You might have a good idea from reading, and your knowledge of forested areas.. where potential areas to investigate closer to home, might possibly be. I learned about audio surveillance, from others out investigating, and the valuable results this can provide. I was also familiar with this method, by doing nature recording. All that is required is to leave a recorder out in these areas, and to monitor the results. You will probably hear more strange sounds, than anything else, while being involved in this research and investigation.
Any audio recorder will do, but there are some that have more extended battery life, more field durable, and produce lower self noise for picking out faint sounds in a recording. To get into more details about recorders, there are many using them on our forum, that can recommend and guide you to making a good purchase.
If you are camping out at the same locale, I recommend that the recorder be placed well away from camp. It makes sense, that any creatures in the area might sound off naturally, when a human presence is not nearby.. but this might not be true in every case. No one knows, for sure.. exactly what patterns these creatures follow, and how and why they do the things (and make the sounds) they have been reported to do, by witnesses. That is why I also keep a recorder in camp, and bring it into my tent, and set up a camp surveillance, while sleeping. Squatch has been know, to visit campsites. Some might be curious, while others might keep their distance away from humans that enter their areas. There is little doubt in my mind, that they know what we are doing, from the moment we enter the area... if they are present in the locale. For some reason, audio recorders seem to have better results, than camera traps.
I prefer to bungee my recorder to a tree, or set it in a large tree crotch. I use a small plastic tripod, or a little gorilla pod, with the bendable legs for adjustment. When I use external mics with the recorder, they are clipped to the bungee, on each side of a tree. I try and select a tree that is about human head width, to simulate a decent stereo effect and human hearing. I document when the recorder is set out, and when it is retrieved. I note what direction each mic (left or right channel), is facing. Omnidirectional mics work the best, and give you the greatest area of coverage. A good quality set of binuaral mics, that are field worthy, will do the trick for external mics. Many digital recorders, have omnidirectional mics built right in.
I have heard about bipedal sounding footfalls being heard approaching the recorders, and have heard this in other researcher's recordings. I have recorded an unexplained "something" approach my recorder, and scratch, poke , and possibly lick at the fake fur mic cover on the recorder. The most difficult thing about audio, is that there is no visual. The sounds are classed as "unknown", until they can be documented and absolutely explained for a source. This... I will not hesitate to say, is the most difficult part. It often leaves the listener.. with more questions, than answers. It does, however... let one know that interesting and unusual things are happening around the area, and makes it absolutely worthy of further investigation. For this reason alone.. it makes the recording venture well worth the effort. If nothing is noted (besides expected known wildlife sounds) after several tries, than it's time to move on to another area.
For longer term recording, there are solutions such as bringing a 12V battery along, and stepping down the voltage to meet the power needs of your recorder, with a DC to DC converter. This setup, includes a waterproof pack / case and rain cover for the recorder, battery, and converter, and camo netting to conceal the setup from other people finding it, in my absence. The mics are clipped to a bungee, and are the only things exposed. I use the largest SD memory storage card, the recorder will allow. This has given me about a week of continuous recording. I know of others, that are even getting more continuous run / recording time, in the field.
The most time consuming and sometimes boring part of all this.. is monitoring the results. I download the audio from my recorder, to my computer. It helps to own a recorder, that is user friendly, for doing this task. Many choose to look for peaks in the audio WAV graph, while others look at the recording in spectral form, that can show even more detail. Personally, I listen to the whole recording, in sections.. while viewing it both in WAV and spectral forms. I want to listen to everything recorded, because many sounds are faint (and show no apparent peaks), and are sometimes lost in the flat line , of the visual data.
This can takes weeks (as time allows me) of careful listening, with good quality headphones on, at as high of a volume that I am comfortable with, to review just a weekend of audio data. If something of interest is found, I note the labeled segment of the recording, and then clip it out, rename it, and make it a separate file from the original longer master recording. From there, I will sometimes amplify the sounds of interest, and even try for subtle noise reductions , if any hiss is present after the sound if amplified. There is a wide range of software programs to use for this, and also a very good freeware (Audacity) program available for the computer.
What sounds have I found ? Knocks that sound like wood on wood, from the middle of the night. Softer knocks that sound like tapping, or even metallic sounding. Sounds that are percussion - like, that sound like wind chimes and bongos. Knocks that are in the company of strange vocals.. that sound owl- like. Most common, is a human sounding "yaaahoo" or "ahhhoooo" or "wooooooo", or "ohwoooo", recorded both in NY, and in Pennsylvania. Also, a whistle - like vocal that sounds quite loud, and more like a vocalization . Most of these sounds were recorded in the earlier AM, or late PM, and in areas where human presence was unlikely, but not impossible. Another sound to look for, would be high pitched siren like screams, and howls.. that sometimes mix in with canine howls.
Once I have recorded the sounds of interest, I try and compare them to what others have recorded. I've found some startling comparisons, to what others have recorded, in other states, as well as my home state of NY.
Here are a few examples, of some of these clipped out recorded sounds from NY state:
http://soundcloud.com/imonacan/ooooohooh-edit
http://soundcloud.com/imonacan/ovrnght-10-11-clip-vocalizations-knocks
http://soundcloud.com/imonacan/set-of-4-tap-knocks-2
http://soundcloud.com/imonacan/wood-tap-knock
http://soundcloud.com/imonacan/ovrnght-8-1-pt1-clipe
A couple clips from Pennsylvania, that were possibly in response to my own vocal:
http://soundcloud.com/imonacan/my-whoop-with-possible-distant-replies
http://soundcloud.com/imonacan/amplified-possible-distant-replies (the above sounds of interest, that were amplified)
http://soundcloud.com/imonacan/distant-knock
All of the clips, were found and clipped out of longer (overnight / surveillance) recordings.
These sounds, may or may not be sasquatch related... but they have held my interest, and encourage me to keep on investigating in those areas.
What do you think they are?
I encourage you to give this recording venture a try, yourself. Use audio surveillance to your advantage, and listen.. for what you might also come up with in your own field recordings.
Bill
