All images and data collected as part of the Hudson River Benthic Mapping Project
kindly provided by Dr. Frank O. Nitsche, Lamont-Doherty Earth Observatory of Columbia University.

 

 



h1w046g is the profile used to make the video/visual portion of this piece
  
 
 
 
For the Video/Visual portion of the piece, the profile was taken apart by grey-scale groups, as if individual groups of matter: stone, sediment, sand, mud, etc..; except the matter is more alike in that they are similarly minute in size and fall in somewhat similar patterns. These groups of pixel grains varying from very dark to light grey are animated as if in water, and also as, specs in space, or sound signals falling like sand or sediment, they also move as the river, the Hudson itself, in constant motion and in both directions as estuary meets mountain drainage.


This map shows the other locations of profile data that was used for the sound
  

 
Sub-bottom Profiles/ Tech Details

The profiles and data I used were created with a Chirp system used by
Dr. Frank O. Nitsche of Lamont-Doherty Earth Observatory of Columbia University.

The Frequency Range is 4 kHz - 24 kHz
Samples per ping (signal)1601
Sample rate 0.04 ms (milli sec) or 0.00004 seconds
Signal length of each trace: 0.064 s or 64 ms (1600 * 0.00004)

The entire 64 ms represent 96 m of total travel distance
assuming a sound velocity of 1500 m/s.

The signal is often near zero and is a positive amplitude.
That data is stored as absolute amplitude values.

For more information on Dr. Frank O. Nitschefs research:
http://www.ldeo.columbia.edu/~fnitsche/research/fon_research.html

For more information of Sub-bottom profiling:
http://www.ldeo.columbia.edu/res/pi/Hudson/research/bot_mapping/methods.php
http://www.csc.noaa.gov/benthic/mapping/techniques/sensors/subbottom.htm
http://woodshole.er.usgs.gov/operations/sfmapping/seismic.htm



 


Sounds/ From Data and Recordings to Composition

Programmer, Peter Holler, provided technical assistance by creating a program which takes the ASCII data and converts it into binary data. The program also multiplies the amplitude values to increase the overall signal, and creates a wave (positive and negative values) out of the original absolute amplitude value by assigning an average negative value between adjacent values.

I then dampened the spikes to allow for more of the signal to be heard. I did this in varying degrees, saving each as variations. I also added bandwidth changed time lengths and frequencies to create new sound files. I ran some sound through digital looping with filters, effects, and manipulated them to increase sound character possibilities. And some of the sound files made from data, I left alone, I just looped them or added time. I felt it was important to hear the signals as close to the original as possible.

I also used the expanding sound envelopes to design other sounds. I did this with recordings I made of materials such as sand or glass. The intent was to record sounds that metaphorically had similar characteristics to the actual river bottom materials, like the vide, and also not like the river bottom; I wanted to expand the poetic possibilities for the listener, to open the piece up to a more variable meaning and experience.