Hearing sound, such as music, live has often been considered more pleasurable than hearing the same music after it has been converted into an electronic audio signal and re-converted back into sound (i.e., reproduced sound). There can be many reasons for this perceived drop in quality. One reason resides in the sound reproduction process itself.
Many of the sounds we hear, especially musical notes, are often a composite. For example, a musical note having a basic pitch or fundamental frequency, usually contains other frequency components such as a number of integer multiples of the fundamental frequency called harmonics or overtones. These harmonics create the tonal quality or character (i.e., the timbre) of the note or sound that is often unique to the musical instrument being played, i.e., the sound producing source. In other words, these harmonics enrich the sound we hear. While the human ear typically cannot discern the individual harmonics, it can perceive the presence or absence of these harmonics as an increase or decrease in the quality of the sound, respectively. Equipment for converting live sound into electronic audio signals (e.g., microphones, etc.) typically does not adequately register and convert the full quality of the live sound. That is, the electronic audio signals do not include many of the original harmonics. Numerous sound reproduction systems have been developed in an attempt to add harmonic enhancement to such audio signals. However, these systems are often very sophisticated and expensive and sound produced from such systems may still be perceived to be of a lesser quality than the same sound heard live.
Another reason reproduced sound is often perceived to have a lower quality than live sound can be attributed to the environment in which the sound is produced and recorded. For example, music played in an open field typically sounds one dimensional because much of the sound waves dissipate into the field and are not heard by a listener. On the other hand, music played in an acoustically designed room, i.e., acoustic chamber, usually has a fuller sound and individual sound sources, e.g., musical instruments, are typically more distinguishable, one reason being that the sound heard by the listener includes high quality reverberations.
Not all reproduced sound is originated in an acoustically designed environment and therefore does not contain high quality reverberations. And, even when an acoustically designed environment is used, high quality reverberations which are perceptible by the human ear may get lost in the recording process, for instance if the sound converting equipment (e.g., a microphone, etc.) is unable to register them. In addition, some reproduced sound originates in environments which produce low quality reverberations. Sound reproduction systems have been developed to remove these low quality reverberations. However, in their effort to clean up or remove the unwanted reverberations from the audio signal, desirable or high quality reverberations may be partially or completely removed.
Another problem with reproduced sound, such as music, is that it can become distorted when heard at high volumes. It is often difficult to clearly hear the words being sung in a song or distinguish one musical instrument from another in a piece of music.
An additional problem is that the quality of the reproduced sound can vary depending upon the geometry of the room in which the sound is heard and upon where the listener is located with respect to the source of the reproduced sound (i.e., the speakers). Typically, when this occurs, there will be one or more specific locations of higher quality, often referred to as sweet spots. Thus, in order to enjoy the full potential of such sound reproduction systems, a listener is forced to remain at these sweet spots.
Various systems, a number being very sophisticated and expensive, have been developed in an effort to produce an enhanced electronic audio signal which, when converted into audible sound, is perceived as more closely duplicating the experience of hearing the original live sound. The present invention is an improvement thereon which is relatively inexpensive and simple.