Speakers and headphones come in two main varieties: Mono and Stereo.

Stereo are by far the more popular. Stereo means you have one channel for the left ear, and a different one playing different sounds to the right ear. Stereo allows you to hear in 3D, just as two eyes allow you to see in 3D.

Mono is a much older option, still offered occasionally. Usually offered in low end speakers or headphones because it is cheaper to manufacture. Mono gives you one channel for both ears. Some people can't tell the difference.

You need stereo speakers and headphones for best results with our subliminals. Part of the build process introduces three dimensional audio, which is designed to force both hemispheres of your brain to work together as a single whole to process the subliminal and thus gives much better results.

If you listen to one of my subliminals in mono, therefore, you will only be getting about half the information. Because it is only half the information, and suddenly your brain is no longer being forced to work as a whole, you won't even get half the impact that you would from using stereo.

if there is ANY other choice, DO NOT USE MONO! If you ever ask me about a speaker and I suggest it, but it is a mono speaker, you know I did not see or know that. I will never suggest a mono appliance if I know it is mono.