The effects are strongest while you are listening to the tones because your brainwaves are synchronized and tuned into the frequency range you desire at that time.  After you've stopped listening the effects can still linger for a while afterwards.  The timescale will vary from person to person and be affected by what you do after you've stopped listening.
If you’re operating in Alpha mode, you’ll feel very present and in the moment. You might be somewhat reactive to the world around you, but you’ll feel like you have time to process what’s going on rather than just react on instinct. This is a wonderful state to achieve when meditating or doing something that requires coordination, focus and learning.
These select frequencies and tones reduce the brain's filtering effect and allows consciousness to be set free. Each recording includes binaural beats, monaural beats, isochronic tones and other sound patterns, combined to deliver a range of delta, theta and alpha rhythms that draw your brain into hypnagogia, the transitional state between wakefulness and sleep.
One RCT (n=108) showed significant reduction in anxiety from a single session of alpha/delta therapy for day surgery patients. A crossover RCT of a single session of theta stimulation in four healthy adults reported significant improvement from the intervention in one of five measures. Five pre/post studies reported significant benefit from the intervention for 16 of 27 outcomes.
Well … to understand the role entrainment plays in meditation, think of a water pump. Most of you have lived in areas where you have access to city water. You turn the knob on the tap, water comes out, end of story. If you grew up like I did, on a farm with a local well, then you probably know that in order to get the water flowing from a well you must first “prime the pump”. (Those of you who remember the days when cars all had carburetors rather than fuel injectors might also remember running out of gas and needing to prime the carburetor with a little gasoline. It’s the same principle.)
I enjoy this one called: Cognition Enhancer For Clearer and Faster Thinking – Isochronic Tones (Electronic) … I seem to enjoy it. Any harm in just listening to this one every day for 30 minutes as a routine daily thing, just like brushing your teeth and making your bed. I would just use it at times when I’m working at my desk, maybe even reading the online news etc…Thoughts?
When blended with musical sounds, brainwave entrainment frequencies induce specific states of mind, which are the result of those brainwaves, delivering them in pleasing and relaxing audio tracts for use with and without stereo headphones. For example, alpha and theta waves, because they exist at the borders between conscious and unconscious thought, are especially rich and useful for tapping into and stimulating subconscious processes.
Entrainment is like priming the pump of meditation. It doesn’t “cause” meditation any more than pouring that little bit of water into the pump initially “causes” water to appear in the well. The water was already there. The conditions for the pump to do its job just needed to be set up. What entrainment does is to create the conditions and the internal environment typically associated with meditation. You could get to that point without entrainment, certainly, but the entrainment allows you to get there quicker, more consistently, and to remain there for longer periods of time than you would ordinarily be capable of doing on your own.

Brainwave entrainment is a colloquialism for such 'neural entrainment', which is a term used to denote the way in which the aggregate frequency of oscillations produced by the synchronous electrical activity in ensembles of cortical neurons can adjust to synchronize with the periodic vibration of an external stimuli, such as a sustained acoustic frequency perceived as pitch, a regularly repeating pattern of intermittent sounds, perceived as rhythm, or of a regularly rhythmically intermittent flashing light.