Research by David Seiver determined that it takes an average of 6 minutes for the brain to become entrained. This is an average. When people get more experienced with brainwave entrainment sessions, entrainment occurs much faster. Most people are in a beta or alpha state when awake and alert. Entraining to alpha should be pretty straightforward. Alpha and beta sessions can be relatively short. The shortest I would go would be 10 minutes.

You must get into an alpha state before accomplishing a theta state. Spend some time in alpha with a rest or a slow ramp. I don't make theta sessions shorter than 20 minutes. 30 or 40 would be better.

The same goes for delta. You must be in a theta state before dipping to delta. Delta sessions should be a minimum of 40 minutes.

As the user becomes more experienced with BWE, entrainment will happen faster. Using post-hypnotic suggestions such as “you will fall into a deep hypnotic sleep faster each time you listen to this session” will hasten the process.

Being the creator of the session, either for yourself or a client, you can quickly edit ramps and frequencies on the fly as the situation warrants!