A site dedicated to the review and analysis of potential sasquatch vocalizations, Sasquatch Bioacoustic combines techniques from the domains of intelligence collection, audio analysis and bioacoustic studies to examine the evidence of sasquatch through their vocalizations. ~Monongahela

Sunday, January 8, 2012

The New Howl - A Demonstration of Sasquatch Vocal Range and Lingual Dexterity

On various websites around the Internet witness reports have described loud vocalizations that were initially mistaken for a siren due to the sheer volume and tone of the call. But as the vocals played out, most witnesses come to realize they are listening to an organic sound, and not something mechanically generated. Until recently, few recordings existed to demonstrate that characteristic however, beyond those of John Andrews and Darrold Smith. Fortunately, some new examples of "horn-like" or siren-like vocals are being captured around the country in such diverse locations as Washington, West Virginia, Kentucky, Virginia and Mississippi.

This amazing clip of a loud vocalizer was captured by "Jolie" at 3:41 a.m. on February 10, 2009, outside of Hattiesburg, Mississippi. To protect Jolie's privacy we are leaving out her last name. To the casual listener the clip sounds like a bizarre mechanical cacophony, almost like hydraulic machinery under stress. But when we put on the head phones, pay close attention, and scrutinize the spectrogram of this recording, several telltale characteristics emerge including falsetto notes, abrupt pitch changes, attenuated fundamental frequencies and integrated wood knocks.

The metallic sounds of the higher notes in this clip have a brassy tone, almost horn-like. This unique call is difficult for humans to replicate organically and is not commonly known to be produced by other North American mammals. The evidence that sasquatch are capable of such uniquely cryptic vocals are another intriguing element of study in the realm of this poorly understood creature.

This is not the first time these mechanical/metallic tones have been captured, but this is one of the clearest examples that also contains other important sasquatch indicators. It is recordings such as this that help us understand descriptions from witnesses, such as the metallic "ping" vocal reported in this BFRO report: "Hunter remembers his lengthy daylight sighting through binoculars near Dora". With time, more of these vocals will emerge and be added to the growing lexicon of sasquatch vocalizations.

Thursday, January 5, 2012

Post-Processing Audio Files with Audacity

Almost two years ago I wrote a post titled "Using Audacity to Get The Most Out of Your Recordings" with the intent of passing along useful information to other audio researchers interested in getting the most from their field recordings. In the time since that post I've refined my techniques and modified a few of the approaches I previously described. So it seems appropriate to revisit that old material and update it with some of the newer tricks I use while post-processing the audio files I've captured.


Over the last few years I've had the opportunity to review a lot of "wild life" audio which normally involves digital recorders used to capture sounds over great distances. Often these recordings produce faint, noisy results that to the untrained ear possess nothing of interest. But after some looking around and a little practice, I've learned some techniques that work for amplifying weak sounds while filtering out noise to improve audibility. This has allowed me to go back and review hours of recordings that I thought were basically empty, only to discover an amazing amount of very interesting audio. This has proven so useful that I thought it worth while to pass along this information to anyone else who may want to give it a try. So here's my approach to post-processing my recordings using Audacity.

First, here's what you'll need: the free audio editing program Audacity (download from: , get the 1.3.x beta, it's stable and has the features needed for this work); a reasonably good computer (probably the one you're using now will be fine, I used a five year old laptop for most of my efforts); and a good pair of headphones (over the ear type are best, you don't want stray noise getting in the way).

The rest of this post assumes you have isolated short segments of interesting audio worth post-processing. The processes described below may not work very well on exceedingly long audio clips. If you are starting out with a large audio file and need to review it for sounds of interest, I recommend you begin with this post about using Audacity to review large audio files.


After installing Audacity, here's the process I use to first amplify, then high and low pass filter, and then noise filter a recording for best results.

-Open the audio file you wish to edit in Audacity and it will be displayed as a waveform in its own window.
-Go to the "Effect" menu, open it, then select "Amplify". The entire audio waveform will be highlighted and a window will pop up

-In the Amplify window it will provide a default Amplification(dB) and a New Peak Amplitude(dB). Normally it will automatically choose the amplification needed to achieve a new dB level of 0.0. This is often good enough for our purposes, and you can just click "OK" and be done.
-On occasion you may wish to use a higher amplification setting, which will cause "clipping" of the loudest sounds in your file. There are times when this is desirable (e.g. to over ride loud clicks in the foreground), and checking the block to "allow clipping" will force this over ride.
-Also note the "Preview" button. This allows you to test the results of the settings you've entered before committing changes to the file.Click it to see if you like what you hear.
-Finally, click OK and the whole audio file will be amplified.

