Audio Archive


This archive contains examples of sounds that are most prominent in the Best Woods soundscape, as well as others that have notable value.  The majority of the audio was recorded from the SM2+ that was stationed 24hr/day in Best Woods. However, some of the samples were recorded with a high quality Rode NT4 stereo microphone and Oade Brothers Modified Marantz recorder.  For optimal auditory comprehension, headphones or external speakers are recommended.  The audio is accompanied by associated spectrograms that can be enhanced and viewed simultaneously while listening to the sounds.

Reading Spectrograms

Spectrograms visually represent sound frequencies.  The sound an entity produces resides within a frequency range, and this is demonstrated on spectrograms.  The Y-axis displays frequency, while the X-axis is time.  The red-orange color is the sound, while the blue-purple background represents the frequencies not occupied by any sound at that moment.  The brighter the red-orange color, the greater the intensity and sound pressure levels.

Click spectrograms to enhance:





Coyote vocalizations in early evening.  In most of these coyote samples, notice how one coyote usually howls first, then two join in, finally the remainder of the group follows.  They seem to form a chorus, with individual vocal parts.  Additionally,  the  vocalization patterns in each circumstance are similar, as if they are rehearsing the same song.


Coyotes 1



Coyote vocalizations in early morning.



Coyotes 2



Coyote vocalizations in early morning.



Coyotes 3



Coyote vocalizations in early morning.



Barred Owl

Unknown Avian



Barred Owl scream from early morning; likely a female.



Bard Owl 1



Barred Owl from early morning with the distinctive “Who cooks for you?” call; likely a female.





Dawn Chorus

Cowling Fields


Cricket Variation



Crickets are sporadically heard in this sample.  It is interesting to note the precise frequency, or acoustic niche, of their sound: 2,390Hz.



Bird and Cricket


Multiple niches are apparent in this example.  The consistent line represents crickets, and they are surrounded by bird vocalizations right underneath the cricket on the spectrogram and the stronger vertical lines above.  Additionally, squirrel chirps are audible and indicated by the striated vertical lines.  Finally, anthropogenic sounds from the road and the unknown building motor are audible and visible as the bright band on the bottom of the spectrogram.  These human-generated sounds do not mask the biophonic sounds because they do not overlap and cover the animal vocalizations.






A good demonstration of typical Red Squirrel chatter.  As indicated by the soundscape Data, squirrels were the most dominant biophonic sound in Best Woods (Graph).  When performing audibility analysis, this squirrel vocalization pattern is frequently heard.


Squirrel Variation


Two types of squirrel vocalizations are apparent here: chips and chatter.  The chirps are the long and brightly colored striations on the spectrogram whereas the chatter is the numerous vertical lines behind the chirps.  The chatter originates from a squirrel farther away from the recorder than the squirrel making the less sporadic chirps.  The ability to hear and see both types of  vocalization is revealing of the variety and complexity apparent in Best Woods.


Squirrel Chewing


When I was in Denali, Davyd Betchkal told me stories, and I heard audio examples, of Grizzly Bears attacking his recording gear.  They mauled the gear and dragged it along the ground before the audio cut out.  While I did not have bear attacks on the SM2+ in Best Woods, the squirrels were ferocious.  At least eight times they attacked the bunny-ear microphones.  Each time they completely devoured the windscreens.  Perhaps they saw the microphones as a threat.  Or, perhaps the windscreens were a tasty treat compared to acorns!  This audio example is from one of the first squirrel attacks.  For most enjoyment use headphones.  It feels as if your brain is physically being attacked.  






The train that arrives in Northfield is frequently audible in Best Woods.  The tri-tone sound from its horn is visible on the spectrogram.




Loud Prop Plane



As this prop-plane flew over the Arb the sound pressure it exerted increased, indicated by the elevated height and  increased intensity of its sound signature (the red-orange mass) on the spectrogram.



Loud Jet Plane and Niches



This jet plane exerted a fair amount of energy over Best Woods.  Yet, it did not mask the other biophonic sounds since bird, squirrel, and cricket sounds are continuously audible and visible.



Potential Masking


This example reveals how masking could occur and thereby eliminate or reduce the niches.  Squirrels are heard in this sample and a loud jet plane is flying over.  The intensity of the plane is revealed on the spectrogram by the bright low band on the bottom.  If the plane had been lower, it would have exerted more sound pressure and thus this low band would rise up and overlay the vertical striations from the squirrels.  Under this scenario, the squirrels would have been masked and their niche would not be visible.  However, this is not the case, and even though the plane is loud, the variation in the system is still present because the squirrel vocalizations are audible and visible as the plane flys over.

Unknown Hiss



This peculiar hiss occurred out-of-the-blue one morning.  There had been light rain earlier on, but aside from that small amount of precipitation nothing else unusual occurred.  The hiss sounds like sleet.  However, since it began and ended so suddenly, and since there was minimal precipitation hours earlier, sleet seems unlikely.  It is possible the recorder manifested some internal noise; yet, this was the only occurrence of this noise and the SM2+ was remarkably consistent with hardly any signal distortion.  Thus, I doubt this was signal disruption from the recorder.  Perhaps the squirrels were performing a more subdued method of attack on the SM2+.

Building Motor




This motor sound, possibly from a turkey farm just beyond the Arb’s border, ran mostly at night and during the early morning.  Oftentimes, it was the only sound that occupied Best Woods during these hours.


Traveling West

Average Audio: Seasonal Audio Collages Representing the Soundscape of Best Woods.  

These are audio collages of the soundscape in Best Woods during an average day in the associated season.  In all tracks, audio begins at 12am and ends at 12pm.  Ten seconds represents one hour.

* Headphones or loudspeakers are recommended, since the early morning and late evening hours are relatively quiet.

Average Day



Average Fall Season Day – Audio from September, October, and November were combined to produce a representation of the soundscape during the Fall season in Best Woods.






September – Biophonic sounds were abundant during the day.  Compare the numerousness and intensity of natural sounds in this track, to those during October and November – they progressively decrease as the months advance.





October – Biophonic sounds diminished in numerousness and intensity in October.  However, anthropogenic sounds were constant.






November – Biophonic sounds were almost completely absent by November.  Again, anthropogenic sounds remained constant.