A single frequency pulsing on and off at the target rate. Your auditory brainstem responds directly. No stereo separation required — works on speakers, in groups, stacked over binaural.
Binaural beats create a phantom frequency using two slightly different tones in separate ears. Isochronic tones skip the phantom entirely — they are the entrainment signal, delivered directly as a rhythmic amplitude pulse.
A single carrier tone — say 200 Hz — switches on and off rhythmically at the target brainwave frequency. At 10 Hz (alpha), the tone pulses 10 times per second. At 40 Hz, 40 times per second. The auditory brainstem, specifically the inferior colliculus, produces a auditory steady-state response (ASSR) that entrains to the pulse rate.
Because entrainment is in the amplitude — not a stereo phase relationship — it reaches both ears simultaneously. A single speaker produces the same effect as headphones. This makes isochronic tones uniquely valuable for group meditation, speaker-based sessions, and anyone who finds headphones uncomfortable for extended wear.
Left ear: 200 Hz. Right ear: 207.83 Hz. Brain calculates 7.83 Hz phantom. Requires stereo headphones. Works in auditory cortex.
Carrier: 200 Hz pulsing at 7.83 Hz. Works on any playback device. Response in auditory brainstem. Measurable via ASSR.
FrequencyNova implementation: Pulses use a 48% duty cycle — on for 48% of each period, off for 52%. Attack and release times are 4ms: fast enough for sharp entrainment, no clicking artifact. Timing uses a lookahead scheduler — the pulse is calculated 150ms ahead to prevent CPU-load gaps. Activate in the Therapeutic tab. Works on speakers.
EEG studies consistently show the auditory brainstem produces a neural oscillation matching rhythmic sound events — the same frequency-following response underlying binaural entrainment, triggered through amplitude modulation rather than phase difference.
MIT's GENUS protocol uses a 40 Hz isochronic tone — not binaural beats. The clinical trials showing cognitive benefits in Alzheimer's research are based on isochronic stimulation, making 40 Hz the most clinically grounded isochronic application available.
The most important practical advantage: isochronic tones work through any audio output. Group meditation classes, speaker systems, and people who prefer open-ear listening can all benefit without headphones. Stack on top of binaural for redundant entrainment.
FrequencyNova generates isochronic tones at any of the six brain state frequencies. Activate in the Therapeutic tab.
Open the Generator