Isochronic Tones Generator
Create isochronic tones: a single tone switched on and off at a steady rate, from slow 2 Hz delta pulses to fast 40 Hz gamma pulses. Choose the carrier pitch and pulse shape, mix in soft noise, set a session timer, and listen through speakers or headphones, or save the session as a WAV file.
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For relaxation and focus experiments only; not a medical treatment. Keep the volume low, don't listen while driving, and skip rhythmic audio if you have epilepsy or a seizure disorder. The display never flashes.
How to use the Isochronic Tones Generator
- Pick a preset such as Alpha (10 Hz) or set the pulse rate with the slider or number box.
- Choose a carrier tone: 150 to 300 Hz is comfortable for most people; higher carriers sound brighter.
- Choose a pulse shape: Soft square is clear and click-free, Sine is the gentlest, Hard square the most distinct.
- Optionally blend in noise and set a session length, then press Start tones at a low volume.
- Save a WAV with Download WAV to play the session on your phone or in another player.
How isochronic tones are made
The generator multiplies a steady sine-wave tone (the carrier) by a repeating volume envelope:
output(t) = sin(2π × carrier × t) × envelope(pulse rate × t)
The envelope repeats once per pulse, so one pulse lasts 1000 ÷ pulse rate milliseconds: 500 ms at 2 Hz, 100 ms at 10 Hz and 25 ms at 40 Hz. With a 50% on-time, a 10 Hz soft-square pulse sounds for about 50 ms and is silent for 50 ms. Short raised-cosine edges (a few milliseconds) fade each pulse in and out so you hear distinct beats without clicks.
Isochronic tones, binaural beats and monaural beats
| Isochronic tones | Binaural beats | Monaural beats | |
|---|---|---|---|
| How it is made | One tone switched on and off | A different tone in each ear (e.g. 195 Hz left, 205 Hz right) | Two close tones mixed together in both ears |
| Where the pulse exists | In the sound itself | Only in the brain's processing of both ears | In the sound itself (acoustic beating) |
| Headphones needed? | No | Yes, stereo headphones | No |
| How the pulse sounds | Sharp, clearly separated pulses | Subtle, soft wobble | Smooth swelling and fading |
| Useful range | About 1 to 40 Hz | Perceived best below about 30 Hz | About 1 to 40 Hz |
Want to compare? Try the binaural beats generator with the same rate and carrier.
Preset reference
| Preset | Pulse rate | Carrier | Pulse length | Commonly associated with |
|---|---|---|---|---|
| Delta | 2 Hz | 150 Hz | 500 ms | Deep sleep, winding down |
| Theta | 6 Hz | 180 Hz | 167 ms | Meditation, drowsiness |
| Alpha | 10 Hz | 200 Hz | 100 ms | Calm, relaxed alertness |
| Beta | 18 Hz | 250 Hz | 56 ms | Active thinking, alertness |
| Gamma | 40 Hz | 300 Hz | 25 ms | Concentration |
The band names come from EEG research describing brain rhythms. They are conventions, not prescriptions; how rhythmic sound affects a person varies widely.
Tips
- Quiet is enough. Isochronic pulses are easy to hear even at low volume; louder does not make them stronger.
- Blend in noise at 20 to 40% for long sessions: pink or brown noise softens the pulses and masks distractions.
- Fast rates need higher carriers. At 40 Hz a 300 Hz or higher carrier keeps each 25 ms pulse clearly pitched.
- Pair it with a timer: sessions of 10 to 30 minutes are typical; the fade-out ends the session gently.
Frequently asked questions
What are isochronic tones?
Isochronic tones are a single tone that is turned on and off at regular, evenly spaced intervals (isochronic means equal time). The number of pulses per second is the pulse rate: a 10 Hz isochronic tone switches on and off ten times a second. Unlike binaural beats, the rhythm is physically present in the sound.
Do isochronic tones need headphones?
No. Because the pulsing is in the audio itself, it sounds the same through speakers, a laptop or headphones. Binaural beats, by contrast, only exist when each ear gets a slightly different tone through stereo headphones.
What pulse rate should I choose?
Popular conventions follow EEG bands: delta (1 to 4 Hz) for sleep, theta (4 to 8 Hz) for meditation, alpha (8 to 13 Hz) for relaxed focus, beta (13 to 30 Hz) for alertness and gamma (around 40 Hz) for concentration. Research on whether rhythmic sound reliably changes brain activity or mood is limited and mixed, so treat these as starting points and choose what feels pleasant.
What is the carrier frequency?
The carrier is the pitch of the tone that is being pulsed. It does not set the pulse rate; it only changes how the sound feels. Low carriers (100 to 200 Hz) sound warm, higher ones (300 to 600 Hz) sound brighter and make fast pulses more distinct. Keep the carrier at least about eight times the pulse rate for clean pulses.
Which pulse shape is best?
Soft square is the classic isochronic sound: clearly separated pulses with short smooth edges that avoid clicks. Sine pulses rise and fall gently and are easiest to listen to for long sessions. Hard square is the most pronounced, and Decay sounds like soft drum hits. The on-time slider changes how long the tone sounds within each pulse.
Is it safe to listen to isochronic tones?
For most people, listening at a low, comfortable volume is harmless. Don't listen while driving or doing anything that needs full attention, keep sessions reasonable, and avoid rhythmic pulsing sounds if you have epilepsy or a seizure disorder. This tool is for relaxation and experimentation and is not a medical treatment.
Can I download the isochronic tones?
Yes. Choose a length from 1 to 20 minutes and press Download WAV. The file is created in your browser with the exact settings you hear, including the background noise, and has a short fade-in and fade-out. A 5-minute mono WAV is about 25 MB.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.