The eight sound presets
| Preset | Character | Notes |
|---|---|---|
| Sine | Pure carrier tone | Classic EMDR default. The cleanest, most neutral sound — what in-office EMDR hardware kits (EMDR Kit, NeuroTek) produce. |
| Triangle | Softer than sine | A warmer harmonic content than sine; less sterile feel without losing clarity. |
| Soft drum | Subtle thump | EMDR 2.0 default. Sine carrier with a fast envelope shaping — a percussive but gentle texture. |
| Chime | Bell-like decay | Triangle waveform with a slower envelope; a tone that lingers slightly between pans. |
| Click | Very short ping | A sharp attack with minimal sustain — closest to the in-office BLS device “click.” |
| Woodblock | Percussive | Square waveform with a fast envelope; firmer than soft drum. |
| Alpha drum | Meditative pulse | Low triangle with a slow envelope; a deeper, more grounding texture. |
| Tick | Metronome-tight click | Sawtooth waveform with an ultra-fast envelope; precision feel. |
Carrier frequency
The frequency slider is set to 250 Hz by default and clamped to 200 to 450 Hz. This is the pitch of the carrier tone underneath whatever preset you’ve chosen. Most clients tolerate the 200–300 Hz range well — high enough to be clearly audible without being shrill, low enough to feel grounded. Move higher (350–450 Hz) for clients who prefer a brighter feel; move lower for clients who report the higher range as fatiguing.Pan rate
The audio pans hard left to right at the samespeed_hz value as the
visual stimulus. If you set the rate to 1.5 Hz, the tone pans left↔right at
1.5 cycles per second. Visual and audio always stay phase-locked.
Hard panning is intentional. This is not binaural beats — binaural beats
use two slightly detuned tones in different ears and are a different
mechanism (entrainment) not validated for EMDR. Rivet’s audio modality is
straight stereo panning of a single tone, matching the in-office BLS
hardware convention.
Volume
A 0 to 100% slider. The default is 60%. The client’s device volume sits on top of this — a 60% Rivet volume with the client’s phone muted produces no sound. If the client reports they can’t hear the audio, ask them to check their device volume first.How the audio is built
A continuous oscillator drives the chosen waveform. An envelope shapes the percussive character of each preset (sharp attack for click and tick, slower decay for chime and alpha drum). A stereo panner alternates between full-left and full-right at the configured rate. A carrier gain holds the volume.iOS Safari handling
iOS Safari blocks audio playback until the user makes a gesture. Rivet sets up the audio at the moment the client taps Join — granting camera and mic permission counts as the gesture — so audio just works when BLS starts. This was historically the #1 BLS support category across the industry. Rivet sidesteps it by setting up the audio at the moment the client taps Join, not when BLS starts.Audio teardown
When the call ends — peer leaves, session ends, network drop — the audio fully stops on the client. Nothing keeps playing in the background. This prevents post-session audio bleed-through — the failure mode where the tone keeps playing on the client’s device after the call ended.Headphones vs speakers
For optimal BLS, the client should use stereo headphones. Earbuds work. Laptop speakers technically work but the L↔R panning is far less distinct when both speakers are 6 inches apart, and phone speakers (single mono output) lose the bilateral effect entirely. In your reminder email or pre-session message, suggest the client have headphones or earbuds ready. See Best practices for virtual EMDR.Related articles
Visual bilateral stimulation
The visual modality — stimulus shapes, motion paths, and the 0.3 to
2.0 Hz speed range.
Best practices for virtual EMDR
Headphones, browser window, client environment, and choosing modalities
for a given client.
Setting up an EMDR session
The Configure modal walkthrough — including the modality picker and
sound preset row.