Patent No. 4141344 Sound recording system

 

Patent No. 4141344  Sound recording system (Barbara, Feb 27, 1979)

Abstract

In recording an audio program, such as music or voice, on a magnetic tape recorder an A.C. signal generator operating at a frequency below about 14 Hz. provides an A.C. baseline for the audio program signal. This 14 Hz. or lower A.C. signal is sensed by the listener's ear to create an Alpha or Theta state in his brain when the tape is played back.

 

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BACKGROUND OF THE INVENTION

Various methods have been used heretofore to put the human brain into a Theta (below 7 Hz.) or Alpha (7-14 Hz.) brain wave state.

The Alpha state of the brain is considered desirable as promoting relaxation of the body, reducing or eliminating anxiety or mental stress, enhancing the brain's efficiency and creativity, and promoting a feeling of peace and silence.

The Theta state of the brain is associated with peaceful sleep.

In considering the possibility of using conventional magnetic tape recordings to induce the Theta or Alpha state, the first, seemingly insuperable problem is the low frequency limit of conventional tape recording/playback instruments. Those in the low price range (e.g., below $60) typically are not designed for frequencies below 200 Hz. Those in an intermediate price range (e.g., $95-175) typically can handle frequencies down to about 70 Hz. Even tape recorders/players in the price range above $1,000 cannot adequately record or reproduce signal frequencies below 20 Hz.

SUMMARY OF THE INVENTION

The present invention is directed to a novel apparatus and method which enables relatively inexpensive magnetic tape players to be used to stimulate Theta or Alpha brain wave patterns in the listener.

In accordance with the present invention, an audio program is recorded on tape, consisting of signals completely or virtually completely within an audio frequency range substantially above 14 Hz. This audio program may be music, voice, white noise, single frequency tones, or combinations of several different single frequency tones. During the recording of this audio program, which in and of itself would present no difficulty to the recording apparatus, the baseline of the audio program is varied in accordance with a Theta or Alpha signal, which preferably is a single frequency signal, such as 10.53 Hz. Alpha signal. The Theta or Alpha signal provides a very low frequency A.C. baseline for the audio program signal in place of the usual baseline at ground potential. Preferably, the amplitude of the Theta or Alpha baseline signal is about four times the maximum amplitude of the audio program signal, such as music or voice.

It has been found that magnetic tape recordings made this way, when played back, are effective in inducing a beneficial Theta or Alpha state in the listener's brain even though the listener may be only conscious of hearing the music, voice or other audio program from the tape. Also, some listeners with hearing problems are better able to hear the music, voice or other audio program recorded this way.