The evidence for SAM is thin, and the Institute's own people say so. Atwater's 2012 article is a design rationale that expected objective evidence from later studies of gamma synchrony. In a talk posted in 2018, researcher James Lane said three studies of his looking for relaxation effects had not shown powerful effects. A small pilot using a mystical-experience questionnaire, with 14 participants and no control group, found that seven met the criteria for a complete mystical experience. For now SAM is best understood as a different way of building the sound, backed by design theory and participant reports rather than controlled results. One moving tone instead of two beating tones Classic Hemi-Sync, as A.J. Honeycutt described it in 2014, combines Bob Monroe's voice, a bed of phased pink noise and the Hemi-Sync signals themselves; Focus 10, for example, uses a mix of delta and theta signals. Those signals are binaural beats. Atwater's 2012 article says SAM instead uses a single carrier tone whose apparent position is moved digitally through a stereo field. Because the position changes faster than the brain can track, the listener hears a tremolo, which Atwater calls similar to binaural beating. Five adjustable settings, against two
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The 2012 article counts five design variables for SAM: carrier frequency, modulation frequency, peak phase deviation, and a pair of angular constants that place each movement arc in longitude and latitude. It contrasts them with the two that binaural beats offer, the left and right frequencies. Atwater argues that this lets designers send different movements to different regions and hemispheres, for example one pattern to calm a dominant hemisphere and another to encourage synchrony, and so shape a session more finely than binaural beats can. Built as a complement, not a replacement Atwater wrote that the Institute began investigating a complementary method in 2008, looking for an audio support that would extend the range, scope and flexibility of its seminar programs and educational materials. SAM, he added, would not replace existing Hemi-Sync products or programs but could provide a platform for future ones. He and co-inventor Mike Turner developed it, and in 2013 Bob Holbrook, then listed as the Institute's director of technology, gave a tech talk on the analysis and development of SAM version 2.0. Three stages: disruption, induction, stabilization
Atwater describes a SAM session as a three-stage process adapted from Charles Tart's 1975 model of altered states. First, certain movement arcs disrupt the listener's ordinary baseline state while others point toward the desired one. In induction, state-specific arcs take over. In stabilization, the arcs are adjusted simply to support the new state, and quieting them can be enough to bring the listener back to ordinary waking awareness. He says SAM can be layered with music, nature sounds, pink or brown sound and spoken guidance. A different theory of how it works Atwater wrote that the Institute does not suppose SAM entrains or drives brainwaves the way the binaural-beat model does, and he called the entrainment explanation a logical fallacy. He pointed instead to the brain's arousal system, to coordination between the hemispheres, and to a hypothesis that the tremolo supports quantum coherence in neuronal microtubules, an idea drawn from Penrose and Hameroff and worded in the article as a supposition. These are the developer's hypotheses; the article reports no measurement of any of them. Where listeners meet it