Binaural, isochronic and monaural beats

Every entrainment product is built on the same idea: play something that repeats at a chosen rate and the auditory system will produce activity that follows it. What separates the methods is where the repetition physically lives.

That sounds like a technicality. It decides whether the audio works on a laptop speaker, whether it survives being mixed to mono, and how strong the resulting signal is.

Isochronic: the beat is in the sound

An isochronic tone is a single pitch whose volume is switched on and off at the beat rate. Want 10 Hz? Pulse the tone ten times a second.

Because the pulsing is a real change in loudness, it is present in the air. A microphone would record it. A speaker reproduces it. Mono playback does not harm it.

It is also the strongest of the three as a driving signal, for an unglamorous reason: amplitude modulation is what the auditory system responds to most reliably. The 40 Hz auditory steady-state response — a sustained, measurable electrical response to a tone modulated at 40 Hz — has been a standard laboratory measurement since 1981. You are not relying on a subtle effect. You are relying on the loudest, best-characterised response in auditory neuroscience.

The cost is character. A hard-edged pulse can read as a tick, which is why the envelope — the shape of each individual pulse — matters so much. A gently-rising bell is a very different listening experience from a square gate at the same rate.

Binaural: the beat is not in the sound at all

Binaural beats were described in 1839 by the Prussian physicist Heinrich Wilhelm Dove, more than eighty years before anyone recorded a human EEG — so the phenomenon long predates any theory about brainwaves.

A binaural beat sends a steady tone to each ear at slightly different pitches — say 200 Hz left, 210 Hz right. Neither channel pulses. Neither contains a 10 Hz anything.

The 10 Hz appears when the two are compared, in the superior olivary complex, the first point in the auditory pathway that receives input from both ears. The beat is constructed in you.

Two consequences follow immediately:

• It requires headphones. On a speaker the two channels sum in the air before reaching your ears, and the difference the effect depends on is gone.
• It has physical limits. The mechanism relies on the auditory system resolving timing differences between the ears, and that ability degrades above roughly a 1 kHz carrier, with the clearest perception in the 400–500 Hz region. The two tones also have to be within a few tens of hertz of one another.

Binaural is by far the most-studied method, and the most romantic — the beat genuinely does not exist until you exist. It is also the weaker driving signal, because nothing in the acoustic waveform is actually modulating.

Monaural: the instructive middle

A monaural beat also uses two tones — but sums them before they reach you. Two tones a few hertz apart interfere, and that interference produces a real rise and fall in amplitude.

So monaural is, in effect, an isochronic tone produced by physics rather than by a volume envelope. It works on speakers. It sounds smoother and less percussive than a switched pulse, because the envelope is a natural beating curve rather than a designed one.

Its own constraint is that the two tones must stay close relative to the carrier. Push them too far apart and they stop fusing into one beating tone and separate into an audible chord — two notes, no pulse.

So which should you use?

Honestly: the differences between these matter less than whether you actually listen.

If you want a defensible default, isochronic on speakers or headphones is the one with the most direct physical claim on your auditory system. If you have good headphones and want the quieter, more diffuse character, binaural is genuinely pleasant and the research base is deepest there — particularly for anxiety, where reductions have replicated across several populations.

The research comparing them directly is thinner than either camp implies. A 2025 parametric study of 80 participants across sixteen binaural conditions found the best attention results from gamma-frequency beats on a low carrier with white-noise masking — and described the effects as modest. That is roughly where the honest summary sits for all three methods.

What Brainwavest does

Most sessions ship as isochronic or phase-amplitude coupled, so they work on whatever you have to hand, and binaural is available as a switch on 754 of 777 — the exceptions target beats above 40 Hz, where the interaural timing mechanism stops working. Monaural is offered on 671.

The Frontier collection is the exception in both directions: it contains sessions designed natively as binaural, monaural and poly-rhythmic rather than as isochronic with alternatives. The 71 binaural and poly-rhythmic sessions genuinely require headphones, and say so before they start.

You can change mode mid-session without restarting it. The carrier, the beat trajectory and the session clock all keep running; only the delivery changes.