Depending on the purpose for recording soundscapes, various set-ups can be used from recorder boxes left in the woods on timers (for researching species density/diversity and local sounds), to parabolic dishes (isolating distant wildlife calls), to ambiance recordings (capturing realistic sounds for enjoyment or research).
One of my interests is to record the ambiance of a place, as it is heard if one were actually there. To do this, my gear has evolved from using whatever microphones I had laying around the house to experimenting with homemade gear.Without spending a couple thousand dollars on high-quality microphones, the do-it-yourself systems are very comparable and a fraction of the cost. Basically I took what appeared to be important from various sources and created my own systems.
I began to understand what features seemed to create the recordings I was after.As I am still experimenting on how to make the soundscapes better, I like to keep my set-ups fairly adjustable and modifiable for various situations. I now use omni-directional mic capsules (that capture sound from 360 degrees), wired to an external battery pack/circuit.
The capsules I use (EM-172s) have excellent features in low self-noise and hi sensitivity for those quiet nature sounds. To create a recording that mimics a realistic, listening experience, I use two pairs of mics in parallel (to increase sensitivity) that are separated by roughly 5 inches (e.g., headspace). The space between the mics has some kind of dense material to block sounds and create a stereo-like, realistic effect. These systems are plugged into my recorder (Roland R26 or ZoomH4n). I am also able to add my parabolic dish (including one graciously donated by Gray Merriam) to this system to bring-in certain sounds more clearly.
Other microphones are designed to fit into unusual spaces such as cavities in trees, holes in the ground, under water, or clipped to a hat for ease of bi-aural recording while on the go.
More specialized gear, like the recorder below (Songmeter from Wildlife Acoustics) can be left out for a month or more at a time while recording at set times. The Mississippi-Madawaska LandTrust has purchased a few of these to help monitor their properties for current and future research.
Parabolic dishes are pricy but you can make alternatives with decent results. Below is a a dish made from a squirrel guard for bird feeders. Copper pipe, pipe insulator, tape, water pipe fittings and a class jar lid is all that went into this one. A pair of omni directional mic capsules inserted into old gas-line hose for mics were used. In comparison to the tailor made parabolic dish I have (seen above), the sound quality is about 15% less in volume but otherwise fine. That is, the sound I was trying to isolate was not heard as well, even though the actual mic capsules in both dishes are identical.
Below is the new echo metre touch that offers auto-id and specctrogram views of real-time bat calls. The technology is made affordable (relatively) by the use of iPad or iPhone apps. The recordings can be transferred to a computer for further analysis.