interference tone #1 : ratios from Seven Sixths to Eight Sevenths

This piece explores a sonic phenomenon called Tartini Tones or Combination Tones. This phenomenon has discreet physical dimensions but also emerges as psychological effects. You may have heard about this before as eadditional tones that are artificially perceived when two real tones are sounded at the same timef.
I have been investigating several ratios for effective combination tones, searching for a relationship between the physical nature of these tones and the psychological nature of how they are perceived. A certain ratio that I focused on relates to one fourth of the primary tonesf wavelength, with a ratio in between 7/6 and 8/7. When two real tones are sounding within this range at the same time, an additional tone will arise as beating, ring modulation, or a phantom tone.
For Continuous Drift / An Introduction to Work and Energy, I have produced a stereo piece, which consists of five parts:
Part 1, 3, 5: One channel is mostly a constant sound very similar to a single tone, but generated as one of the specific resonances of a glass bottle. The other tone is a sine wave, whose frequency varies as a subtle sweep up-and-down or vice-versa. You can hear the third phantom tone emerge as interference between these sounds.
Part 2, 4: An unstable sound utilizing one of the higher resonances of the glass bottle was recorded in stereo. Single sweeping tones (sine waves) are recorded on each separate channel and mixed with the resonance of the bottle. You can hear the third and even the fourth phantom tones again, as interference between these sounds.
The phantom sound appears differently depending on the location where you are hearing these sounds. You can enjoy the sound variations by moving and walking around the square.
I made this piece based on an interest in a phenomenon that appears on Bird and Person Dyning composed by Alvin Lucier.

minoru sato -m/s 2016

this piece was written for Continuous Drift which is a sound installation that is permanently integrated into Meeting House Square in Dublin, Ireland.