Feel, Not Hear

Decorating Time With Sound

COntact Microphones and their use within sound sourcing

Sound travels through mediums at different rates, and through physical mediums they can travel almost 6000 times faster through some solids. This is due to the molecular structure being close together. This allows sound that would be hard to hear in air to be heard over a great distance through a solid.

So what does this mean for sound sourcing? The acoustics of a sound do not appear when recording with a contact microphone. This allows the sound source to become more dissonant to the sound that is actually being recorded, meaning a wider potential for application.

Within the example above I have taken speech, where a voice actor pressed their chest up to the medium and was asked them to say a few lines. This was then recorded using a contact microphone on the same surface and transformed into the pad above. The sound is then spatialised for 3D headphone use, and works through a 5.1 set up. The higher frequencies produced float around the azimuth plane, whilst the low end frequencies are sent straight forward. The aim being to produce two layers of feeling. The first being a low level of rumble which is then topped with higher frequencies which shift and move such as the waves in the picture.

The first stage of the sound manipulation was the creation of a decent sound. To start this I created a weird sounding robotic voice. This was achieved using multiple layers of the same recording, pitched up and down, with phaser added and bass + treble increases. Compression was then added with reverbs set to wet only. These can be seen in the pictures below.

The next stage was to apply interesting sound diffusion. For this piece I wanted to explore the thematic nature of contact microphones. Sound is being transferred through a solid medium. For me that meant presenting sound in a way which isn’t normal. Currently most sounds are presented in stereo format, so to push the technique further I explored different 3D specialisation methods.

Since I am working within a DAW, and not a video game engine, the tools for completely spatialised audio isn’t as available. Using Ambeo-Orbit, you can place a sound within a sphere using the azimuth plane and elevation. The azimuth deals with the plane that goes from forward, back, left and right and the elevation deals with up, down, left and right. Volume is used for distance.

Using this I was able to focus on placing the sound within this space. To start I used a sine wave automation on the azimuth plane to simulate the sound circling left and right of the listener. Next I EQ cut the highs from a duplicated sample, and placed this on the same plain but below the listener. The original sample also received a low cut, to reduce phasing and interference within the audio.

The desired outcome meant that when listened through either headphones or a surround sound system the sound moves around the listener, as if the space the user is in is warping and bending around them. Below are images reflecting this process.