The next thing I do is apply a couple of filters to minimize noise in higher and lower frequency ranges.

The first step is to apply a "Low Pass Filter".
-Go back to the Effect menu, open it, look toward the bottom and click on the Low Pass Filter.
-In the resulting "Low Pass Filter" window the settings I use most often are as follows:
-36 for the "Rolloff (dB per octave)" setting
-the default (0.7) for the "Filter quality" setting
-and 1750 for the "Cutoff Frequency (Hz)".

After making these settings, click OK and the frequencies above 1750 hertz will be continually reduced in volume by 36 decibels for every octave above 1750. The result is a recording with much of the high end hiss minimized (allowing everything below the 1750 frequency to "pass" unmodified".

Next use the High Pass Filter to minimize low end rumble and wind noise.
-Return to the Effect menu, open it, look toward the bottom and click on the High Pass Filter.
-In the resulting "High Pass Filter" window the settings I use are:
-36 for the "Rolloff (dB per octave)" setting
-the default (0.7) for the "Filter quality" setting
-and 315 for the "Cutoff Frequency (Hz)".

With these settings in plave, click OK and the frequencies below 315 hertz will be diminished by 36 dB, for each octave blow 315 Hz.

(Before discussing Audacity's Noise Removal tool, let me suggest that if you have access to Adobe Audition, even an older version like 3.0, it's Noise Removal tool offers far better results than anything I've been able to achieve with Audacity.)

Next, we want to use Audacity's "Noise Removal" tool.

-First, click the little icon at the top of Audacity that shows a magnifying glass with a plus symbol in it. This will zoom you in one step for each time you click it.
-Zoom in until you can see the individual seconds of your recording, left to right across the top of the spectrum window.

Look for a section in your recording that has the "noise" you want to remove, but contains none of the faint background sounds that you want to keep. It takes practice, but you'll be able to spot these areas eventually; they're normally the flattest part of the recording's spectrum.

Once you've found that quiet, white noise spot in your recording, use your mouse to click and drag across a couple of seconds of the white noise. This highlights a short segment of your file and defines an example of the noise signature to be removed by the Noise Removal tool.

-Now, go to the Effect menu again and from there select the "Noise Removal" tool. A little window will pop up and at the top, in "Step 1" you'll see a button labeled "Get Noise Profile".
-Click it, and the noise sample will be captured.

-Next, on your keyboard, hold down the "ctrl" key and hit the "A" key (Ctrl-A for short). This will select the entire audio file again.
-Now go back to the Effect menu and select the Noise Removal tool a second time.

In the Noise Removal tool section labeled "step 2" there are five settings you can adjust. For starters, try using these settings:
-Noise reduction(dB): 12
-Sensitivity(dB): 0.0
-Frequency smoothing (Hz): 150
-Attack/decay time (secs): 0.15
-Noise - Remove (radio button selection)

The Noise Reduction number is where you get the most bang for the buck. If it's a fairly quiet file you're working with, then a setting of 6 might be fine. If it's a very noisy file, you might try 12, 18, or even more. But be sure to use the "Preview" button in the lower left corner to see what your result will sound like. If you have the Noise Reduction number set too high, your result will have a "tinny" or metallic sound that is worse than the original noise. You want to select a number low enough to minimize that metallic sound, and high enough to minimize the noise in your recording.

-Click OK and the noise will be filtered from your file.

By this point, the Noise Filter, Low and High Pass Filters have probably knocked the overall volume level of your recording down a bit. So, as a last step, it might be advisable to re-perform the "Amplify" step described above. This should bring the recording level back up to 0.0 dB and make it suitable for basic listening on computer speakers.

Note that we haven't saved our work at any point in this process. Now might be a good time to to do so. But instead of saving it, you'll want to export it.
-Do this by selecting the "File" menu and then clicking on "Export".
-A box will pop up where you can enter a new file name (a good idea so that you don't over write the original file).
-Type in a new name and then hit OK.

As with anything, a little experimentation might improve your results. So feel free to play with the settings discussed above. But for a quick start to getting the most out of your audio files, these suggestions should work for most people.

Now you're done. You have an amplified sound file, with noise effectively reduced, and extraneous low and high end frequencies tamped down to improve audibility. It's time to give the file a play back through your head phones. Turn the volume up to a comfortable setting and you should be amazed at how much better the original audio sounds, and how many faint or previously inaudible sounds you can now hear clearly.