Audio Examples & Research using Vibrating Transducers in Metal

A number of my works utilize Vibrating Transducers, including Big Wave Sound and The Musical Barrels. Here are some samples of how audio sounds when it is played through vibrating transducers mounted to sheet metal. Although I experiment with different types and shapes of metal which varies the tones and resonances of the sounds, the basic premise can be understood by listening to the samples below. The audio that you hear below is not in any way filtered before it is sent to the transducers. You can read a little bit more about them below (filtering) as well as an outline of our sound design.

LittleWing Metal by sletiman

Whales Metal by sletiman

Fruits_Metal by sletiman

JohnHenry Metal by sletiman

Rebirth Metal by sletiman

Brownstone Metal by sletiman

Sound Design

There are a number of audio possibilities but they can be roughly broken into four categories:
1) Pre-recorded compositions. Collaborators working with this project will be invited to compose pieces for the sculpture. The compositions can range from ambient background music to more demanding pieces that challenge the acoustic possibilities of the structure.
2) Live audio. Inside the structure there will be audio inputs allowing musicians and DJ’s to plug microphones and instruments into the system and project their performances throughout the entire structure.
3) Amplification of the surrounding audio environment. Parabolic microphones will be placed at various distances around the structure to will gather audio and send it into the wave tunnel. This will essentially channel the surrounding audio in the same way that a wave can be said to channel the energy of the ocean.
4) Environmental recordings or live transmissions of particular natural environments. For a number of years, researchers at Stanford University’s Center for Computer Research in Music and Acoustics (CCRMA) have been using high-speed, high-bandwidth networks to connect performers in different locations for a shared musical experience. The work that they have been doing could be applied to sending audio from natural marine and underwater environments into the wave. For example a hydrophone placed in Monterey Bay could send streaming, multi-channel audio into the tunnel of the wave while microphones on the shore could be sending audio to the sloping wall of the wave.

Filtering

The mathematical models that apply to ocean surface behavior are the same fundamental building blocks that can be used to explain the audio feedback loops that are used in sound synthesis. The non- linearities of both systems are what create their rich and dynamic behavior.

In fact, dealing with the non-linearity potential of the sheet-metal membrane is one of the more exciting research aspects of this project. When two vibrating transducers are attached to a piece of sheet-metal curved into a half cylinder, the result is an immediately haunting sound with most of the original audio from the sound source in tact and audible but enough reverberation and mutual interference to createeffects reminiscent of the Plate Reverberation systems that were heavily used in audio recording during the 1960s (Phil Specter, the Beatles, Motown). This material reverberation effect coupled with the reverberant acoustics of what essentially becomes a speaker that has been physically bent into a parabola shape, creates a unique sound that is both arresting and potentially unstable. While this audio effect is interesting, it is even more exciting and sonically inspiring when it can be controlled and employed intentionally depending on the sound design objectives. Using digital signal processing techniques such as phase shifting, all-pass filtering, de- tuning and compression, we are able to get a sound that is considerably more like what you would hear coming from your home stereo system. Using these synthesis techniques, we will be able to play with how much we allow the chaos of this audio system to take over the acoustic sphere and how much we try to temper the complex reverberation and interference patterns that the sculpture’s shape and material create.