rixxmixxhell
25-02-2009, 08:55 PM
http://ccrma.stanford.edu/~blackrse/monterey.jpg
Introduction
My beginning research in underwater acoustics last Spring (1997) exposed me to various sources on the topic which were not directly relevant to the musical prerogatives I have wished to achieve. Since the available literature is mostly concerned with applications of sonar, the books I had studied on underwater acoustics--Finn B. Jensen's Computational Ocean Acoustics (1993) and P. C. Etter's Underwater Acoustics Modeling (1996)--dealt primarily with propagation paths of sound sources in the ocean; and though the introductory physics of how sound travels in water is valuable to understand, such knowledge describes nothing about the actual sound itself: i.e. I knew how the sounds moved now, but how did they sound? Since my concern has been with the aural result of sound underwater, I still needed to find sources which could relate to me how water manipulates what is heard of sounds compared to that which is normally heard in air: what transformations do sounds undergo when water is the propagating medium as opposed to air? If I throw my jazz combo into the deep end of a pool, for example, (pending we have oxygen) what's going to happen to our music? or what's going to happen to music that is broadcasted through loudspeakers underwater?
Last quarter, studies in architectural acoustics temporarily avoided my hazy understanding of underwater sound, and I was able to mimic, somewhat, the effect of water on sound without any physical understanding: conversations with my advisor Chris Chafe at CCRMA and readings into F. Richard Moore's Elements of Computer Music (1990) revealed a process by which the acoustics of any particular soundscape could be captured for synthesis on the computer with digital signal processing techniques. One such process of capturing the reverberation quality of a room--room meaning "pool" for our purposes, or any other body of water--entails the convolution of a recorded impulse response of that room with the given sound source. Since this synthesis technique, furthermore, merely involves masking the acoustic soundscape of the recorded impulse response onto a sound file, no scientific understanding of the acoustic soundscape or impulse response is required. The results of this process as applied to a pool environment were somewhat unconvincing and unappealing, however, (let alone computationally inefficient) and I have hoped that a better understanding of underwater sound may allow me to comprehend what is lacking in this convolution process and also to employ better methods.
My research last Spring also introduced me to a unique composer who has already employed water as a medium for musical exploration for many years: French-born electronic music composer Michel Redolfi. A search for "underwater music" in Stanford's library system immediately incited me to set up a listening appointment at the Archive of Recorded Sound to hear Redolfi's 1983 recording, Sonic Waters, which includes hydrophone recordings of original electronic music which he had broadcasted in the ocean off the coast of La Jolla, California and in several university pools for the world's first underwater concerts!!! As I will expound upon later, I actually got in touch with Monsieur Redolfi this quarter, who continues to explore underwater music and currently co-directs the Centre International de Recherche Musicale (CIRM) in Nice, France.
contents:
* hydrophone construction vs. microphone construction
* audible transformations in underwater sound
* how humans hear underwater
My objectives this quarter have been primarily two-fold: (a.) to understand the aural results of playing sounds underwater, and (b.) to understand the fundamental difference in construction between a microphone and its underwater counterpart, the hydrophone. As regards the hydrophone, it was a failed attempt of mine last quarter, for the most part, trying to employ a microphone for underwater recording applications. Merely covering a normal microphone with waterproof material (a balloon, for example) proves altogether ridiculous, as amplifying the signal to even the highest extremes on the DAT recorder will not reveal much of anything--even if you yell into it underwater at close range: obviously there is a reason they had to invent the hydrophone; what this reason is, I wanted to know. With regards to aural results, I have already explained this concern in my introduction. Searching the internet for hydrophones this quarter put me in contact with the International Transducer Corporation (ITC) of Santa Barbara, CA, which proved to be the springboard I needed for my research and sparked a chain of other important contacts.
Continued.....
http://ccrma.stanford.edu/~blackrse/h2o.html
Introduction
My beginning research in underwater acoustics last Spring (1997) exposed me to various sources on the topic which were not directly relevant to the musical prerogatives I have wished to achieve. Since the available literature is mostly concerned with applications of sonar, the books I had studied on underwater acoustics--Finn B. Jensen's Computational Ocean Acoustics (1993) and P. C. Etter's Underwater Acoustics Modeling (1996)--dealt primarily with propagation paths of sound sources in the ocean; and though the introductory physics of how sound travels in water is valuable to understand, such knowledge describes nothing about the actual sound itself: i.e. I knew how the sounds moved now, but how did they sound? Since my concern has been with the aural result of sound underwater, I still needed to find sources which could relate to me how water manipulates what is heard of sounds compared to that which is normally heard in air: what transformations do sounds undergo when water is the propagating medium as opposed to air? If I throw my jazz combo into the deep end of a pool, for example, (pending we have oxygen) what's going to happen to our music? or what's going to happen to music that is broadcasted through loudspeakers underwater?
Last quarter, studies in architectural acoustics temporarily avoided my hazy understanding of underwater sound, and I was able to mimic, somewhat, the effect of water on sound without any physical understanding: conversations with my advisor Chris Chafe at CCRMA and readings into F. Richard Moore's Elements of Computer Music (1990) revealed a process by which the acoustics of any particular soundscape could be captured for synthesis on the computer with digital signal processing techniques. One such process of capturing the reverberation quality of a room--room meaning "pool" for our purposes, or any other body of water--entails the convolution of a recorded impulse response of that room with the given sound source. Since this synthesis technique, furthermore, merely involves masking the acoustic soundscape of the recorded impulse response onto a sound file, no scientific understanding of the acoustic soundscape or impulse response is required. The results of this process as applied to a pool environment were somewhat unconvincing and unappealing, however, (let alone computationally inefficient) and I have hoped that a better understanding of underwater sound may allow me to comprehend what is lacking in this convolution process and also to employ better methods.
My research last Spring also introduced me to a unique composer who has already employed water as a medium for musical exploration for many years: French-born electronic music composer Michel Redolfi. A search for "underwater music" in Stanford's library system immediately incited me to set up a listening appointment at the Archive of Recorded Sound to hear Redolfi's 1983 recording, Sonic Waters, which includes hydrophone recordings of original electronic music which he had broadcasted in the ocean off the coast of La Jolla, California and in several university pools for the world's first underwater concerts!!! As I will expound upon later, I actually got in touch with Monsieur Redolfi this quarter, who continues to explore underwater music and currently co-directs the Centre International de Recherche Musicale (CIRM) in Nice, France.
contents:
* hydrophone construction vs. microphone construction
* audible transformations in underwater sound
* how humans hear underwater
My objectives this quarter have been primarily two-fold: (a.) to understand the aural results of playing sounds underwater, and (b.) to understand the fundamental difference in construction between a microphone and its underwater counterpart, the hydrophone. As regards the hydrophone, it was a failed attempt of mine last quarter, for the most part, trying to employ a microphone for underwater recording applications. Merely covering a normal microphone with waterproof material (a balloon, for example) proves altogether ridiculous, as amplifying the signal to even the highest extremes on the DAT recorder will not reveal much of anything--even if you yell into it underwater at close range: obviously there is a reason they had to invent the hydrophone; what this reason is, I wanted to know. With regards to aural results, I have already explained this concern in my introduction. Searching the internet for hydrophones this quarter put me in contact with the International Transducer Corporation (ITC) of Santa Barbara, CA, which proved to be the springboard I needed for my research and sparked a chain of other important contacts.
Continued.....
http://ccrma.stanford.edu/~blackrse/h2o.html