went with the Zoom H4N on this trip over my Sound Devices 664 for portability, safety and recording specs. The Zoom actually records at a higher sampling rate than the 664 (96kHz on Zoom, 48kHz on 664) which is barely noticeable on some recordings but useful in sound effects and ambient recordings to get the finer details of higher frequencies more accurately recorded. I also did not need the quieter preamps from the Sound Devices on this trip or most of its additional features. Although, a SD 633, Mix-Pre 3 or Mix-Pre 6 from Sound Devices would have been nice options as they're smaller than a 664 and record 48, 96 and 192kHz; this would have been helpful when recording bats in Texas and some birds on any of my expeditions. The 664 is really strictly built for dialogue recording.
In the Field
My setup was very portable and well concealed. I was able to carry it in a backpack when not in use, quickly take it out, power it up and hit record when needed. However, in the future, I'd like to be in scenarios where I feel more comfortable bringing a stand, setting it up in a hidden area in my space and walk away. This would be by far the best way to record moving subjects such as animals as they wont want to come near humans; I'd be able to possibly get natural sounds of large wild animals from up close and not get mauled. A parobolic microphone would be a nice tool for these situations as well, capturing animals or sounds at higher frequencies from a distance and making them sound up close. The problem with this is they don't capture low frequencies well at all in regards to gain or accuracy and also require much precision in aiming which can be difficult if you do not see what you are trying to capture. A parabolic microphone isn't for atmospheric recording at all, rather for capturing a specific sound source such as a bird, a private conversation, a lion, or sports sounds.
Since working in live sound and music the last few years as a sound engineer, I've been learning how to create clarity between sound sources by equalizing the frequencies. In a film, for example, we would not want a background "room tone" to interfere with the dialogue. We would want the sounds to stay below the frequency range of dialogue in order to maintain clarity. If this is our goal, omni directional microphones or wide cardioids would be a great microphone choice to ensure we are getting those low frequencies very naturally and with good signal to noise ratio at greater recording distances.
I love experimenting with these techniques and every time I do so, I think to myself, "What will this be used for?". Is it meant to be a stand alone piece of art like music or a photo? Is it meant to be used in film or television as a background atmosphere to tell the audience where we are, what is around us and to blend cuts together? Will this be Surround Sound or 360 or just stereo or even mono? Knowing this before recording is important. I'm not yet sure what my next adventure will be but more will go into the planning and preparation when the time comes. Be sure to check back here and on my SoundCloud as I have more there than have been documented here!
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