1. Field of the Invention
The present invention relates to keyboard operated musical instruments. More particularly, the present invention relates to interfacing an acoustic or electrically amplified piano to a digital computer, storage device, or music synthesizer.
2. Description of the Prior Art
Since before the turn of the century, efforts have been made to capture information from acoustic keyboard instruments as the instruments are played. Early devices of this type were predominantly player pianos wherein a performance could be captured in the form of holes on paper that controlled a pneumatic piano control system. The point of such devices was to make one recording on a paper roll of the performance. Thereafter, the performance could be replayed as desired on a player piano by use of a copy of the original paper roll.
One more recent approach to capturing keyboard information during a performance employs a switch matrix including a single matrix row coupled to a bus extending underneath a piano keyboard and having a number of matrix columns corresponding to the number of keys on the instrument. The switch matrix includes a contact on each key operable to contact the matrix bus when the key is operated and thus indicate a switch closure. Such device is shown in U.S. Pat. No. 3,604,299, issued to Englund, Sept. 14, 1971.
The installation of such device is time consuming and, therefore, expensive. Once installed, it is likely that the action of the piano may be affected. Additionally, the open contact and bus system is subject to performance degradation and lack of reliability as the result of oxidation and contact wear. A similar arrangement is provided in U.S. Pat. No. 4,023,456, issued to Groeschel on May 17, 1977.
U.S. Pat. No. 4,104,949, issued to Clark on Aug. 8, 1978, provides a series of keys located on the piano above the keyboard and including sensors responsive to keyboard operation. The location of such device above the keyboard eliminates some of the playing area on the keyboard available to the musician and, thus, interferes with normal keyboard operation.
The most recent approach to capturing keyboard information in a mechanical or electrical manner is shown in U.S. Pat. No. 4,307,648, issued to Stahnke on Dec. 29, 1971 and in U.S. Pat. No. 4,351,221, issued to Starnes et al. on Sept. 28, 1982. Both such devices use an optical switch including a light source and photo cell. Key operation results in movement of a key or hammer within the piano mechanism that produces a corresponding movement of a flag attached thereto. As a result, a beam of light between the light source and photo cell is broken by interposition of the flag, and information is produced corresponding to key operation.
Such devices are installed to the piano action during a time consuming and, therefore, expensive installation procedure. Because there is continual movement of the flag, there is a likelihood that the flag will become dislodged or slip out of alignment and not operate the optical switch properly. Thus, such systems generally require considerable maintenance. Furthermore, the addition of a flag to the piano action might, in some circumstances, affect the action of the piano and, thus, alter or degrade the feel and playing quality of the piano.
An additional problem in prior art keyboard interfaces is that of cabling. A standard piano keyboard has eighty-eight keys. Known keyboard interfaces, therefore, require a cable assembly including eighty-nine wires (eighty-eight key wires and one return or ground wire). Although there have been some attempts to reduce this number of wires through various decoding and latching schemes, generally, significant problems are introduced by the prior art devices when routing cables to transfer electronic signals in response to keyboard operation.
Electronic musical instruments include the well-known electronic music synthesizer, a device that is capable of imitating many known electronic and acoustic instruments, as well as producing its own unique sounds. Electronic music synthesizers are operated by keyboards, or slide controllers or both. One disadvantage of an electronic music synthesizer is that the keyboard generally provided is of a size (that is, number of keys), and has an action or feel unlike that of acoustic pianos. Many musicians have studied on acoustic pianos. A musician who has become accustomed to the feel of a particular keyboard tends to prefer that particular keyboard over other keyboards having a different feel.
Another disadvantage of synthesizers is that they introduce an additional keyboard into a playing configuration. For example, during a performance, a musician who plays both an acoustic keyboard instrument and an electronic music synthesizer has to physically shift between the two. Such additional keyboards take up space in the club or theater where the performance is to be held and provide extra equipment to be transported from location to location in accordance with the musician's itinerary.