Experimental

Narrowcasting Sandbox

Multi-source / multi-sink spatial-audio playground — an exocentric implementation of mute / solo (source-side) and deafen / attend (sink-side) per Cohen, M. (2000) “Exclude and Include for Audio Sources and Sinks.” Presence 9(1).

How to use: Drag any  source or  sink around the stage to relocate it. Each sink shows a  nose marker — drag that to rotate the sink’s head orientation; HRTF spatialization for that sink follows the rotation. Per-source mute / solo and per-sink deafen / attend follow the radio-button idiom from the paper’s Figure 8: any one assertion clears the others in its column (hold Shift to extend the set instead). The dropdown beside each sink “tunes” that sink to a specific source — selecting a source is equivalent to attending just that sink and soloing just that source. The animated particle streams visualize the active source→sink unicasts (Figure 5).

Every sink is treated as self: this is a single user with multiple simultaneous telepresences (the multi-sink presence case of §2.2). The final stereo output at the physical speakers is the binaural superposition of what each sink would hear individually — “sonic cubism” as the paper calls it: being anywhere is better than being everywhere, since it is selective.

Keys (while the pointer is over this figure) — Space play or pause  ·  V cycle the views  ·  C clear every narrowcast  ·  arrows and + / − steer the camera in the 3-D view.
Sources: 1 – 9 0 mute, with Shift to solo.   Sinks: the same digits with ⌥ deafen, and ⌥ + Shift attends.   0 is the tenth channel; ⌥ + C clears just the sinks. (⌥ is Option / Alt. Firefox on Linux keeps ⌥ + digit for its own tabs.)

active(sourcex) = ¬mute(sourcex) ∧ (∃ y solo(sourcey) ⇒ solo(sourcex))  ·  active(sinkx) = ¬deafen(sinkx) ∧ (∃ y attend(sinky) ⇒ attend(sinkx))

Sources

Sinks

Source palette. Three of the music sources are the “Shy” MIDI — written by Michael Frishkopf and included with his kind permission — rendered as three separate stems (percussion, harmony, melody) so they can be spatialised independently. The non-music sources (pink noise, click or tap train) are useful for hearing the HRTF differences across sinks without any musical structure to distract.